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CXC Study Guide - Biology Unit 2 for CAPE

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Biology
for
CAPE®
Unit
2
Biology
for
CAPE®
Richard
Stuart
Lorna
Fosbery
LaPlace
McPherson
Unit
2
3
Great
Clarendon
Oxford
It
University
furthers
and
the
Oxford
©
Press
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is
a
Richard
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OX2
6DP,
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objective
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Original
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Text
Street,
of
of
UK
Stuart
and
University
Oxford
in
LaPlace
Oxford
the
Kingdom
excellence
worldwide.
the
United
is
certain
and
University
a
of
Oxford.
research,
scholarship,
registered
other
Lorna
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in
trade
mark
of
countries
McPherson
2012
2014
®
CAPE
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a
registered
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First
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Acknowledgements
Cover
photograph:
Mark
Lyndersay,
Lyndersay
Digital,
Trinidad.
Page
make-up
and
2.8.1
Biology
Library;
www.lyndersaydigital.com
illustrations:
Wearset
Ltd,
Boldon,
Tyne
and
diego
4.5.1
The
authors
permission
and
to
the
publisher
reproduce
would
like
to
thank
the
following
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Studio/Fotolia;
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Photo
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cervo/iStock;
Africa
Wear
Media/Science
3.1.2
Lenox
©
4.2.2
Quallo;
Library;
3.2.2
Bruce
Watson;
MBI/Alamy;
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3.1.1
Mary
PHOTOTAKE
3.4.1
4.4.1
©
Evans
Picture
Inc/Alamy;
Lennox
Viviane
3.3.1
Quallo;
4.1.1
Moos/CORBIS;
Juanmonino/iStock.
for
M1
material:
1.3.3
M2
Couchman
5.2.2,
of
CIE
5.2.4
for
The
his
authors
assistance
would
with
like
these
to
thank
Ian
photomicrographs.
Photos
Module
1:
1.1.1
Wood
Unlimited/Science
Photo
2.3.1
Library;
Dr
Don
1.3.3b
Dr.
Oceanographic
Library;
3.4.2
University;
Power
zhan/iStock;
4.2.2
and
©
1.3.3a
Kenneth
Fawcett/Getty;
Loughborough
Quallo;
Hole
Photo
2.7.1
2.7.5
R.
Module
Photo
International
Afripics.com/Alamy;
Clifford;
Photo
4.2.3
Library;
2.8.2
Library;
Krystyna
2.7.3
©
3.4.3
©
Lennox
the
Noel
Hendrickson/Photodisc/Getty;
4.3.2
©
1:
1.3.1
Assessment
Natural
History.
Module
2:
4.3.3
MNS
Photo/Alamy;
4.5.1
Alex
2.3.2,
Tan
Kian
Cambridge
Imagery/Corbis;
iStock
4.6.3
Hibbert/Robert
4.6.1
Steven
Miric/iStock;
4.6.2
of
2:
Laurence
Randy
1.1.1
Kyoungil
Wesson
Moore,
Marian
and
Jeon/iStock;
John
Visuals
2.2.2
Luttick
1.3.1
( James
Unlimited/Science
©
Noel
Allen’s
Photo
Sturt;
Girls’
Library;
1.5.1
Library;
Allen’s
3.4.1,
Girls’
from
©
B
Gunning,
Photo
Springer-Verlag
Library;
3.2.2
3.4.2,
Kallista
3.2.1
Biophoto
5.4.2
School);
Images/Visuals
Laurence
4.2.3
School);
2.1.1
2.1.3
Keith
Dr
2009;
3.1.2
Wesson
and
4.3.2
John
4.4.1
1.5.1,
3:
Global
RubberBall/Alamy;
Fawcett
6.3.2
3:
and
Thomas
1.1.2
Library;
R.
John
4.3.1
Luttick
Carolina
Bavosi/Science
4.4.2
Francisco
Coggeshall/Visuals
Bob
Andy
©
1.3.2
1.2.1
©
PSI/Caribbean;
Crump/TDR/WHO/Science
Health
WHO/P.
Organisation/WHO;
Virot;
©
Photo
2.1.1
2.5.2
2.7.1
Science
Laurence
Picture
Wesson
Photo
University
and
RSA
Examinations
by
(OCR);
and
Physiology
Part
5.5.5
A:
School);
2.7.3
Dr.
P.
by
the
of
World
vampire
blood,
from
Health
Response
bat,
renal
function
Desmodus
Rotundus,
Elsevier.
Organisation
Progress
Report
(WHO);
2011
©
1.5.2
World
Haggerr
1.5.3
from
Island
Matthew
Epidemics
Smallman
by
Andrew
Rayonor.
David
Published
2000.
Press;
Reproduced
with
permission
by
from
©
1999-2005
1.5.4
UCL;
from
3.5.2
www.smallpoxhistory.ucl.ac.uk.
from
Syndicate,
Human
University
Health
and
of
Cambridge
Disease,
1997,
Local
Cambridge
6.1.3
Press;
4.6.1
Reproduced
by
permission
of
University
of
Photo
International
Examinations.
Library.
WHO/John
Library;
we
have
F.
before
made
every
1.6.2
John
publication
effort
this
has
to
not
trace
been
and
contact
possible
in
all
all
copyright
cases.
If
Wickett;
©
the
publisher
will
rectify
any
errors
or
omissions
at
Pan
earliest
opportunity.
Dewald/iStock;
Co/Getty;
Marazzi/Science
and
Stammers/Science
Claudia
and
©
University
2.6.3
Luttick
Photo
to
third
party
websites
are
provided
by
Oxford
in
good
faith
Jenny
for
information
only.
Oxford
disclaims
any
responsibility
for
( James
the
Girls’
of
Reproduced
Photo
Orellano/iStock;
Sinclair
1.5.5
4.6.2
HIV/AIDS
Oxford
and
Matthews/Alamy;
Allen’s
of
of
( James
Links
2.1.2
2.4.2
Biochemistry
permission
Press
the
American
Museum
Biological
Unlimited/Science
Deerinck/NCMIR/Science
Thomas/iStock;
with
University
notied,
1.6.1
American
permission
‘Consumption
water
Oxford
holders
Photo
Cambridge
Photo
Although
Module
by
Cambridge
Busch,
free
Organisation;
Peter
Cambridge
Library;
of
permission
Biophoto
University
Donald
of
Module
Examinations
Dr.
©
by
Associates/Science
Unlimited/Science
Iconotec/Alamy;
Company/PHOTOTAKE;
Library;
3.1.2
Examinations;
Comparative
Cristina
1988,
Copyright
Supply
Reproduced
Oxford,
Copyright
Cliff,
Library;
3.5.1
International
utilization
Health
Associates/Science
Photo
University
Pentek/
from
Wheeler/SPL;
Alliance;
of
reproduced
Anderson/Alamy.
and
Module
Qualication
(p18)
Harding
Physiology,
John
permission
1.9.1
Khoon/
Reprinted
World
by
Szulecka/Alamy;
permission
iStock;
Reproduced
Examinations;
danny
of
4.3.1
permissions
Burgess/Science
Niesen/Shutterstock;
Syred/Science
Chris
Jeremy
Miller/Science
Pete
Text
Institution/Visuals
Dr.
materials
Library;
work.
contained
in
any
third
party
website
referenced
in
this
Contents
Introduction
Module
1.
1
1
v
Bioenergetics
Energy
and
carbon
in
ATP
1.3
Leaf
Biodiversity
50
4.3
Species diversity
52
4.4
Maintaining
biodiversity
1
54
4.5
Maintaining
biodiversity
2
56
4.6
Sampling
ecosystems
1
58
4.7
Sampling
ecosystems
2
60
4.8
Practice
2
living
systems
1.2
4.2
2
4
structure
6
1.4
Introduction to
photosynthesis
1.5
The
light-dependent
1.6
The
light-independent
1.7
Investigating
1.8
Limiting factors
1.9
Practice
stage
stage
8
exam-style questions:
Ecosystems
62
10
12
Module
2
Biosystems
maintenance
Energy
2.
1
2.2
2.3
2.4
photosynthesis
16
exam-style questions:
and
photosynthesis
Introduction to
respiration
Glycolysis
The
The
Introduction to transport
64
1.2
The
66
1.3
Xylem:
1.4
Transpiration
1.5
Measuring transpiration
2.
1
Phloem
74
2.2
Translocation
76
2.3
Assessing the
uptake of
water
and
ions
18
structure
and function
20
70
reaction
and
rates
26
Oxidative
phosphorylation
evidence for
28
Investigating
respiration
Anaerobic
respiration
in
mammals
Anaerobic
respiration
2.9
Respiration:
2.
10
Practice
in yeast
summary
36
and
38
3.
1
Energy
nutrient flow
3.2
Ecological
pyramids
42
3.3
Ecological
efciency
44
3.4
The
4.
1
Ecosystems
nitrogen
cycle
are dynamic
40
46
48
exam-style questions:
uptake
water
in the
34
exam-style questions:
Respiration
Practice
The
32
2.8
78
30
2.4
2.7
72
Krebs
phloem transport
2.6
68
24
cycle
2.5
1.
1
22
mitochondrion
link
64
14
and
and transport of
minerals; transport
phloem
80
3.
1
Blood
82
3.2
Blood vessels
84
3.3
The
86
3.4
Pulse
3.5
Control of the
3.6
The
3.7
Haemoglobin
heart
and
blood
cardiac
of oxygen
pressure
heart
cycle
88
90
92
and the transport
94
iii
Contents
3.8
Haemoglobin
of
3.9
and the transport
carbon dioxide
Practice
The
96
exam-style questions:
mammalian
4.2
4.3
Health
1.6
Summary questions
2.
1
Defence
circulatory
system
4.
1
1.5
Homeostasis
Hormones
in
Regulation of
mammals
infectious
diseases
142
2.2
Non-specic defences
144
2.3
Lymphocytes
146
2.4
The
148
blood
2.5
Antibodies
150
2.6
Types of
152
2.7
Monoclonal
2.8
Practice
102
immune
response
glucose
4.4
Plant
106
4.5
Practice
hormones
immunity
antibodies
Excretion
5.2
The
exam-style questions:
108
Health
5.
1
and disease,
and
110
kidney
nephron
immunology
156
3.
1
Diet
158
3.2
Fats
3.3
Investigating the
112
and disease
excretory functions of the
kidney
114
Osmoregulation
116
in the diet
160
effects of
exercise
5.5
Practice
The
162
exam-style questions:
kidney,
excretion
6.
1
Structure of
6.2
The
6.3
Synapses
6.4
Practice
nerve
3.4
Exercise
and
health
164
3.5
Practice exam-style questions:
and
osmoregulation
neurones
impulse
118
Social and preventative medicine
166
4.
1
Drugs
168
4.2
The
120
122
biological
effects of
124
alcohol
The
Module
nervous
3
170
exam-style questions:
system
4.3
The
social
effects of
4.4
The
effects of
4.5
Chronic
alcohol
172
126
smoking
174
smoking-related
Applications of
diseases
biology
176
128
4.6
1.
1
Health
128
1.2
Dengue fever
130
1.3
HIV/AIDS
1.4
Diabetes
iv
154
exam-style questions:
Homeostasis
5.4
140
100
104
The
against
136
98
concentration
5.3
statistics
and
132
cancer
134
Practice
exam-style questions:
Substance
abuse
178
Glossary
180
Index
186
Introduction
This
Study
Guide
has
been
developed
exclusively
with
the
Caribbean
®
Examinations
candidates,
Council
both
in
)
(CXC
and
out
of
to
be
used
school,
as
an
additional
following
the
resource
Caribbean
by
Advanced
®
Proficiency
Examination
It
prepared
)
(CAPE
programme.
®
has
been
teaching
and
by
a
team
examination.
with
The
expertise
contents
are
in
the
CAPE
designed
to
syllabus,
support
learning
®
by
providing
the
features
and
for
guidance
Inside
this
practice
On
good
Y
our
T
est
in
problem
to
syllabus.
course
is
an
type
Do
and
in
CD
electronic
to
and
Biology
CAPE
master
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refer
key
to
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syllabus
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the
answers
assist
you
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in
techniques:
provide
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sample
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show
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are
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could
skill
level
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answers
be
and
improved.
and
questions.
designed
questions
study
candidate
answers
understanding,
specifically
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examination-style
example
where
examination
examination
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interactive
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for
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ourself
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multiple-choice
refer
This
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you
make
examination
Marks
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These
help
Guide
exam-style
answer
of
of
on
Study
developing

to
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full
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areas.
unique
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invaluable
interactive
support
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help
you
®
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your
have
the
full
potential
included
lots
in
of
Biology.
CAPE
hints,
explanations
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suggestions
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each
of
sections.
®
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textbooks,
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relevant
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Modules
all
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accuracy.
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lessons.
changing.
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examinations.
set
examples
in
in
Y
ou
Caribbean
your
answers.
v
1
Bioenergetics
1.
1
Energy
and
Learning outcomes
carbon
Sources of
Organisms
On
completion
should

list
be
able
the
of
this
section,
of
living
energy
require
a
and
source
systems
carbon
of
energy
and
a
source
of
carbon.
you
to:
sources
in
Organisms
gain
transferred
from
their
energy
reactions
either
from
involving
light
or
elements,
they
use
simple
the
energy
inorganic
energy for
compounds
or
complex
organic
compounds.
organisms
Phototrophs

state
that
living
energy ows
systems
and
is
are
organisms
that
gain
their
energy
by
absorbing
light.
through
not
recycled
Chemotrophs
gain
their
energy
not
from
light
but
from
chemical
reactions.

outline
the
transfer
in
methods
of
energy
The
organisms
simplest
Autotrophs

list
the
types
of
understand
how
to
eat
trees
in
algae
seagrass
in
as
can
convert
use
it
is
into
carbon
dioxide.
complex
the
their
eln
starch,
carbon
forests
amino
as
on
acids
and
organic
carbon-based
Dominica,
proteins.
complex
sugar
cane
compounds
on
the
coral
reefs
waters
around
throughout
St
Kitts,
the
mangrove
in
elds
Caribbean,
trees
in
on
Belize,
their
source
of
phototrophs
use
energy.
terms.
use
simple
obtain
compounds
to
make
compounds.
Most
energy
reactions
in
biological
to
drive
which
the
they
some
seaweeds
use
organic
compounds.
the
to
obtain
to
such
algae,
light
as
but
this
absorb
comes
light
blue-greens,
absorb
energy
These
ocean
floor
are
which
light
reaches.
biological
to
energy
you
directly
from
the
or
Sun.
light
and
energy
some
for
protoctists
such
photosynthesis .
and
xes
carbon
to
make
This
energy-rich
organisms
are
photoautotrophs
vent
communities
These
that
flourish
communities
rely
at
on
depths
bacteria
far
below
that
the
energy
from
simple
chemical
reactions
using
highly
reduced
molecules
and
use
the
energy
released
to
x
carbon.
They
use
need.
compounds
Photosynthesis
is
the
energy
that
is
of
used
compounds
of
and
iron.
This
type
of
nutrition
is
found
of
nitrogen.
These
organisms
are
elsewhere,
chemoautotrophs
to
Heterotrophs
synthesis
sulphur
absorption
utilising
the
food,
turn
make
compounds,
light
other
harnesses
harness
drive
in
complex
compounds
and
they
prokaryotes
and
process
that
that
your
anabolic
On
energy
from
which
molecules.
Heterotrophs
organic
energy
plants,
use
as
light
from
complex
Plants,
organic
your
inorganic
indirectly
of
and
use
Y
ou

organisms
foc us
Autotrophs

that
dioxide
glucose,
food.
they
sunlight

as
obtain
or
these
such
when
Barbados,
should
carbon
carbon
Heterotrophs
Whether
You
of
nutrition.
compounds,
S tudy
form
absorb
feed
in
a
variety
of
different
ways,
for
example
by
grazing
simple
plants,
preying
on
animals,
parasitising
other
organisms
and
eating
dead
carbohydrates.
and

Respiration
is
the
transfer
decaying
compounds
complex
to ATP
organic
and
heat.
digest
digest
their
absorbing
Energy
to
Did you know?
be
A
TP
,
organisms
however,
rely
respire. Viruses,
host
on
Viruses
as
they
cells
the
are
do
the
not
to
be
respiration
out
any
in
parasitism
in
table
way
of
Energy
Much
respiration
(or
or
lter
to
get
their
food;
a
gut
secreting
or
inside
cells;
enzymes
onto
bacteria
their
and
food
fungi
and
products.
inside
available
is
inside
by
the
which
for
organisms,
work.
universal
energy
in
All
which
energy,
energy
in
can
cur rency
carbon-based
be
stored
whatever
inside
cells
compounds
or
form,
is
transferred
is
(see
released
page
released
4).
as
The
is
on
page
3
summarises
the
different
forms
of
nutrition.
transfer
energy
make
is
in
photosynthesis
transferred
use
of
this
by
heat
and
heating
–
it
just
respiration
the
is
not
organism.
leaves
and
very
Most
heats
efcient.
organisms
their
surroundings.
anything
and
mammals
are
endotherms
in
that
they
can
themselves.
use
2
suck
of
Birds
else) for
chew,
reproduced.
ultimate
have
internally
externally
available
which
cannot
carrying
bite,
respiration
The
their
is
food
food
the
made
process
All
They
of
most
energy from
organisms.
it
to
help
maintain
a
constant
body
temperature.
retain
the
heat
and
Module
Source of
energy
Source of
carbon
S tudy
carbon
dioxide
complex
1
foc us
Photosynthesis and respiration are
carbon
(autotrophic)
compounds
(heterotrophic)
light
photoautotrophic
photoheterotrophic
(phototrophic)
photosynthetic
purple
not opposites of one another. Look for
reasons for this as you read this
bacteria,
chemical
reactions
bacteria
Summary question 4 on page 37 in
Section 2.9.
some
protoctists
algae,
non-sulphur
chapter and the next. Then answer
including
plants
chemoautotrophic
chemoheterotrophic
nitrifying
many
(chemotrophic)
(see
bacteria
page
47)
bacteria,
protoctists,
many
all fungi
and
all
animals
Eventually,
this
the
is
the
however
,
fate
of
atmosphere
all
this
energy
energy
and
is
that
radiated
also
leaves
enters
into
and
living
space
as
heats
the
systems.
infrared
It
surroundings
is
transferred
and
to
radiation.
Figure 1.1.1
These deep-sea giant
Sun
tubeworms, Riftia
pachyptila, live in vent
communities. Chemoautotrophic bacteria
plants
and
provide the energy for these communities.
other
photoautotrophs
herbivores
decomposers
Did you know?
chemoheterotrophs
The
deepest
found
in
vent
2010
in
communities
were
the Cayman Trench
carnivores
between Jamaica
heat
transferred
e
Figure 1.1.2
and
to
and Cuba.
the
then
Energy flows, it is not recycled
Link
Energy
is
used
in
organisms
for:
Energy

active
is
the
ability
to
do
work
and
is
transport
measured

movement

biosynthesis
First
–
the
production
of
biological
Law
raising

growth
energy

maintenance
levels
of
compounds
so
they
take
part
in
is
body
transfer.
temperature
in
the
neither
created
–
nor
reactions
reproduction
of
Remember
of Thermodynamics
destroyed.
and
joules.
molecules
energy

in
endotherms.
transfers
Life
Note
is
all
all
about
the
mentioned
Summary question
energy
energy
here
and
answer
3.
Summary q uestions
1
Explain
2
Dene
why
the
energy ows
terms:
and
is
not
recycled.
autotroph, photoautotroph, chemoautotroph,
heterotroph, carbon fixation,
S tudy
foc us
photosynthesis, respiration
Energy ows,
3
Draw
an
energy ow
diagram for
a farm
where
crops
are
grown
to feed
it
does
not
cycle.
to
Never
write
about
‘energy
cycling’
or
livestock.
‘energy
4
Explain
what
will
happen
to
life
on
Earth
when
the
Sun
dies.
is
examples
recycled’.
of
See
page
40 for
energy ow.
3
1.2
ATP
A
TP
Learning outcomes
as
On
completion
should
be
able
of
this
section,
it
is
one
is
the
shows
you
state
that ATP
energy
is
the
currency
most
The
base
With
a
important
used
molecular
nucleotide.
to:
the
molecule
the
adenosine.

of
by
all
structure
adenine
phosphate
molecules
organisms
of
A
TP
,
and
for
which
sugar
added
you
learn
energy
is
ribose
this
will
a
about
transfers.
in
Biology
Figure
1.2.1
phosphorylated
together
becomes
a
form
the
nucleoside
nucleotide.
universal
within
cells
in
NH
all
2
organisms
C
N
adenine

describe
the
structure
of ATP
as
N
a
C
CH
phosphorylated
nucleotide
HC
C
N
N

explain
how ATP

outline
how
reactions
is
produced
oxidation/reduction
are
involved
OCH
O
2
in ATP
H
H
production

list
the
roles
of ATP
in
cells.
HO
OH
ribose
S tudy
foc us
adenosine
You
should
be
able
to
make
a
adenosine
diagram
of ATP
using
shapes
monophosphate
simple
diphosphate
to
Figure 1.2.1
represent
each
the
adenine,
phosphate
group.
ribose
See
and
adenosine
Summary
A
TP
question
Molecular
structure of ATP
triphosphate
is
the
energy
transfer
molecule
within
cells.
It
is
highly
suited
to
this
1.
role
of
as
it
is
small
production
are
unstable
to
and
sites
and
soluble
of
break
use.
so
diffuses
The
easily.
bonds
Many
through
between
proteins
a
cell
the
within
easily
from
phosphate
cells
sites
groups
recognise
the
Link
adenine
and
unstable,
Remember
what
you
learnt
in Unit
active
sites. ATP ts
into
of
sites
Module
also
that
those
such
many
in Unit
anabolic
that
as
of
1
make
enzymes.
1.
larger
protein from
See
There
shown
are
molecules,
amino
glucose
or
acids,
nucleic
very
for
is
easily.
an
very
in
releases
the
molecule,
energy
which
so
acts
like
transfers
a
one
‘handle’.
or
two
As
it
is
phosphate
hydrolysis
step
of
of
an
most
A
TP
molecule
anabolic
supplies
enough
reactions.
in
a
or
a
single
in
a
The
‘packets’
glucose
A
TP
A
TP
1.2.2.
of
cell.
great
energy
The
rather
triglyceride
reaction;
to
A
TP
is
advantage
than
molecule.
transfer
constantly
is
that
recycled
when
the
energy
released
Also
energy
is
energy
from
as
hydrolysed
it
by
transferred
glucose
in
acids
‘packets’
and
not
a
mini
explosion
requires
many
reactions
nucleotides.
as
you
energy
cells.
ATP
The
little
small
manageable
from
of
activation
individual
Figure
oxidising
from
starch from
part
low
3.
1
Remember
reactions
a
the
energy
active
sugar
has
1
groups
about
it
will
is
see
on
pages
converted
Even
when
into
they
20
to
A
TP
29.
and
produce
Although
not
their
used
own
phototrophs
directly
light
to
absorb
drive
light,
processes
the
in
(bioluminescence)
synthesis
hydrolysis of
using
organisms
use
A
TP
as
the
source
of
energy.
energy
ATP
to
from:
There
ADP  P
are
two
ways
in
which
A
TP
is
produced:
provide
•
oxidation
of
energy for

carbohydrates,
substrate-linked
phosphorylation ,
in
which
A
TP
is
produced
by
direct
biosynthesis,
proteins
and
synthesis
in
a
reaction
in
which
energy
in
chemical
bonds
is
reorganised
movement,
fats
in
active
respiration,
or

ATP
chemiosmotic
phosphorylation,
in
which
a
proton
gradient
is
transport,
•
light
responsible
in
for
synthesis
of
A
TP
–
this
occurs
in
mitochondria
and
etc.
photosynthesis
Figure 1.2.2
chloroplasts
in
eukaryotic
cells.
ATP is hydrolysed when it
A
TP
is
produced
in
some
reactions
that
occur
on
the
surface
of
an
enzyme.
of
an
enzyme.
forms ADP and phosphate. When
ADP
and
a
phosphorylated
compound
occupy
the
active
site
reformed, a condensation reaction occurs
between ADP and a phosphate. Enzymes
catalyse the formation of ATP.
4
A
phosphate
glycolysis
group
(see
page
transfers
22)
and
from
the
the
Krebs
compound
cycle
(see
to
ADP
.
page
26).
This
happens
in
Module
Most
A
TP
is
established
using
a
form
gradient
the
by
of
gradient
of
maintain
through
In
to
gradient.
from
The
the
the
one
membrane
enzyme
form
in
A
TP
.
The
This
of
a
can
only
A
TP
energy
for
is
the
another
down
accept
from
that
As
ADP
by
such
cuttlesh
to
for
as
squids,
deep
lures
signalling
and
is
as
and
functions:
the
pumping
Animals
as
by
oxidation/reduction
reactions
that
occur
between
a
to
during
camouage.
use
variety
attract
of
prey;
courtship
Search for
made
bioluminescence
available
sea sh
bioluminescence for
the
energy
provided
proton
Did you know?
to
synthetase.
to
comes
provides
energy
is
return
shape
energy
light
the
gradient
membrane
protein
changes
The
respiration,
compounds.
side
protons
photosynthesis,
gradient;
organic
proton
transport.
through,
protons.
of
a
protons
phosphate
this
oxidation
active
diffuse
inorganic
using
pumping
diffusing
protons
and
produced
by
1
and
see
some
compounds
examples.
in
the
membranes
page
180
to
nd
A
TP
functions
of
mitochondria
denitions
by
binding
of
and
chloroplasts.
oxidation
and
Use
the
glossary
on
reduction.
to:
Did you know?

proteins
and
for
movement,
e.g.
muscle
contraction,
movement
of
cilia
The
flagella
is

carrier

inactive
proteins
for
active
total
about
to
activate
enzymes,
so
reactions
can
to
take
lot
constitute
is
turned
as
transfers:

phosphate
a
glucose
to
glycerate
group
form
to
a
molecule
glucose
phosphate
so
increasing
6-phosphate
(GP)
in
the
in
Calvin
its
glycolysis
cycle
reactivity,
(see
(see
page
page
e.g.
22)
8000
enough

AMP
energy
to
a
to
provide
molecule
by
to
activation
increase
attaching
to
note
about
its
energy
for
reactivity,
most
e.g.
to
reactions
amino
in
A
TP
is
not
per
is
acids
when
that ATP
as ATP
synthetase
A
TP
is
they
need
cells,
not
stores
The
of
polysaccharides
energy;
enough
A
TP
transported
it.
have
This
many
is
also
synthase. There
synthetase
glycogen
and
starch
lipids
are
long-term
stores
of
is
enzymes;
glycogen
are
another
in
a
cell
to
act
as
a
is
between
why
very
cells.
active
It
is
cells,
synthetase
(see
are
105).
Substrate-linked
energy.
is
also
known
as
store.
substrate-level

estimated
A
TP:
stored.
not
is
hour.
foc us
phosphorylation
There
the
tRNA.
page
short-term
as
a few
cells
example

in
to
many
to
store
12)
known
Points
human
to
and
Note
activated
a
over
turnover
grams
S tudy

a
not
place.
seconds. The
A
TP
in
is
them
whole

of ATP
grams. There
transport
enough
enzymes
quantity
50
produced
such
as
by
liver
cells
and
phosphorylation.
when
muscle
mitochondria.
Link

A
TP
nd
does
in
not
older
have
‘high-energy
textbooks
and
in
bonds’.
some
This
websites.
is
a
concept
The
energy
that
you
will
released
Chemiosmotic
when
A
TP
is
hydrolysed
comes
from
the
whole
molecule,
not
occurs
bonds
between
the
phosphate
A
TP
is
not
a
high-energy
compound.
For
its
molecular
mass
it
has
energy
level.
It
chloroplasts
is
small
and
soluble,
which
makes
it
processes
energy
membranes,
and
are
in
mitochondria.
essentially
the
good
same
for
bacterial
an
The
intermediate
across
groups.
in

phosphorylation
the
(see
page
29).
transfer
.
Summary q uestions
S tudy
1
Make
a
simple
diagram
of ATP.
Label
the
parts
and
annotate
with
functions.
There
cells,
2
Make
simple
drawings
of
a
bacterium,
a
mitochondrion
and
a
is
on
each
diagram
a
the
direction
in
which
hydrogen
always
but
the
ions
3
Dene
and
the
b
where ATP
terms:
chemiosmosis,
is
oxidation,
is
inside
too
small
to
an
activity
without
being
are
recycled. You
pumped,
some ATP
quantity
chloroplast.
power
Indicate
foc us
their
could
probably
swing
a
produced.
reduction,
phosphorylation,
substrate-linked phosphorylation
‘energy currency’,
golf
club
you
certainly
more
on
the ATP
could
in
your
not
do
muscles;
anything
strenuous.
5
1.3
Leaf
structure
Leaves
Learning outcomes
On
completion
should

be
able
recognise
tissues
of
and
describe
cell
identify
types
section
dicotyledonous

section,
the

absorbing

obtaining

producing

export

import

support,

explain
and
of
in
a
structures
cell
how
out
of
different
tissues.
They
are
adapted
for:
light
carbon
dioxide
by
diffusion
from
the
atmosphere
and
in
leaves,
a
in
photosynthesis
of
sugars
and
amino
acids
a
leaf
of
a
in
of
water
so
and
they
ions
present
a
large
surface
area
to
the
source
of
light.
a
functions
of
the
tissues
shown
in
the
gures
are
described
in
the
table.
chloroplast
palisade
are
sugars
the
plant
chloroplasts
carry
composed
you
The
palisade
organs
to:
and
transverse
this
are
cells
adapted
Tissue
Function
upper
secretes
to
photosynthesis.
epidermis
cuticle
light
upper
cuticle
waxy
and
to
that
epidermal
pass
stomata
cuticle
through
(see
lower
reduces
cells
to
are
the
loss
of
transparent
mesophyll;
epidermis
water
to
may
vapour;
allow
have
below)
epidermis
chloroplast
air
space
palisade
palisade
cells
mesophyll
light;
contain
many
chloroplasts
to
absorb
maximum
mesophyll
large
vacuole
pushes
chloroplasts
to
the
edge
of
spongy
mesophyll
each
cell;
cells
are
cylindrical
and
at
right
angles
to
vascular
bundle
epidermis
to
spongy
cells
mesophyll
mesophyll
reduce
separated
by
scattering
larger
air
of
light
spaces
by
than
cell
in
walls*
palisade
lower
epidermis
sub-stomatal
air
space
guard
allow
the
diffusion
leaf**;
air
of
carbon
spaces
also
dioxide
act
as
a
store
of
cell
carbon
Figure 1.3.1
to
throughout
stoma
dioxide
when
stomata
are
closed
A drawing made from a
cross-section of the blade of a
xylem
xylem vessels
supply water
and
ions
(see
pages
68–71);
dicotyledonous leaf showing all the tissues
water
passes from
xylem
along
cell walls of
mesophyll
listed in the table
cells
phloem
lower
epidermis
and
is then
phloem
sieve
sucrose
and
parts
the
cells
of
are
aperture
oxygen
Figure 1.3.2
of
tubes
amino
by
individual
transport
acids,
cells
assimilates,
away from
the
by osmosis
such
leaf
as
to
other
plant
like
specialised
absorbed
those
as
of
pairs
stomata
diffuse
in
the
of
upper
guard
through
and
out
epidermis;
cells
that
which
some
control
carbon
and
water
have
more
are
the
dioxide
vapour
and
diffuses
out.
A cross-section of the
The
leaves
of
most
dicotyledonous
plants
stomata
on
the
central vein of a leaf of Ligustrum (×10).
You can see the blade of the leaf on each
side.
lower
surface
epidermis.
stomata
Light
the
upper
.
that
Many
float
have
on
none
water
at
have
all
on
almost
the
all
upper
their
surface.
foc us
would
be
scattered
rather
**
through
Diffusion
the
leaves
upper
horizontally
cytoplasm,
6
on
However
,
on
S tudy
*
than
which
than
is
air
the
by
cell
walls
if
the
cells
were
arranged
in
layers
vertically.
is
much faster
advantage
of
than
diffusion
having
all
the
through
large
air
cell
walls
spaces.
and
Module
Palisade
many
cell
mesophyll
chloroplasts.
so
that
describes
they
the
cells
On
are
are
hot,
not
structures
all
in
adapted
bright
for
days,
exposed
to
photosynthesis
chloroplasts
the
chloroplasts
most
and
intense
their
as
they
move
contain
around
light.
The
in
Link
table
functions.
See
2.3
check
in
Module
you
have
palisade
Summary
A
stoma
is
between
often
and
Electron
Figure 1.3.3b
cell
of Unit
1
to
the
organelles
when
answering
in
1.
foc us
really
the
used
the
1
all
question
S tudy
micrograph of a chloroplast. In the
Bioenergetics
the
the
Figure 1.3.3a
1
just
guard
to
the
hole
cells,
mean
the
but
it
guard
is
cells
hole.
Grana surrounded by stroma and, at
the top, a chloroplast envelope (×80 000)
Link
centre is a starch grain (×10 000)
Dicotyledonous
of owering
Structure
Composition
also
outer
and
inner
membrane
protein
carriers
each
composed
of
export
of
bilayer
and
proteins
and
triose
entry
of
phosphate,
and
with
have
group
two
broad
cotyledons.
leaves
with
a
Many
net-
pattern
of
veins.
See Unit
1
phosphate
Module
phospholipid
the
have
allow
like
–
to
that
Function
embryos
envelope
refers
plants
ions,
3.
e.g.
magnesium
nitrate
Summary q uestions
stroma
colourless,
protein-rich
enzymes
catalyse
1
region
surrounding
the
reactions
to x
Make
to
grana;
contains
DNA
dioxide
and
a
drawing
show
many
ribosomes
enzyme
and
biological
molecules
as
lipids,
amino
molecules
stack
(plural
called
grana)
of
membranous
sacs
thylakoids
hexoses,
acids
provides
area for
and
a
and
large
light
electron
pumps
contain
protein
carriers,
and ATP
move
proton
synthetase
sac
in
cell
an
surface
2
Label
annotate
how
cell
is
the
it
adapted
photosynthesis
Make
diagram
to
your
show
to
carry
Label
to
the
the
to
shown
how
structures
and form ATP
carry
based
on
structures
annotate
show
efciently.
micrographs
chloroplast
of
stage
inside
a
electron
into
space
micrograph.
and
proteins
complexes
protons
thylakoid
palisade
drawing
table;
membranes
a
visible
starch,
absorption
light-dependent
thylakoid
detail
such
out
granum
the
produce
electron
loops,
of
carbon
this
page.
in
the
diagram
different
enable
out
the
the
given
your
the
on
of
the
chloroplast
photosynthesis
efciently.
DNA
loops
DNA
of
double-stranded
(similar
to
those
of
prokaryotes)
DNA
the
codes for
proteins
chloroplast;
transcribed
of
used
in
genes
as
chloroplast
coded for
some
by
of
the
3
require
are
mRNA;
and
rest
proteins
nuclear
Suggest
why
enter
smaller
than
Calculate
ribosomes
on
translation
–
assembly
and
within
same
size
reticulum
the
as
prokaryotes
cytosol;
those
in
amino
acids
proteins
b
how
these
the
in
actual
length
Figure
1.3.3a.
of
the
Show
of
your
endoplasmic
magnesium
and
chloroplasts.
chloroplast
ribosomes
ions,
DNA
4
70S
chloroplasts
phosphate,
nitrate
ions
are
a
working.
to form
5
Explain
why
species
do
the
upper
leaves
not
of
have
many
stomata
on
surface.
7
1.4
Introduction
The
Learning outcomes
to
photosynthesis
process
of
photosynthesis
may
be
light
On
completion
of
this
section,
you
nCO
+
nH
2
O
summarised
by
this
equation:
energy
→
(CH
2
O)n
+
nO
2
2
chlorophyll
should
be
able
to:
enzymes

state
that
photosynthesis
This
involves
the
transfer
of
1,
energy
to
simple
sugars
chemical
equation
energy
you
studied
of
state
the
energy
raw
and
materials,
products
source
of
of
many
the
two
reaction
stages
stage
and
state
the
what
such
happens
as
the
in
photosynthesis.
hydrolysis
of
starch
In
to
Unit
form
In
but
you
is
the
then
Unit
Y
ou
do
is
not
is
you
do
need
not
to
study
have
know
detailed
substrate
this
2
rate
of
the
metabolic
to
an
learn
limiting
If
and
the
overview
enough.
next.
all
pathways,
In
a
one
slows
of
reactions
these
pathway,
reaction
down
which
is
the
of
consist
the
reactions.
the
The
product
slower
of
than
remaining
one
the
slow
production
of
the
nal
product.
Y
ou
will
see
how
reactions
this
applies
to
light-dependent
photosynthesis
on
pages
Photosynthesis
occurs
16
and
17.
light-independent
stage

of
reactions
of
with
photosynthesis:
summary
reactions.
equation
others,
outline
sugars.
pathway,
simple
photosynthesis

a
single
in
reducing

is
light
precise
sites
of
the
in
two
stages:
two

light-dependent
stage
light-independent

stage
stages.
The
they
S tudy
diagram
are
shows
where
they
are
located
in
the
chloroplast
and
how
related.
light
foc us
chloroplast
envelope
There
is
no
need
learn
equation,
or
It
important
is
more
the
to
one
this
in
which
to
know
n = 6.
thylakoids
that
H
carbon
raw
the
dioxide
materials,
product
and
water
simple
and
are
sugars
oxygen
is
light-dependent
O
reactions
O
2
the
2
are
the
phosphate
ions
by-product.
chloroplast
reduced
ATP

envelope
NADP
stroma
CO
light-independent
2
triose
reactions
phosphate
chloroplast
envelope
Figure 1.4.1
The exchanges that occur between chloroplasts and the rest of the cell, and
the sites of the two stages of photosynthesis and exchanges between them
Plants
Link
are
phototrophic
(phototrophic)
Note
that
all
the
photosynthesis
Mitochondria
stages
occur
are
the
in
autotrophs.
in
the
The
absorption
light-dependent
stage.
of
light
This
stage:
of

occurs

involves
in
the
grana
chloroplasts.
the
transfer
of
light
energy
to
chemical
energy
in
the
form
of
equivalent
two
organelle for
occurs
coenzymes,
A
TP
and
reduced
NADP
respiration. The rst
+
stage
not
of
respiration,
occur
outside
in
inside
the
glycolysis,
mitochondria,
cytosol
(see
does

22).
the
electrons
but
page
involves

involves
(e
the
splitting
of
water
(photolysis)
to
give
protons
(H
)
and
)
production
of
oxygen
(O
)
2

involves
electron

involves
that
8
the
harnessing
of
energy
as
electrons
flow
along
chains
of
car riers
electrons
consists
of
flowing
along
substances
that
the
are
electron
transport
alternately
reduced
chain
and
(ETC)
oxidised.
Module
The
xing
of
carbon
dioxide
(autotrophic)
occurs
in
the

This
occurs

foc us
stage:
in
the
stroma
involves
the
acceptor
compound
Do
combination
of
carbon
dioxide
with
a
ve
carbon
not
and
(5C)
of
use
the
involves
the
use
of
A
TP
and
reduced
NADP
to
drive
the
production

three
involves
This
the
T
riose
of
its
of
sugar
,
of
pathway
products
one
(3C)
resynthesis
metabolic
from
after
carbon
the
is
does
not
ve
cyclic
carbon
discoverers,
phosphate
triose
the
fixation .
Melvin
acceptor
photosynthesis. The
a
number
of
other
the
acceptor
It
is
Calvin
accumulate
in
substance
known
as
the
is
Some
and

is
used
fructose
Glucose
which
to
light-
does
not
happen
Link
cycle
(1911–1997).
the
chloroplast;
it
is
No-one
is
protons
are
quite
sure
how
pumped,
the
although
there
converted
plenty
of
evidence
that
it
happens.
substances:
make
hexose
phosphates,
such
as
glucose
phosphate
will nd
page
this
evidence
on
29.
phosphate.
phosphate
are
stages
dark.
recycled
Calvin
You

stage
two
substance.
is
into
light reaction
the
phosphate
carbon
as
for
of
in
the
terms
dark reaction
independent

Bioenergetics
light-independent
S tudy
stage.
1
stored
is
in
used
the
to
synthesise
starch
grains
in
amylose
the
and
amylopectin,
chloroplast.
Summary q uestions

Much
is
exported
proteins
in
the
from
the
envelope
chloroplast
for
use
in
the
through
cytosol;
triose
this
transporter
is
converted
into
1
hexose
phosphates
transport

Some
is
in
the
and
used
to
make
the
disaccharide
sucrose
Name
the
two
stages
of
for
photosynthesis
and
precisely
they
state
phloem.
converted
into
other
biochemicals,
e.g.
fatty
acids,
where
occur
in
a
amino
plant
cell.
State
the
acids.
2
Oxidation–reduction
reactions
occur
during
both
stages.
When
raw
materials for
two
photosynthesis
substances
react
in
this
way,
electrons
are
donated
from
one
substance
pathway
the
other
.
Oxidation
Some
is
the
loss
substances
of
react
electrons
more
and
readily
reduction
than
is
others
the
and
gain
have
levels.
complexes
that
potentials).
While
have
with
when
this
electron
pass
low
they
with
from
energy
gain
happens
transport
molecules
Electrons
compounds
reduced
The
the
energy
is
as
electron
composed
different
compounds
levels;
is
chain
they
and
transferred
energy
with
do
so
of
to
pump
(redox
energy
those
3
levels
compounds
when
they
protons
to
the
place
where
are
used.
protein
levels
high
oxidised
of
the
the
high
they
energy
outline
they follow from
environment
electrons.
and
to
lose
across
to
State
the
products
dependent
are
the
it.
roles
stage
they
independent
of
and
play
in
the
light-
outline
the
light-
stage.
the
4
a
Name
the
by-product
of
the
membrane.
light-dependent
Much
of
the
experimental
work
on
photosynthesis
is
done
algae,
such
as
Chlorella
and
Scenedesmus .
These
cells
in
Chloroplasts
lettuce,
suitable
can
spinach
blender
,
or
ltering
suspension
of
also
solutions
be
isolated
callaloo.
the
and
This
from
is
homogenate
chloroplasts.
exposed
done
and
Often
the
it
a
different
leaves
by
of
the
good
up
ltrate,
idea
to
such
the
leaves
which
spin
the
5
as
will
in
grains
and
or
leave
small
it
to
debris
stand
from
in
ice
the
or
cells
in
are
a
refrigerator
so
ltrate
that
what
a
in
Name
suspension
when
it
is
of
chloroplasts
reduced.
If
in
light
this
is
is
mixed
put
white
of
left
high
in
the
as
the
molecules
of
the
blue
a
dark,
dye
term
by-product
the
product
stage
happens
Suggest
why
reaction
and
blue
the
dye
that
mixture
is
decolourised
the
blue
colour
stays
be
to
chloroplasts.
on
page
18
and
19
the
and
light-
outline
the
terms
light
are
the
refer
two
should
stages
of
blue.
A
chloroplast
with
suspension
the
blue
redox
dye
reduced.
in
questions
of
it.
the
blue. When
light,
the
to
suspensions
of
algae
and
suspension
is
be
placed
blue
disappears. What
the
used.
disappears
Link
of
is
dark reaction
used for
appears
Some
state
explain
photosynthesis.
mixed
quickly
b
removed.
with
intensity
and
a
7
When
it,
starch
not
A
the
independent
a
be
6
centrifuge
to
conditions.
plants
breaking
using
is
to
happens
are
why
suspended
and
with
what
unicellular
stage
colour
colour
after
the
will
the
blue
dye
decolourised?
9
1.5
The
light-dependent
Chloroplasts
Learning outcomes
absorb
On
completion
should
be
able
of
this
section,
you
light.
spectrum
absorb
to:
name
the
chloroplast
Plants
between
most
regions

of
describe
their
pigments,
absorb
the
strongly
the
which
light
in
the
wavelengths
at
either
spectrum.
If
end
white
are
of
of
coloured
visual
400
this
light
is
part
and
compounds
of
the
700 nm.
range
shone
–
in
electromagnetic
The
the
onto
a
that
pigments
blue
and
red
suspension
of
pigments
chloroplasts
and
contain
stage
role
made
from
a
leaf,
it
is
the
light
in
those
regions
that
is
in
absorbed
and
green
light
which
passes
through.
This
is
why
leaves
appear
photosynthesis
green,

explain
and
how
used
reduced
to
energy
is
trapped
produce ATP
reflected
and
on
a
explain
how
provide
or
graph
the
wavelengths
transmitted,
is
an
not
absorption
in
the
green
absorbed.
The
region
of
pattern
the
of
spectrum
absorption
spectr um
a
photolysis
source
of
occurs
electrons
table
shows
the
chloroplast
pigments
to
Pigment
and
Colour
protons.
chlorophyll
a
yellow-green
Peak
Function
absorption/nm
photosynthesis
430,
absorbs
662
in
red
blue-violet
S tudy
up
the
b
blue-green
453,
642
absorbs
red
visual
to
light
see
and
the
the
wavelengths
other forms
with
higher
and
light
of
of
β
energy
and
electromagnetic
blue-violet
spectrum
and
light
foc us
chlorophyll
Look
are
shown
NADP
The

because
carotene
orange
450
yellow
450
absorbs
blue-violet
light;
lower
may
protect
chlorophylls
wavelengths.
xanthophylls
to
470
from
and
damage from
light
oxygen
Link
If
Absorption
spectra
and
light
or
spectra
are
shown
on
of
different
page
unicellular
least
Link
Figure
diagram
of
on
proton
page
29 for
movement
The
a
across
The
effective
action
2.5.2
algae
membrane
like
that
of
pigments

in
in
foc us
the
centre
has
maximum
known
the
ways
reduced form
of
to
the
write
down
the
as
There
of
a
It
is
perfectly
reduced
NADP,
suspension
of
chloroplasts
occurs
are
at
the
The
blue
and
pattern
red
can
shown
regions
be
on
a
and
graph
the
is
an
are
a
two
are
arranged
reaction
of
these
into
centre .
light-harvesting
Each
one
is
a
photosystems:
I
(PSI)
each
photosystem
maximum
and
P
at
.
photosystem

is
a
absorption
680 nm.
Energy
is
chlorophyll
at
The
700 nm
from
(PSII).
molecule.
and
chlorophyll
transferred
a
II
in
PSII
it
molecules
accessory
In
PSI
has
are
this
a
often
pigments
to
680
centre.
but
if
you
of
you
may
many
wavelengths
is
absorbed
and
the
energy
excites
an
electron
to
the
centre
of
the
chlorophyll
and
accepted
molecule
in
PSII.
This
excited
electron
are
leaves
studying Chemistry
a
photosynthesis
co-enzyme
acceptable
in
write
at
which
region.
chloroplast
absorption
P
reaction
Light
NADP.
green
around
700
various
shone
at
wavelengths
the
the
arranged
photosystem
molecule
are
is
rate
spectr um
complexes
At
There
the
the
thylakoid.
S tudy
best
are
photosystem .
a
then
18.
determined.
See
wavelengths
action
wish
is
by
one
of
the
electron
carriers
in
the
thylakoid
to
membrane.
As
it
passes
from
carrier
to
carrier
,
energy
is
released
in
small
+
write
NADPH
+
H
‘packets’
stroma
and
into
is
the
used
by
the
thylakoid
carrier
space.
molecules
This
is
a
to
form
move
of
protons
active
from
the
transport.
Did you know?
The
One
of
the
polypeptides
in ATP
electron
absorption
accepted
synthetase
rotates.
It
is
the
engine found
so far!
NADP
.
10
by
now
has
light
by
another
a
lower
this
energy
level
photosystem
electron
carrier
.
when
it
reaches
re-energises
From
here
it
the
PSI.
The
electron
travels
to
and
NADP
,
it
the
electron
and
a
proton
from
the
stroma
to
become
is
which
smallest
accepts
rotatory
of
reduced
Module
The
reduction
outer
surface
electrons


then
protons
a
by
NADP
membrane.
reductase,
There
are
two
which
is
pathways
on
the
for
to
keep
take
return
leaving
their
non-cyclic
enzyme
they
–
electrons
to
travel
from
PSI
but
Link
that
You
can nd
PSII
place.
–
electrons
so
more
W
ater
is
have
the
travel
the
on
the
inner
to
source
photophosphorylation.
enzyme
catalyses
ATP
synthetase
side
from
come
of
This
of
PSII
to
S tudy
because
thylakoid
there
membrane.
O
→
The
the
dependent
4H
4e
electrons
to
+
is
the
light
that
light-
intensity.
reactions
are
not
O
2
PSII
and
protons
to
the
pool
of
protons
in
much
by
temperature
and
the
this
accumulate
space
which
electrochemical
membrane
pass
stage
of
dioxide
is
not
involved
with
space.
protons
protein
rate
Photochemical
–
+
foc us
environmental factor
inuences
carbon
thylakoid
internet.
and
inuenced
The
the
of
PSI
from
electrons
happens
the
2
thylakoid
on
animations
instead
reaction:
2H
provides
superb
PSI.
+
which
Bioenergetics
NADP
.
water-splitting
The
catalysed
photophosphorylation
to
cannot
somewhere
is
NADP
Non-cyclic
Electrons
is
thylakoid
photophosphorylation
reaching
and
NADP
the
take:
Cyclic
of
of
of
1
is
A
TP
now
gradient ,
it
has
to
Part
travelling
give
a
which
impermeable
synthetase.
through
and
a
higher
lower
can
down
this
pH
now
protons
of
concentration
than
be
except
put
for
remarkable
their
the
to
inside
stroma.
work.
channels
protein
electrochemical
This
stage.
length)
the
is
inuence
an
Light
and
duration
(day
wavelengths
this
of
light
also
stage.
The
through
spins
as
gradient.
the
protons
As
the
Summary q uestions
protein
spins,
transferred
so
the
a
active
bond
site
forms
accepts
between
ADP
the
and
a
phosphate
terminal
ion.
phosphate
Energy
on
ADP
is
and
1
the
phosphate
ion.
This
is
a
phosphorylation
Explain
the
meaning
of
the
terms
reaction.
chloroplast pigment,
electron
carrier,
photosystem,
centre,
Z-scheme
reaction
electron
acceptor
electron
increasing
2
transport
Explain
the
difference
between
energy
chain
an
absorption
spectrum
and
an
levels
action
spectrum.
Name
the

electron
H
3
acceptor
pigments
main
and
chloroplast
explain
their
roles.
electron
transport

4
NADP
Explain
the
roles
of
the following
chain
in
reduced
the
light-dependent
stage:
‘energised’
photosystem
NADP
‘energised’
II,
photosystem
I,
X
electrons
NADP, ADP,
protons
(hydrogen
electrons
ions),
NADP
reductase, ATP
light
synthetase,
4H
water.
O
2
5
Three
separate
chloroplast
P700
suspensions
are
mixed
with
blue
photolysis
redox
dye
and
green
and
blue
illuminated
by
red,
e

4H
redox
light
e
2O
light. The
2
photosystem
dye
I
red
P680
pathway
of
electrons
in
non-cyclic
in
was
decolourised
light,
green
but
did
light.
not
in
blue
and
decolourise
Explain
these
photophosphorylation
results.
pathway
of
electrons
in
cyclic
6
Explain
how
a
light
intensity,
photophosphorylation
photosystem
II
b
X
site
of
proton
light
duration,
c
the
pumping
wavelength
the
Figure 1.5.1
and
of
light
inuence
light-dependent
stage
of
The Z-scheme shows the pathway taken by electrons in thylakoid
membranes. The energy levels of the compounds are plotted on this diagram with arrows
photosynthesis.
to show electron flow.
11
1.6
The
light-independent
The
Learning outcomes
products
supply
On
completion
should
be
able
of
this
section,
large
you
describe
the Calvin
series
reactions
cycle
as
the
stroma
as
independent

describe
enzyme

state
the

that
describe
occur
RuBP
in
the
the Calvin
roles
in
plant.
plants
Neither
need
for
functions
reactions
is
can
cannot
they
be
structural
such
as
necessary
to
be
stored
used
to
support,
catalysing
produce
as
a
build
long-term
up
the
information
reactions.
molecules
This
to
x
means
carbon
and
make
it
possible
to
produce
organic
molecules.
the
at
that

xation
of

reduction

carbon
the
diagram
of
the
Calvin
cycle
and
nd
the
three
main
occur:
carbon
dioxide
–
carboxylation
carbon xation
resynthesis
NADP
of
carefully
processes
of
a
metabolic
set
therefore
Look
light-
in
for
that
stage
in
carbon xation,
and
occur
reduced
role
light-dependent
the
stage
rubisco
reduction
RuBP
the
that
energy
and
further
and
of
the
molecules
storage
to:
a

of
of
stage
of
to
form
dioxide
regenerated
–
carbohydrates
acceptor
so
that
molecule
the
ribulose
reactions
are
bisphosphate
(RuBP)
is
cyclic.
cycle
of ATP
and
the Calvin

ADP
P
ATP
ATP
cycle
reduced

describe
the fate
of
triose
NADP
phosphate.
glycerate
reduction
3-phosphate
2
(3-carbon)
NADP
Link
Plants
use
the xed
carbon
to
make
triose
CALVIN
phosphate
carbon
the
groups
of
biochemicals
that
you
2
CYCLE
(3-carbon)
fixation
studied
in Unit
1:
–
carbohydrates,
carboxylation
lipids,
proteins
and
nucleic
acids.
ATP
CO
2
Regeneration
of
RuBP
ADP
hexose
S tudy
sugar
ribulose

foc us
(6-carbon)
bisphosphate
P
(5-carbon)
Why
bisphosphate? The
phosphate
groups
are
two
attached
to
starch
different
carbon
attached
would
be
to
the
called
atoms.
same
a
If
they
carbon
were
atom
diphosphate
(as
it
Figure 1.6.1
The Calvin cycle
in
Molecules
ADP).
diffuse
the
cell
the
chloroplast
The rst
product
of
a
3C
compound
the
they
cell
dioxide
air
dissolve
wall,
cell
envelope
do
this
are
(PGA).
tropical
dioxide
known
as C3
species
use
a
and
the rst
compound;
enters
compound
product
plants
such
as
is
and
maize
are C4
bond
related
to
their
in
in
and
where
intense
there
is
then
through
diffuse
the
stroma.
the
active
( r ubisco
site
for
of
ribulose
short)
bisphosphate
together
RuBP
.
A
carboxylation
with
reaction
the
occurs
is
formed
between
carbon
dioxide
in
and
which
one
of
a
the
RuBP
.
This
forms
forms
into
two
an
unstable
3-carbon
6-carbon
compounds
compound
known
which
as
is
the
acid
rst
(PGA)
or
product
of
glycerate
carbon
3-phosphate
(GP).
This
xation.
little
PGA
but
molecules
are
also
may
be
reduced
used
and
to
make
glycerol,
phosphorylated
amino
using
acids
reduced
and
NADP
dioxide.
A
TP
12
They
and
fatty
competition for
acids,
carbon
wall.
then
reach
hot
The
water
cell
cytosol
and
they
plants. This
survival
substance
temperatures
the
When
a
phosphoglyceric
is
in
and
stomata
sugar
immediately
cane
water
through
mesophyll .
different
carbons
4C
the
leaves
spongy
plants.
carbon–carbon
method
in
into
the
Plants
5-carbon
Many
in
membrane
into
carboxylase/oxygenase
that
diffuse
spaces
carbon xation
Carbon
is
carbon
surface
through
Did you know?
of
through
from
the
light-dependent
stage
to
make
triose
phosphate
(TP).
and
Module
TP
is
at
a
crossroads
of
pathways.
In
metabolism
as
it
may
enter
a
number
of

recycled
to
the
chloroplast
TP
may
converted
The
RuBP
into
hexose
phosphates
and
then
into
recycling
converted
into
fatty

converted
into
amino
molecules
produce
six
of
is
important
would
have
something
to
else.
example,
of
it
could
be
produced
acids.
triose
molecules
it
acids
from
12
RuBP
produced from
For
Of
of
otherwise
starch
be

foc us
be:
because

Bioenergetics
different
S tudy
metabolic
1
phosphate
RuBP
and
produced,
two
may
ten
be
of
used
these
to
are
used
produce
stored
waste
to
hexose
or
of
starch
in
starch
the
which
energy
the rst
used
would
to
be
a
make
place.
glycerol.
Environmental
conditions
influence
the
rate
at
which
the
Calvin
cycle
Did you know?
can
proceed:
Rubisco

Carbon
dioxide
concentration
–
if
the
carbon
dioxide
concentration
most
low,
then
the
rate
of
carboxylation
catalysed
by
rubisco
will
be

if
the
concentration
T
emperature
dependent,
stage
is
Calvin

slow.
Oxygen
with
will
be
triose
The
low
as
a
can
Calvin
the
cycle
rate
the
of
are
the
the
active
oxygen.
the
site
This
active
less
effect
Calvin
and
at
of
by
result
enzymes
xed
of
are
rubisco
means
site;
reduces
cycle
the
the
denatured
the
not
that
rate
At
at
only
oxygen
enzyme
carbon.
light
of
the
light
low
acts
so
2
Name
the
terms
but
less
It
active
or
inactive
as
a
in
the
dark. Oxygen
acts
competitive
inhibitor.
which
This
competes
as
carbon
of
the
the
and
of
are
in
energy
the
energy
turn
the
available
rate
to
cycle
carboxylation,
good
place
to
revise
the
enzymes from Unit
1.
is
so
is
supply
for
of
of
the
of
the
Calvin
drive
the
formation
cycle
of
high
light
intensity
low
light
intensity
GP
RuBP
RuBP
.
TP
intermediate
effect
results
the
The
a
of
dioxide
temperature,
NADP;
intensities
of
by
is
properties
an
of
compounds
changes
shown
in
in
the
these
in
the
reduction,
time
Calvin
environmental
graphs.
High CO
Low CO
2
concentration
2
concentration
RuBP
evitaler
Dene
light,
the
Summary q uestions
1
the
accepts
concentrations
temperature.
reduced
supply
recycling
and
The
and
poor
concentrations
influenced
intensity
low
a
are
optimum
A
TP
In
measured
investigated.
in
light-independent
produced.
stage.
and
Earth.
temperature
noitartnecnoc
factors
be
in
fastest
phosphate
relative
cycle
this
determined
on
evitaler
is
–
also
supplies
light-dependent
the
temperatures
produces
the
be
abundant
enzyme
Link
but
is
of
on
of
temperatures
high
most
higher
.
noitartnecnoc
TP
will
dependent
low
dioxide
and
enzymes
these
At
enzymes
active
stops.
dioxide
and
reactions
at
dioxide
carbon
carbon
The
the
concentration
oxygenase
xed
so
cycle
carbon
–
was
the
important
slower
is
than
is
is
optimum
GP
the
molecules
used
by
plants for
structural
support,
information
TP
storage
and
catalysing
reactions.
time
3
Name
the
three
main
stages
of
the Calvin
cycle
and
explain
the
importance
Figure 1.6.2
of
These graphs show changes
each.
in the concentration of three key
intermediate compounds in the Calvin
4
Explain
the
roles
of
the following
in
the
light-independent
stage:
RuBP,
cycle
rubisco,
PGA
and
5
State ve fates
6
Suggest
7
Explain
the
how
the
graphs
of
triose
the TP
oxygen
changes
in
phosphate
Figure
produced
acts
in
to
the
(TP).
in
reduce
the Calvin
the
rate
concentrations
of
of
cycle.
carbon xation.
PGA, TP
and
RuBP
as
shown
in
1.6.2.
13
1.7
Investigating
Rates
Learning outcomes
photosynthesis
of
plants.
On
completion
should

be
able
of
this
section,
There
how
effect
light

carbon
dioxide
to
investigate
intensity
dioxide

oxygen
of
rst
concentration
explain
why
control
variables
it
is
important
is
aquatic
investigated:
uptake
dry

mass
production
production.
two
of
T
o
these
are
measure
quite
carbon
difcult
dioxide
to
do
with
school
concentrations
or
you
college
need
gas
analyser
,
and
measuring
dry
mass
production
an
involves
how
to
calculate
rates
of
is
leaves
by
used
results.
and
at
weighing
relatively
terrestrial
off
photosynthesis from
experimental
of
intervals
during
the
day,
drying
them
to
taking
constant
to
it
explain
this
and
photosynthesis
mass

which
terrestrial
on
samples

in
in
and
infrared
rate
ways
investigated
the
apparatus.
the
three
be
you
The
carbon
are
may
to:
describe
of
photosynthesis
an
is
easy
plants.
aquatic
called
a
them
to
on
a
balance
measure
The
most
plant
such
oxygen
common
as
that
method
Elodea.
photosynthometer
reads
to
production
The
and
is
is
0.1
or
using
to
0.01 g.
either
collect
the
Luckily,
aquatic
gas
piece
of
apparatus
shown
in
Figure
or
given
commonly
1.7.1.
3
5
capillary
cm
syringe
plastic
tube
tubing
thermometer
Link
lamp
Think about why is it important to use
dry mass to measure the rate of
scale
air
(mm)
bubble
photosynthesis rather than fresh (wet)
shoot
of
Elodea
mass. Then try Summary question 1.
pond
water
beaker
Figure 1.7.1
of
water
A photosynthometer set up to determine the rate of photosynthesis of
Elodea
S tudy
foc us
This
It
is
most
important
that
you
can
be
used
to
investigate
the
effects
of
three
environmental
write
variables:
light
intensity
and
carbon
dioxide

concentration
talking
In
about
both
when
these
cases
we
writing
investigations.
are
light
dealing
The
light
resistor
with
lamp
quantitative
investigations
and
‘carbon
dioxide’
are
carbon

dioxide
concentration
temperature.

not
at
intensity
and
is
changed
changing
different
the
by
plugging
current
distances
from
flowing
the
in
to
plant.
the
the
The
lamp
to
a
lamp,
or
by
actual
variable
light
putting
the
intensity
can
‘light’
be
and
intensity
or
measured
with
a
light
meter
or
,
if
the
distance
is
varied,
by
calculating
correct.
2
where
1/d
S tudy
S tudy
d
=
the
distance
between
lamp
and
plant.
foc us
foc us
Notice
these
instructions
refer
to
‘gas
collection’
rather
than
‘oxygen
2
Why
is
front
it
of
1/d
a
?
Put
light
a
piece
source
so
of
the
card
in
light
collection’. The
also
contains
gas
that
other
collects
gases,
such
is
as
not
pure
carbon
oxygen from
dioxide,
that
photosynthesis;
come
out
of
it
solution.
2
covers
away
an
so
area
light
1
is
cm
.
Move
‘spread
the
out’
card
over
a
Carbon
larger
area.
Double
the
of
the
source;
light
is
now
dioxide
concentration
is
changed
by
making
up
a
series
of
solutions
distance from
‘spread
sodium
hydrogencarbonate.
This
dissolves
in
water
to
form
out’
–
hydrogencarbonate
2
over
4 cm
2
)
of
original
the
light
of
distance,
passing
original
14
1 cm
which
diffuse
into
cells
and
into
twice
the
is
intensity.
a
to
form
carbon
dioxide,
which
is
then
xed
in
the
Calvin
cycle.
intensity
through
a
single
2
square
),
(HCO
3
squares. At
chloroplasts
the
ions
2
(=
quarter
of
the
T
emperature
is
thermometer
changed
checks
appropriate.
It
tube
the
next
to
is
the
best
to
plant.
by
adding
hot
temperature
take
the
and
and
cold
hot
temperature
water
and
of
to
cold
the
the
water
water
water
in
are
the
bath.
added
A
as
boiling
Module
Several
1
precautions
Exclude
light
need
from
to
be
other
taken:
only
source
of
light
sources.
is
the
It
is
lamp.
best
to
When
cover
the
windows
investigating
one
so
these
light
intensity,
the
other
two
variables,
carbon
dioxide
investigations
must
be
kept
the
to
identify
Over
time
the
plant
uses
up
be
the
the
independent
dependent
variable,
the
same.
derived
2
should
and
variable,
temperature,
you
variable,
able
e.g.
Bioenergetics
Link
In
the
1
the
carbon
dioxide
(it
is
a
raw
variable
and
the
controlled
material)
variables.
and
so
much
plant
the
of
is
3
an
effect
kept
decrease
of
concentration
in
if
the
up,
gas
so
time
it
for
all
emerges
is
a
best
plant
and
use
to
few
probably
are
carbon
prevent
the
going
to
dioxide
plant
does
be
not
have
taken,
but
if
concentration
maintaining
the
the
may
same
rate
time.
the
a
This
results
solution
the
from
to
a
same
signicantly
photosynthesis
Most
only
decreases.
end
freshly
become
of
the
cut
stem
piece
adjusted
to
of
the
and
this
Elodea.
may
It
seal
Distance from
Length of
Length of time
lamp to
gas
for
takes
conditions
and
plant/
a
constant
conditions
volume
of
become
Elodea,
4
Best
bulb
is
gas
the
pulled
therefore
are
the
photosynthesis
It
and
may
case
they
of
that
the
capillary
tubing.
to
in
the
The
pulled
length
of
it
65
180
75
43
120
100
50
200
150
28
210
200
10
200
has
pieces
inside
syringe
After
so
50
of
mass.
just
tubing.
is
collect/seconds
the
when
same
mm
of
different
stem
The
set
record
use
the
the
tubing.
plunger
each
to
readings
have
putting
water
the
for
idea
take
should
by
is
time,
good
necessary
capillary
there
of
a
only
be
obtained
end
so
is
produced
length
lls
of
which
results
at
rate
It
constant.
in
known
gas
used.
gas to
to
mm
reach
bubble/
plunger
a
that
bubble
the
250
5
250
any
At 30 °C and at an intermediate carbon dioxide
is
concentration
measured
5
Repeat
with
the
readings
scale
should
and
be
recorded.
taken
and
a
mean
Concentration of
value
calculated.
Results
should
be
sodium
Length of
hydrogencarbonate
critically
to
see
if
any
are
gas
Length of time for
scrutinised
anomalous.
If
bubble/mm
gas to
collect/
so,
–3
solution/g dm
they
the
should
mean.
not
be
Results
used
can
in
the
then
be
calculation
plotted
on
seconds
of
a
0
5
350
5
30
10
55
200
15
63
180
20
75
210
graph.
The
tables
have
results
from
two
investigations.
210
At 30 °C with a lamp at a distance of 75 mm
Summary q uestions
1
Explain why rates of photosynthesis should be determined
4
Use
the
results
in
the rst
table
to
present
a
new
table
2
by using changes in dry mass, not fresh mass.
of
data
rates
2
Explain fully
a
why
it
is
important
to
that
of
carbon
dioxide
concentration
and
constant
independent
repeat
when
variable
readings
each
under
should
be
of
these
is
not
investigation,
Plan
an
investigation
b
why
5
taken.
to nd
out
how
light
Plot
on
plant.
a
Include
method
an
the
as
a
rate
rates
presented
of
photosynthesis
the following
set
explanation
how
of
of
of
in
how
the
a
will
will
be
intensity
addition
(as
to
1/d
the
)
and
the
information
a
rate
to
of
show
the
effect
of
light
photosynthesis.
Repeat
the
second
table
plot
a
steps
to
in
question
construct
graph
to
show
a
4
using
revised
the
effect
the
table
of
results
of
of
the
results
on
the
rate
of
carbon
dioxide
photosynthesis.
aquatic
prediction;
precautions;
be
graph
intensity
an
plan:
points;
results
photosynthesis
on
your
numbered
of
a
the
concentration
inuences
in
the
and
and
3
light
light
intensity
intensity
the
keep
provided.
temperature,
shows
photosynthesis
collected;
calculated
6
Suggest
why
all
the
photosynthometer
than
the
true rate
results
obtained
measure
of
the
with
apparent
a
rate
rather
photosynthesis.
and
graph.
15
1.8
Limiting factors
If
Learning outcomes
you
on
On
completion
state
able
section,
you
the
like
to:
the factors
that
ruoh

be
this
a
rate
the
photosynthometer
of
one
photosynthesis,
in
Figure
to
investigate
the
graph
the
that
effect
you
of
might
light
intensity
expect
inuence
of
D
O
rate
photosynthesis
dene
the

the
term
context
describe
of
and
intensity,
limiting factor
explain
carbon
concentration
the
how
light
dioxide
and
rate
temperature
of
explain
how
a
knowledge
limiting factors
is
used
to
C
10
B
5
A
0
etar
photosynthesis

15
fo
inuence
in
photosynthesis
20
mc/sisehtnysotohp
3

look
25
2
the
will
1.8.1.
1
should
of
use
of
500
1000
light
1500
intensity/arbitrary
2000
units
of
photosynthesis
improve
0
Figure 1.8.1
Graph that shows the effect of light intensity on the rate of photosynthesis
crop
Y
ou
may
be
asked
to
describe
a
graph
like
this.
Before
writing
an
answer
,
production.
read
on
the
the
introduction
axes.
In
independent
S tudy
foc us
which
Look
Notice
that gures
are
given
on
should
quote
in
any
exam
a
paper
description
numbers
ruler
and
very
to
rule
read
of
only
off
carefully.
allow
±
1
when
the
intensities.
lines
on
line
very
intensity
dependent
by
on
is
carefully
plotted
variable
measuring
the
graph,
is
the
and
on
the
x-axis
rate
volume
which
highlight
the
of
of
shows
as
labels
is
the
photosynthesis,
oxygen
the
the
it
rate
collected.
at
different
an
It
does
inflection
not
and
start
then
a
at
the
origin;
‘plateau’.
there
There
is
are
a
‘slope’,
four
then
regions,
will
When
Examiners
square
call
A
to
D,
and
these
are
described
and
explained
in
the
which
table.
the
the
small
is
a
explaining
‘slope’
because
intensity
the
relationship
light
and
intensity
the
rate
is
shown
the
in
the
graph,
determining
increases.
The
plateau
realise
factor
.
that
there
Increase
shows
that
the
is
the
rate
or
remains
less
The
determined
at
question
light
the
light
may
been
the
these
we
graph. Use
variable.
carefully
there
accurately
to
case
both
light
axes. You
has
this
constant;
an
increase
in
the
light
intensity
does
not
lead
to
any
marking.
further
increase
so
it
that
carbon
the
it
the
not
dioxide
rate
The
does
in
rate.
increase
Some
any
concentration
must
be
explanations
some
given
more.
or
,
other
above
other
if
factor
This
must
could
increasing
be
be
these
restricting
temperature
two
does
not
the
rate
or
increase
factor(s).
can
be
made
much
more
concise
by
using
1
the
25
term
limiting
ruoh
increasing
O
2
regions
B
is
a
and
factor .
limiting
C
Any
factor
.
because
any
environmental
Light
intensity
increase
leads
factor
is
to
the
an
that
prevents
limiting
increase
the
factor
in
rate.
rate
in
Light
20
mc/sisehtnysotohp
3
intensity
with
the
is
not
the
increases
limiting
in
light
factor
in
intensity.
region
The
D
as
other
the
two
rate
does
variables
not
have
increase
been
15
kept
constant,
rate.
If
so,
so
they
maybe
are
the
increasing
limiting
one
factors
or
in
other
of
region
them
D.
will
Further
increase
the
experiments
10
are
necessary.
Figure
1.8.2
shows
the
effect
of
carbon
dioxide
concentration,
the
shape
5
fo
of
etar
If
the
no
graph
carbon
is
very
similar
.
dioxide
is
provided
there
can
producing
some
carbon
be
no
photosynthesis.
However
,
0
0
200
CO
400
600
concentration/parts
800
per
1000
million
2
the
will
As
Figure 1.8.2
be
the
respires,
used
up
so
immediately
concentration
by
increases
chloroplasts
the
rate
can
dioxide,
so
there
increase
but
is
so
any
no
gas
that
at
produced
exchange.
50ppm
Graph that shows the effect
of carbon dioxide concentration on the
rate of photosynthesis
16
plant
is
equal
to
the
rate
photosynthesis
is
of
respiration.
greater
than
Above
rate
of
50ppm
the
respiration
so
rate
of
excess
oxygen
it
Module
S tudy
Look
at
Bioenergetics
foc us
your
Region
1
answer
to
Summary
Light
question
6 from
1.7
in
this
module
Description
while
reading
this
table.
Explanation
intensities
A
0–100
No
oxygen
apparent
has
rate
been
of
released;
the
photosynthesis
All
=
0
the
the
oxygen
plant
in
surroundings
B
100–250
Rate
of
photosynthesis
proportional
C
250–1250
Rate
of
to
the
photosynthesis
increase
but
less
is
light
Light
intensity.
continues
to
to
1250–2000
Rate
of
photosynthesis
is
constant.
Light
than
diffuses
there
out
is
a
limiting
of
the
‘slope’,
factor
concentration
for
A
TP
and
increases
plateau
factor
as
it
is
means
reduced
and
more
because
and
leaves
a
is
that
raw
NADP
.
oxygen
collected.
carbon
material
rubisco
carbon
other
and
meaning
can
The
is
such
the
the
of
the
in
and
cycle.
there
is
photolysis
temperature
is
no
and
of
a
photosynthesis
be
is
not
released
is
to
used
by
the
collected.
increasing,
are
beginning
as
same
intensity
light
providing
more
energy
to
increasing
limit
light
the
rate
intensity
of
is
not
effect.
has
energy
no further
limit
the
effect; factors
rate
of
other
photosynthesis.
increases
the
greater
the
need
stage
water
.
longer
light
is
the
Increasing
light-dependent
concentration
as
concentration
concentration
Calvin
faster
produced
dioxide
factors,
for
work
rate
As
dioxide
is
photosynthesis
having
D
cannot
by
and
chloroplasts.
Other factors
steeply.
so
intensity
the
produced
respiration
There
the
is
a
limiting
intensity,
are
limiting.
Photosynthesis
of
protected
countries
is
a
crops
have
major
(e.g.
fully
factor
in
tomatoes,
automated
crop
production.
lettuce
and
glasshouses
Farmers
cucumber)
in
and
growers
temperate
that:
Summary q uestions

control
light
intensity

control
temperature
with
articial
lighting
and
shading
1
with
heaters
and
Dene
the
terms
limiting factor,
ventilation
apparent rate of photosynthesis ,

enrich
the
carbon
dioxide
concentration
by
burning
hydrocarbons
(e.g.
true rate of photosynthesis.
propane)

supply
water
direct

supply
mineral
to
the
roots
or
by
using
direct
to
roots
2
sprinklers
Describe
and
obtained for
nutrients
at
the
to
the
growth
stage
of
the
the
Caribbean,
growers
use
plastic
and
mesh
greenhouses
to
conditions.
Plastic
protects
against
heavy
rain
and
the
5
mesh
intensities
against
used,
insect
so
that
pests,
reducing
costs
so
of
salad
crops
reducing
watering
are
costs
as
not
of
scorched.
pesticides.
water
is
Both
Drip
supplied
also
of
eld
crops
such
as
cereals,
to
sugar
cane,
soya,
yams
page
how
such
are
not
able
to
do
much
about
4
carbon
dioxide
15.
growers
as
the
is
melons
also
and
of
tomatoes,
cucumbers
glasshouses
plants.
of
can
in
prevent
photosynthesis
the
of
these
and
plants from
cassava,
you
protect
irrigation
direct
on
Explain
rate
Growers
that
questions
reduces
crops
light
Summary
control
3
the
graphs
results
crop.
and
In
the
the
concentrations
drew from
appropriate
explain
being
limited
by
concentration,
environmental factors.
light
intensity
drainage
apply
can
or
sow
each
activities
of
temperature.
ensure
fertilisers
also
shade
to
to
their
other
.
that
water
ensure
crops
All
not
mineral
at
an
farmers
competitors
However
,
is
a
nutrients
optimum
and
(weeds),
they
can
limiting
not
density
growers
pests
do
take
and
provide
factor
so
for
limit
the
steps
irrigation
growth,
growth.
plants
to
do
reduce
and
and
They
not
the
4
Discuss
and
the
steps
growers
take
their
to
in
that farmers
the Caribbean
maximise
the
yields
can
of
crops.
diseases
17
1.9
Practice
Energy
Answers to
all
The following
questions
For
practice
questions,
see
the CD
will nd
choice
and
exam-style questions
questions.
advice
about
questions
are
in
in
the
and
photosynthesis
be found on the
of
questions:
accompanying CD.
c
examination
The
multiple-choice
accompanies
analysing
in CAPE
can
style
answering
that
exam-style
this
water
book. You
answering
Biology Unit
a
Outline
the
processes
photosynthesis
that
was
multiple-
of
light
spectrum
readings from
the
light
the
light-dependent
the
light-independent
a
of
the gures for
calculated from
the
the
sensor.
[1]
occur
What
conclusions
absorption
in
can
spectrum
be
made from
and
the
action
the
spectrum
in
the gure?
ii
how
a ask
1.
during:
i
Describe
how
were
stage
[6]
stage.
5
The
diagram
[2]
shows
the Calvin
chloroplast
is
cycle.
[4]
enzyme
b
through
100%. Suggest
absorption
d
1
transmission
adapted
to
A
carry
6CO
2
out
2
a
photosynthesis
efciently.
[5]
6
Describe how a leaf of a dicotyledonous plant is
adapted to carry out photosynthesis efciently.
ribulose
bisphosphate
12
(RuBP)
molecules
of
[5]
6 ADP
b
Explain
what
is
meant
by
the
term
B
12 ATP
limiting factor
1
as
c
applied
Explain
of
to
how
photosynthesis.
a
knowledge
photosynthesis
is
of
applied
6 ATP
[5]
12 ADP
limiting factors
to
increase
the
6
production
of
crop
plants.
ribulose
phosphate
(RuP)
[5]
4
2
3
a
Explain
why ATP
is
described
as
the
‘universal
3
energy
b
currency’.
Describe
how ATP
C
[5]
is
produced
during
a
photosynthesis.
i
Name
enzyme
A,
substance
substances formed
c
Explain
and
one
of
the
at
C.
[3]
why:
i
carbon
ii
light
are
B
[5]
dioxide
concentration,
ii
State
the
iii
Name
iv
State
source
of ATP.
[1]
and
intensity
the
precise
site
of
the Calvin
cycle.
[2]
[5]
limiting factors for
the
number
of
carbon
atoms
in
ribulose
photosynthesis.
bisphosphate.
4
Investigations
of
the
were
unicellular
wavelengths
suspension
measured
was
and
the
a
carried
alga,
passed
light
light
out
using
Chlorella.
through
sensor
b
suspension
of
a ask
behind
transmitted
a
Light
the
of
the
c
the ask
through
middle
of
the
oxygen
sensor
suspension.
was
Results
Discuss
the
carriers
in
placed
in
to
plot
an
absorption
obtained
spectrum
as
shown
roles
and
an
the
i ATP
NADP
ii
vi
proton
light
roles
iii
of
600
The
rate
using
b
Explain
used
18
to
how
plot
electron
[6]
the following
a
in
iv
photosynthesis:
carotene
v
carbon
RuBP
vii
rubisco
viii
ATP
synthetase
[12]
of
photosynthesis
discs
cut from
can
Coleus
be
determined
leaves. The
discs
placed
in
a
tube
and
had
all
the
air
removed.
of
When
placed
into
a
tube
of
dilute
solution
they
sodium
all
sank
to
the
700
leaves
were
kept
in
the
dark
and
at
light/nm
intervals
is
and
and
pumps.
bottom. The
what
pigments
chlorophyll
hydrogencarbonate
spectrum
[2]
absorbed
photosynthesis
Explain
in
of
were
rate
a
shown
below.
by
wavelength of
reactions
action
7
500
the
cycle.
were
percentage
400
of
of
a
photosynthesis.
Discuss
ix
spectrum
advantage
the
dioxide
used
the
diagram forming
the
6
suspension. An
Explain
different
[1]
meant
by
the
terms
absorption
action spectrum.
results from
the
action
the
oxygen
spectrum.
light
[2]
sensor
were
[2]
some
were
intensities. The
to oat
was
with freshly
results
are
removed
time
in
discs
the
at
table.
a
placed
taken for ve
recorded. The
cut
and
of
investigation
lower
in
different
the
was
discs
repeated
temperature. All
the
Module
Distance of
Time taken for
Time taken for
Relative
lamp from
ve discs to
ve discs to
intensity
oat
oat
leaf
discs/mm
at
30 °C/
at
seconds
50
125
275
100
210
390
150
360
410
200
600
620
250
none
of
discs
rose
to
the
surface
a
Explain
tube
b
why
and
the
why
Describe
and
discs
to
the
none
of
discs
rose
bottom
the
at
The
to
indicator
hour
0.33
0.06
yellow
0.43
0.
16
orange
0.50
0.40
red
0.57
0.80
magenta
0.67
1.60
purple
0.73
the
of
the
c
Explain
d
i
the
results
shown
in
the
table.
[7]
[5]
trend
shown
by
the
Explain
the
advantage
of
using
a
colorimeter
discs
30 °C.
leaf
1
yellow
(darkness)
taking
the
results.
[2]
[3]
ii
c
after
Absorbance
for
kept
solution
the
they oat.
explain
Hydrogencarbonate
Colour
0
surface
sink
Bioenergetics
20 °C/
seconds
the
light
1
discs
left
in
the
dark
remained
on
Suggest
how
this
investigation
could
be
the
improved.
bottom
of
the
tube.
Explain
why
they
did
oat.
d
[3]
Explain
longer
why
the
to oat
leaf
than
discs
kept
those
at
at
20 °C
took
9
A
student
the
30 °C.
[3]
A
concentrated
culture
of
the
unicellular
used
effect
rate
of
were
8
[2]
not
of
a
photosynthometer
carbon
dioxide
photosynthesis.
placed
into
was
made
into
This
by
was
mixing
then
it
with
dripped
a
solution
into
a
of
sodium
solution
of
alginate forms
into
trapping
indicator
table
shows
treated
the
with
pH
the
solution
buffer
When
Beads
tubes
of
solution
solutions
air
it
red
of
is
in
obtained
different
were
into
intensity/
1
hour
removed
solution
and
and
was
the
the
placed
Suggest
the
results
using
are
advantage
the
a
beads
in
this
of
a
suspension
of
six
light
the
3
Mean
0
5
0
0
0
10
7
9
5
20
17
15
13
30
27
36
23
40
32
31
33
test-
Look
critically
at
the
results
and
identify
any
intensities
beads
b
with
within
rather
results.
[1]
were
Copy
and
mean
a
light
table.
algae
investigation
the
2
0
complete
length
of
gas
the
table
bubble
by
calculating
collected for
the
each
intensity.
[3]
the
diameter
of
the
capillary
tubing
in
the
than
photosynthometer
using
bubble/mm
the
indicator
in
using
gas
0
The
jelly-like
Length of
purple
colorimeter
shown
table.
solution. The
recorded. The
of
a
9.2
into
different
absorbance
determined
green lter. The
a
colours
in
units
anomalous
for
sodium
colour.
hydrogencarbonate
placed
of
recorded
pH.
through
in
collected
0
a
test-tubes
oxygen
1
when
magenta
red
student
pH. The
8.8
bubbled
becomes
of
Hydrogencarbonate
red
solution. The
jelly-like
changes
8.4
S. q uadricauda were
the
to
colours
orange
atmospheric
of
of
8.0
yellow
indicator
inside.
sensitive
range
7
.6
Colour
algae
is
concentrations
the
plant
calcium
arbitrary
beads,
on
aquatic
alginate.
Light
chloride. Calcium
an
small
the volumes
beads
of
alga
hydrogencarbonate
Scenedesmus q uadricauda
investigate
concentration
Pieces
different
to
algae.
was
1.0 mm.
[2]
3
c
b
Calculate
the
rate
of
photosynthesis
in
mm
–1
min
Suggest:
for
i
three variables
this
ii
a
that
investigation
suitable
control.
should
be
controlled
each
light
intensity
and
add
to
the
table.
[3]
in
d
Plot
a
graph
e
Explain
of
the
results.
[5]
[3]
[1]
the
student’s
results.
[6]
19
1
Bioenergetics
2.
1
Introduction
Learning outcomes
to
Cellular
respiration
molecules
On
completion
should
be
able
of
this
section,
you
seen,
state
that
chemical
in
cellular
energy
compounds
chemical
is
in
respiration
organic
transferred
energy
transferred
that
as
in ATP
for
state
that
of
Protein
to
and
than
is
the
is
transfer
available
form
the
molecules
may
is
of
for
chemical
cells
in
a
energy
useable
from
form.
organic
As
we
have
A
TP
.
protein
The
a
in
as
a
their
repair
diet
that
in
than
can
be
of
order
are
store
source
growth,
energy
oxidised
molecules
short-term
used
for
are
These
are
be
required
more
heat
cellular
organic
is
it
synthesis.
Carbohydrates
of
energy.
energy
and
that
energy
carbohydrates,
if
Fats
present
replacement.
herbivores,
harnessed
as
are
in
made
larger
diet
these
available
and
long-term
fats.
stores.
quantities
Carnivores
their
from
is
proteins
respire
consists
mostly
compounds
is
of
shown
respiration
in
involves
that
useable
organic
A
TP
meat.

so
to:
The

respiration
stepwise
molecules,
the
table.
breakdown
each
step
–1
Respiratory
catalysed

name
by
the four
respiration

an
outline
of
the
stages
carbohydrates,
of
differences
and
Energy/kJ
g
e.g.
starch,
glycogen,
glucose,
sucrose
and
16
lactose
glucose
between
lipids,
aerobic
substrate
enzyme
e.g.
triglycerides
39
anaerobic
respiration.
proteins
The
17
oxidation
coenzyme
S tudy
cell,
foc us
so
they
respiration
breakdown
occurs
of
inside
confuse
it
onwards
we
the
organic
all
with
respiration
is
chemical
molecules
living
cells.
breathing.
will
refer
simply
as
to
Do
that
not
From
now
from
of
create
chain
ADP
cellular
respiration.
reduced
series
a
of
form
is
to
in
nal
required
the
split
whole
of
just
are
electron
to
is
coupled
these
oxidised
of
same
to
acceptor
the
reduction
available
recycled.
is
as
and
protons.
the
This
in
in
the
the
in
of
the
each
happens
in
Hydrogens
Electrons
intermembrane
called
involved
way
be
and
into
carriers
is
with
molecules
phosphorylation .
electrons
moved
gradient
the
of
oxidative
pathway
of
few
into
protons
proton
A
TP
substrates
very
continually
are
The
The
are
process
and
products
is
so
be
the
NAD
the
the
Oxygen
water
There
gradient.
Oxygen
one
in
carriers
(ETC).
to
respiratory
have
mitochondria
Cellular
of
NAD.
electron
pass
to
space
a
to
transport
phosphorylation
of
photosynthesis.
on
being
reduced
it
forms
water
,
respiration.
respire
process
glucose
is
completely
aerobic
to
respiration .
carbon
If
dioxide
oxygen
is
and
not
Link
Remind
yourself
about
the
available,
respiration
processes
that
roles
of ATP.
See
pages
this
process
oxygen
Instead
with
Link
is
it
the
an
adjective
that
‘requiring
air’,
but
in
refers
to
requiring
the
See
aerobic
20
page
and
36 for
a
but
without
NAD
is
the
recycled
use
in
a
of
the
different
anaerobic
way
respiration
available
as
the
of
ethanal
then
electron
pyr uvate
acceptor
lactate.
that
acts
In
as
plants
an
does
in
not
enter
animals
and
fungi
electron
and
(e.g.
acceptor
mitochondria.
some
bacteria,
yeast)
to
it
is
produce
ethanol
dioxide.
is
therefore
common
to
both
aerobic
and
anaerobic
respiration.
Biology
oxygen
link
reaction,
Krebs
in
comparison
anaerobic
to
carbon
aerobic
air.
continue
literally
The
it
is
formation
Glycolysis
means
not
acts
converted
and
is
still
mitochondria.
4–5.
If
‘Aerobic’
can
in
structure
and
and
occur
of
respiration.
respiration
only.
cycle
and
oxidative
phosphorylation
occur
in
Module
Before
starting
to
learn
the
details
of
respiration,
make
sure
that
you
outline
The
of
the
intermediate
metabolic
route
acids.
In
compounds
the
pH
of
in
body
Krebs
fluids
cycle
and
and
some
cytoplasm
in
glycolysis
they
all
exist
are
that
are
named
using
the
sufx
is
to
we
this
cellular
is
look
Respiration
by
an
is
at
the
pathways
respiration
a
enzyme.
chemical
Breathing
and
of
is
and
gas
it
in
breathing
consisting
exchange
or
of
are
detail,
gas
remember
that
makes
hydrogen
physical
is
better
it
sound
as
if
it
accepts
each
catalysed
processes.
foc us
(6C)
To
help
you
respiration,
ADP
phosphate
(6C)
onto
you
ATP
a
biphosphate
learn
copy
large
read
adding
ADP
fructose
it
acceptor,
exchange.
reactions,
ATP
glucose
carrier;
hydrogen
permanently.
S tudy
glucose
a
‘–ate’.
respiration
not
process
hydrogen
call
which
Before
a
as
not
anions
foc us
map.
NAD
organic
Bioenergetics
have
S tudy
the
1
the
the
sheet
the
rest
details
‘route
of
of
information
paper
this
to
of
map’
and
as
chapter
keep
it.
(6C)
S tudy
2ADP
foc us
NAD
You
2ATP
need
information
about the
reduced
structure of fat
molecules to
be
able
NAD
to
answer Summary question
4
in full.
pyruvate
glucose
pyruvate 
glycolysis
NAD
Summary q uestions
acetyl
reduced
link
pyruvate

coenzyme A
NAD
reaction
1
Explain
briefly
what
cellular
coenzyme A
respiration
CO
is for.
2
2
acetyl
a
List
coenzyme A
of
coenzyme A
b
the
State
reduced
stages
of
respiration
glucose.
where
in
the
cell
they
occur.
citrate
(6C)
NAD
NAD
3
Use
your
answers
to
question
2
NAD
to
reduced
NAD
Krebs
make
stages
a
of
table
showing
respiration,
the four
the
precise
cycle
sites
CO
in
the
cell
where
they
occur,
2
the
molecule
at
the
start
of
the
reduced
stage
FAD
and
the
end
products.
NAD
FAD
4
Explain
why
1 g
of fat
yields
more
reduced
energy
CO
in
1 g
of
ADP  Pi
What
are
respiring
6
hydrogen
Suggest
NAD
and
FAD
the
advantages
glucose
why
rather
marathon
of
than fat?
runners
carriers
take
(reduced
than
sugar.
5
reduced
respiration
NAD
2
ATP
are
sports
drinks
during
their
oxidised)
oxygen
event.
oxidative
phosphorylation
water
7
ATP
Figure 2.1.1
ADP  Pi
The metabolic ‘route map’ of respiration. Keep looking back to this as you
Suggest
why
excreted
pyruvate
when
is
animals
not
respire
anaerobically.
work your way through the next few pages.
21
2.2
Glycolysis
The
Learning outcomes
purpose
‘hub’
On
completion
should
be
able
of
this
section,
of
been
you
protein.
breakdown

state
that
glycolysis
metabolic
glucose

to
describe
steps

state
pathway
in
is
that
explain
converts
the
end
In
of
is
the
the
prepare
Krebs
blood,
plants,
sucrose
to
cycle.
broken
glucose
(see
page
may
74)
glucose
In
have
the
animals,
down
or
for
from
been
central
glucose
glycogen
obtained
metabolic
may
or
from
the
starch.
In
glycolysis,
some
is
NAD
at
Figure
products
some
‘held’
a
as
later
energy
reduced
stage.
is
transferred
NAD.
No
The
carbon
from
energy
dioxide
is
glucose
is
directly
transferred
formed
during
as
from
A
TP
reduced
2.2.1
shows
more
complex,
main
points
the
with
main
more
steps
of
glycolysis.
intermediate
The
compounds
metabolic
than
pathway
shown
here.
that
you
need
to
know
are
described
on
the
opposite
cell
page.
surface
membrane
molecule
Link
glucose
formula
of
α
of
the
structural
glucose from Unit
1.
glycogen
See
1.3
in
Module
A
1.
glucose
ATP
S tudy
foc us
B
ADP
Copy
onto
out
a
the
large
glycolysis
sheet
of
pathway
paper.
glucose
Make
6-phosphate
(6C)
ATP
C
drawings
of
the
simplied
structural
ADP
formulae
of
glucose,
the
fructose
intermediates
and
Question
page
1
on
pyruvate,
38
to
1,6
bisphosphate
(6C)
using
help
you.
D
triose
triose
phosphate
phosphate
P
NAD
P
NAD
E
reduced
NAD
reduced
3C
intermediate
3C
bisphosphate
NAD
intermediate
bisphosphate
ADP
ADP
F
ATP
ATP
Link
3C
intermediate
3C
phosphate
There
is
more
about
carrier
intermediate
phosphate
proteins
ADP
for
glucose
on
page
ADP
104.
F
ATP
ATP
pyruvate
(3C)
pyruvate
(3C)
Link
Figure 2.2.1
What
There
are
nine
glycolysis,
specic
to
use
reactions
catalysed
enzyme;
you
by
should
be
See
different
3.
1
in
enzymes
Module
is
needed
for
glycolysis
to
occur?
in
a

a
substrate

a
pool

A
TP

nine

NAD.
–
glucose,
glycogen
or
starch
–
rich
in
energy
able
knowledge from Unit
why
needed.
22
each
your
explain
different
The main stages of glycolysis in an animal cell
1
of
phosphate
ions
to
are
different
1.
enzymes
(there
are
nine
steps
in
glycolysis)
is
The
of
carrier
yourself
and
glycolysis.
glycolysis.
Remind
have
converted
main
glycolysis
the
which
from
is
the
pyruvate
and
glycolysis
cell
absorbed
from
to:
the
of
Module
Animal
the
cells
situation
Sucrose
surface
steps
in
is
carrier
diffusion
plant
cells
broken
the
is
and
glycolysis
proteins
of
down
membrane
Follow
A
have
facilitated
in
glucose
different
in
is
the
the
from
as
cell
wall
and
surface
sucrose,
hydrolysed
pathway
cell
tissue
or
in
read
it
the
fluid
not
membrane
into
the
glucose
passes
is
though
to
cell.
1
Bioenergetics
allow
The
transported.
the
cell
cytoplasm.
these
descriptions
of
the
following
carefully.
Glucose
enters
membrane.
the
cell
Glucose
is
by
facilitated
either
stored
diffusion
as
through
glycogen
or
the
enters
cell
surface
glycolysis
immediately.
Phosphorylation
B
Glucose
is
phosphorylated
to
glucose
6-phosphate;
this
maintains
the
Link
steep
C
diffusion
gradient
for
glucose
Glucose
is
phosphorylated
again
Glucose
is
phosphorylated
because
very
reactive.
T
wo
molecules
of
to
to
continue
form
fructose
although
A
TP
are
entering
it
used
is
in
the
cell.
One
bisphosphate.
energy-rich
steps
B
it
and
is
not
of
raise
the
roles
energy
of ATP
levels
(see
in
cells
page
is
to
5).
C
Lysis
S tudy
D
Fructose
(TP).
bisphosphate
This
is
lysis.
is
Note
split
that
into
the
two
molecules
reactions
after
of
triose
lysis
occur
twice
for
E
each
molecule
of
foc us
phosphate
is
the
most
important
glycolysis
from
Oxidation
the
as
it
conserves
substrate,
phosphorylation.
E
Energy
from
the
two
molecules
of
TP
is
transferred
as
it
dehydrogenated.
In
this
reaction
the
oxidation
of
TP
is
linked
happens
Energy
of
which
NAD.
would
phosphorylation
of
Hydrogen
be
TP
atoms
transferred
using
as
transfer
heat
phosphate
is
ions
from
TP
conserved
from
the
using
it for
Remember
to
by
twice for
that
every
with
molecule
reduction
in
energy
is
this
the
reaction
glucose.
of
glucose
that
is
respired.
NAD.
the
pool
in
the
Link
cytosol.
Reduced
oxidative
NAD
may
phosphorylation
be
or
used
may
in
be
the
used
production
in
other
of
A
TP
in
reactions.
Some
are
Substrate-linked
ADP
and
the
3C
the
enzyme
and
intermediate
one
of
the
bisphosphate
phosphate
occupy
groups
is
the
active
transferred
to
site
ADP
3C
A
TP
.
This
is
intermediate
pyruvate
and
of
is
glycolysis
how
repeated
on
phosphate
another
A
TP
the
and
active
ADP
site
react
of
to
another
give
the
enzyme
end
as
respiration
lactate
is
of
back
into
glucose
(see
to
page
form
which
anaerobic
converted
an
reactions
phosphorylation
from
F
of
reversible,
33).
the
product
molecule.
S tudy
foc us
Summary q uestions
Read
these
carefully
1
Explain
2
Nine
what
glycolysis
many
3
enzymes
enzymes
Describe
what
4
List
5
What
the
happens
6
State
products
happens
the ATP
lysis,
of
to
a
produced
why
catalyse
involved
phosphorylation,
Figure
pages
list
the
again
three
very
different
is for.
products
different
two
and
and
in
not
each
the
reactions
just
of
oxidation,
of
glycolysis. Why
are
so
answer
of
glycolysis
Summary
so
you
question
can
4.
one?
the following
stages
substrate-linked
of
glycolysis:
phosphorylation.
glycolysis.
the ADP formed
in
in
the rst
two
steps,
B
and C,
and
b
glycolysis?
2.2.
1
shows
glycolysis
in
an
animal
cell
and
not
in
a
plant
cell.
23
2.3
The
mitochondrion
The
Learning outcomes
mitochondrion
occurs.
On
completion
should
be
able
of
this
section,
you
Glycolysis
glucose.
Pyruvate
transferred
to:
is
state
that
the
mitochondrion
site
of
aerobic
describe
the
own
The
is
not
energy-rich
by
the
reduced
in
efcient
and
the
three
NAD
which
at
rest
of
of
respiration
releasing
chemical
stages
from
the
energy
energy
that
respiration
glycolysis
is
also
that
a
from
can
be
occur
source
in
of
and
it
may
be
oxidised
and
recycled
as
NAD
by
mitochondria.
respiration
Mitochondria

its
organelle
is
energy
the
on
is
the
harnessed
mitochondria.

is
structure
of
have
an
envelope
of
two
membranes
surrounding
a
protein-
a
rich
matrix.
They
are
too
small
to
see
properly
in
typical
school
or
college
mitochondrion
light

explain
how
the
structure
of
is
related
to
The
images
of
mitochondria
that
you
are
likely
to
see
a
are
mitochondrion
microscopes.
taken
with
electron
microscopes.
its
ribosome
matrix
crista
loop
of
DNA
inner
function.
mitochondrial
membrane
Link
outer
Mitochondria
including
and
have
other functions
replicating,
translating
their
mitochondrial
membrane
transcribing
DNA.
intermembrane
Chloroplasts
functions.
also
carry
Remind
out
yourself
endosymbiosis from Unit
in
Module
space
these
of
1.
See
2.4
Figure 2.3.2
1.
A longitudinal section of a mitochondrion showing location of important
processes. The functions of the different structures are shown in the table.
S tudy
Calculate
answer
foc us
the
actual
Summary
Almost
all
the
longitudinal
also
see
always
a
The
have
of
as
a
happens
The
NAD.
to
enzyme.
NAD
is
is
The
on
mitochondrion
that
one
are
in
shape.
They
branched.
during
is
stages
to
the
in
Figure
2.3.
1
so
you
can
the
NAD
inside
give
a
large
will
are
not
see
show
micrograph.
suggesting
After
site
that
always
replicating
of
the
include
and
of
you
electron
Y
ou
might
mitochondria
this
their
shape
DNA
and
have
they
cytokinesis.
matrix
both
that
this
circular
,
of
cristae
recycled
the
cells
oxidised
occurs
the
mitochondria
like
even
products
This
oxidation
of
of
1.
cylindrical
shapes,
mitochondrial
cycle.
Figure 2.3.1
images
sections
cross-sections
variety
divide,
length
question
reused
the
inner
surface
link
the
in
reaction
reduced
these
two
membrane,
to
take
these
and
Krebs
hydrogen
stages.
carrier
,
The
catalysed
enzymes
by
so
an
that
quickly.
A longitudinal section of a
Chemiosmosis
and
phosphorylation
mitochondrion (× 25 000)
This
is
very
similar
to
the
process
that
occurs
in
chloroplasts.
A
proton
Link
gradient
is
substrates.
Compare
the
structures
mitochondria
chloroplasts.
similarities
answer
with
Make
and
list
Reduced
of
of
differences
Summary
question
formed
the
using
Electrons
and
4.
then
NAD
on
the
mitochondria
membranes
through
24
up
energy
flow
from
along
an
the
oxidation
electron
of
respiratory
transport
chain.
in
those
a
set
for
to
into
is
oxidised
same
use
reach
the
side.
in
the
matrix
on
the
This
the
rest
of
cytosol.
in
the
matrix
means
the
Also
side
that
cell
has
NAD
opposite
of
A
TP
the
cristae
exported
to
from
direction.
pass
and
A
TP
is
from
through
glycolysis
two
has
to
pass
Module
Structure
outer
Composition
mitochondrial
membrane
phospholipid
Function
bilayer
and
proteins
permeable
to
pyruvate,
dioxide, ATP, ADP
inner
mitochondrial
folded
into
surface
cristae
membrane
to
give
a
–
phospholipid
large
complexes
area
chain
of
bilayer
with
electron
and ATP
protein
transport
pumping
space
lower
matrix
pH
than
synthetase
protein-rich
DNA
loop,
enzyme
DNA
loop
of
(similar
not
cytosol
region;
making ATP;
and
matrix
contains
ribosomes
and
many
ribosomes
ribosomes
and
within
those
in
you
–
smaller
than
endoplasmic
the
cytosol;
double-stranded
to
those
of
size
but
site
of
high
link
reaction;
with
DNA
of
the
or
glucose
Krebs
cycle;
of
protons
production
of
the mitochondrion; genes are transcribed
histone
as mRNA; rest of mitochondrial proteins
are coded for by DNA in the nucleus
and
proteins
translation
to form
–
assembly
of
amino
acids
proteins
as
Summary q uestions
foc us
imagine
the
would form
the
all
ions
concentration
cristae
pinching
off from
the
rest
of
the
inner
1
membrane
Explain
membrane-lined
sacs
like
thylakoids. Try
this
and
you
will
why
easy
to
mitochondria
see
directions
in
which
the
protons
are
pumped
and
move
down
gradient
is
the
are
light
use
the
calculation
on
result from
the
previous
same.
page
2
in
Take
and
a
a
your
piece
make
and
different
you
can
outline
you
cut
in
a
of
chloroplasts
Summarise,
and
6
the
Why
do
many
as
Make
shapes
then
draw
cristae
will
mitochondrion
carry
to
out
the
respiration.
compare
the
and functions
with
a
of
mitochondria.
a
simple
exchanges
between
a
sections.
and
the
as
the
aerobic
table
take
planes.
and
the
to
of
the
structures
occur
give
clay
of
sections
different
how
diagram,
model
Now
to
these
adapted
sizes,
5
a
of
made
in
Explain
Make
it
think
functions
4
modelling
drawings
you
appear
is
of
into
types
have
how
3
it
answer.
mitochondrion.
knife
Figure 2.3.3
a
their
your
electrochemical
under
see
microscope;
that
to
hydrogen
DNA codes for 13 of the proteins used in
not
they
permeable
not
prokaryotes);
reticulum
same
intermembrane
molecules
combined
rRNA
into
carbon
glucose
prokaryotes
S tudy
If
on
oxygen,
not
urea
proteins
70S
protons
but
space;
above,
intermembrane
1
that
mitochondrion
surrounding
cytosol.
mitochondria
divide?
Chemiosmosis in a mitochondrion
25
2.4
The
link
reaction
Pyruvate
Learning outcomes
is
and
an
energy-rich
mitochondrion
On
completion
should
be
able
of
this
section,
you
In
the
links
to:
matrix
state
that
oxidation
of
completed
in
dene
the
terms
of
Krebs
cycle.
pyr uvate
in
complex
The
the
that
into
matrix
mitochondrial
catalyses
components
dehydrogenase ,
the
carry
a
of
the
a
membranes.
reaction
this
out
of
that
complex,
following
to
pyruvate:
dehydrogenation
–
removal
of
a
hydrogen
atom
to
reduce
a
molecule
NAD
the
link
reaction
and
decarboxylation
–
removal
of
the
carboxyl
group
from
pyruvate
to
list
form
a
molecule
of
carbon
dioxide
products


as
proteins
enzyme
enters
dehydrogenation
describe
the
the
carrier
It
decarboxylation


to
known
molecule
of
and
large
compound.
mitochondria


is
a
cycle
pyruvate
each
is
through
is
glycolysis
which

Krebs
outline
the
Krebs
cycle,
state
transfer
of
the
(ethanoyl)
processes
that
occur
and
list
remaining
2-carbon
fragment
which
is
an
acetyl
the
group
to
coenzyme
A,
to
form
acetyl
coenzyme
A.
the
This
reaction
(actually
several
reactions)
is
called
the
link
reaction
as
it
products.
links
glycolysis
reaction
to
the
Krebs
cycle.
The
overall
equation
for
foc us
pyruvate
(3C)
+
coenzyme
A
+
NAD
reduced
→
+
coenzyme
The
link
2.
1.
1
on
reaction
page
is
shown
in
Figure
21.
link
is:
acetyl
S tudy
the
Remember
molecule
that
of
glycolysis
glucose.
The
produces
products
two
of
molecules
the
link
NAD
of
pyruvate
reaction
dioxide
from
each
are:
For each pyruvate molec ule
For each glucose molec ule
1
×
carbon
2
×
carbon
1
×
reduced
2
×
reduced
1
×
acetyl
2
×
acetyl
dioxide
carbon
+
A
dioxide
Link
Although
this
enzyme
decarboxylation
pyruvate
another
it
is
catalyses
not
decarboxylase
enzyme,
which
called
–
on
page
coenzyme A
you
can
read
One
a
(see
to
RuBP
page
performs
in
12).
A
is
a
enzymes;
of
the
catalyses
Link
role
coenzyme A
large
molecule
that
is
recognised
by
the
active
sites
of
34.
many
Oxaloacetate
NAD
that’s
Coenzyme
about
NAD
a
a
the Calvin
similar
cycle
four
of
cycle
research
There
are
that
nine
the
broken
cycle
are
the
compounds
Follow
the
the
other
into
Krebs
than
matrix.
and
to
A
other
is
known
it
as
who
compounds.
the
one
oxaloacetate,
Oxaloacetate
fragment;
cycle,
for
cycle
cycle
them
of
hydrogen
and
read
most
is
is
recycled
the
did
of
that
to
citric
much
is
the
by
acid
of
that
which
a
series
cycle
or
the
intermediate
Also,
convert
recycle
energy
the
pathways.
intermediates.
pathways
transfer
and
metabolic
cycle
using
the
reduced
Krebs
coenzyme
group
(1900–1981)
in
is
the
group
it.
substrates
to
Krebs
acetyl
acetyl
two -carbon
metabolic
in
cycle
the
acetyl
in
involved
rather
Krebs
present
this
a
the
reactions
down
substances
of
are
transfer
recognises
Hans
elucidate
compounds
are
for
form
Sir
to
between
compound
after
to
is
that
reaction
substance
reactions
Krebs
role
enzymes
the
carbon
acceptor
its
Some
them
to
oxaloacetate.
from
the
amino
acids
intermediates
in
other
The
main
role
intermediate
carriers.
these
descriptions
of
the
following
steps
carefully.
A
reaction
delivers
B
26
between
2C
acetyl
fragment
decarboxylation
coenzyme
(acetyl
(×2);
A
group)
removal
of
and
into
oxaloacetate
the
carbon
cycle
dioxide
to
(4C);
form
coenzyme
citrate
(6C)
A
Module
acetyl
1
Bioenergetics
coenzyme A
coenzyme A
reduced
4C
NAD
compound
(oxaloacetate)
A
C
NAD
E
6C
4C
compound
compound
NAD
4C
compound
C
B
reduced
CO
2
NAD
C
reduced
CO
2
5C
compound
P
FAD
NAD
ATP
4C
compound
C
D
FAD
reduced
NAD
ADP
Figure 2.4.1
Summary q uestions
The Krebs cycle. Follow the reactions of the Krebs cycle and nd brief
1
descriptions of each reaction, A
to
Outline what
in
2
C
dehydrogenation
substances,
and
the
(×4);
which
reduction
are
of
removal
oxidised
FAD
of
hydrogen
coupled
with
from
the
aerobic
substrate-linked
E
regeneration
pyruvate
reduction
of
NAD
What
are the
Krebs
cycle for?
3
A
TP
link
reaction
and
(×3)
(×1)
phosphorylation;
conditions.
intermediate
Using the
an
D
happens to
E
synthesis
link
reaction
as
example, distinguish
(×1)
between dehydrogenation
of
oxaloacetate
(4C
and
compound)
decarboxylation.
This
table
lists
the
processes
that
occur
and
the
products
formed
for
each
4
complete
‘turn’
of
the
cycle
and
for
each
molecule
of
glucose
that
Explain why
go through
completely
pyruvate
carrier
Process that occurs
Products
in the
of the
per one
‘turn’
Products
Krebs
cycle
Krebs
cycle
go through the
when
entering the
Make
a table to
molecule of
2
×
carbon
dioxide
4
×
carbon
3
×
reduced
1
×
reduced
1
× ATP
NAD
FAD
6
×
reduced
NAD
2
×
reduced
FAD
2
× ATP
6
cyclic
7
the
coenzyme
but
FAD
FAD
is
is
the
involved
in
prosthetic
the
Krebs
group
of
cycle.
the
NAD
is
linear
succinate
hydrogen
dehydrogenase
substrate,
dehydrogenase.
following
so
each
each
is
on
to
the
to
In
inside
enter
the
FAD
face
the
that
the
all
lysis
reaction
‘turns’ of the
six
the
site
to
NAD.
cristae
from
so
the
these
step
steps
in
glycolysis,
twice for
glucose
aerobically.
occur
that
is
it
Krebs
atoms from
a
are
in
molecules of
of
Explain why
carbon
respiration
succinate
not
stop
at the
Krebs
cycle.
Succinate
is
easy
for
its
8
matrix.
groups
molecules
that
S tudy
are
are
Suggest what
produced
foc us
Prosthetic
protein.
carbon
enzyme
dehydrogenation
not
S tudy
occurs
of
and
of
active
foc us
molecule
respired
transferred
malate,
S tudy
Remember
is
rather
pathways.
cycle, the
does
(4C),
having
pathways
After two
dioxide.
complex,
cycle.
similarities
advantages of
metabolic
glucose
coenzyme,
Krebs
include
as differences.
Explain the
than
phosphorylation
compare the
dioxide
as well
dehydrogenation
mitochondrion.
cycle with the
Remember to
that
rather
bilayer
glucose
Calvin
decarboxylation
lipid
per
5
mobile
proteins
oxidised.
than
Notice
molecules
is
organic
bound
to
a
Copy
21)
out
and
sheet
fates
of
of
in the
Krebs
the
link
reaction
pathway
with
(see
onto
paper. Annotate
the
cycle.
foc us
Krebs
diagram
happens to the ATP
a
page
large
your
information
about
the
products.
27
2.5
Oxidative
phosphorylation
The
Learning outcomes
link
reaction
removing
On
completion
should

be
able
describe
carriers
of
this
section,
you
are
all
reduced
recycled
hydrogen
Much
to
in
the
NAD
energy
those
is
the
carbon
hydrogen
coenzymes
to:
how
remove
and
atoms
atoms
and
still
produced
reactions
from
the
glucose
Krebs
as
cycle
carbon
intermediate
are
responsible
dioxide.
substances
They
as
the
for
also
reduced
FAD.
available
in
in
the
of
the
from
matrix
these
there
reduced
are
also
coenzymes.
some
from
In
addition
glycolysis.
mitochondria
An

explain
how
transport
generates
the
chain
a
electron
in
mitochondria
proton
enzyme
NAD
protein
gradient
explain
is
involved
ATP

how
in
by ATP
explain
the
the
proton
the
production
of
the
inside
NAD
The
can
electrons
complexes
protons
in
of
the
cristae
reused.
pass
the
the
of
be
The
from
electron
the
catalyses
reaction
enzyme
transport
the
oxidation
produces
to
compounds
chain.
The
of
reduced
protons
and
within
protons
join
the
a
matrix.
gradient
of
Each
synthetase
role
of
on
that
electrons.
pool

so
electron
there
oxygen
are
lost
linked
from
reduced
oxidation
and
NAD
passes
reduction
through
reactions
as
the
complexes
shown
and
here:
in
reduced
respiration.
reduced
carrier
NAD
A
reduced
carrier
NAD from
carrier
B
C
water
Krebs
S tudy
cycle
foc us
oxygen
You
can
refer
transport
it
is
a
to
chain
good
the
as
idea
the
to
ETC,
write
reduced
carrier
reduced
carrier A
B
carrier C
NAD
electron
although
out
the
reduced
name
in full rst
before
using
abbreviation.
Figure 2.5.1
In
to
these
the
the
and
cytosol.
the
FAD
whole
of
the
pump
protons
A
TP
table
the
summarises
molecules
oxidation
reduced
28
the
number
of
the
Reduced
inner
active
ATP
comes
in
for
Protons
foc us
reactions
energy
intermembrane
energy
except
The
oxidised
state
Linked oxidation and reduction reactions of the ETC
protons
The
S tudy
state
the
site
by
a
from
is
also
is
less
than
of
A
TP
at
their
Oxygen
is
the
protons
and
nal
but
pump
the
gives
its
it
so
available
of
the
accepts
The
a
the
do
the
pH
not
than
pass
made
matrix
in
the
along
which
of
matrix
the
available
impermeable
synthetase
gradient
and
and
a
as
to
protons,
molecules.
they
phosphate
do
so,
ion
to
the
form
reaction.
is
acceptor
.
catalysed
by
The
the
reaction
enzyme
produced
between
oxygen,
cytochrome
per
Process that occurs
ATP
in oxidative
molecule of
phosphorylation
coenzyme
glucose
reduced
ATP
oxidase.
produced
molecule of
produced following
of
reduced
NAD
and
to
NAD.
is
A
TP
from
transport
accumulation
lower
energy
from
ADP
protons
active
electrons
chain,
base
of
reactions.
concentration
electron
electrons
to
form
mitochondrion
synthetase
condensation
a
space
that
the
is
redox
transport
channel
down
of
these
This
oxidised,
membrane
the
transferred
intermembrane
electron
flow
is
space.
oxidation
of
reduced
NAD
2.5
10
oxidation
of
reduced
FAD
1.5
2
×
2.5
=
FAD.
×
1.5
=
3
25
per
Module
1
Did you know?
higher



H


H
H

H
H
H
concentration

H


Cyanide

H
of
H
is
an
irreversible
inhibitor
of
protons
H



H
H
H

cytochrome
H
nal
electron
chain
in
the
whole
We
cannot
membrane
proton
poisoning
oxidase.
It
inhibits
respiration,
of
aerobic
survive
respiration
transport
with
step
alone,
is
the
inhibiting
respiration.
on
so
so
anaerobic
cyanide
usually fatal.
pumps
S tudy
foc us
ATP

H
synthetase

Chemiosmosis
H
was
suggested
in

H
1961
by
Peter
ATP
electrons from
in
biological
independent
as
synthesis.
It
a
is
scientist
mechanism
now
for
accepted
as
oxidation
ADP
of
the
Mitchell

Pi
ATP
the
molecules
lower
respiration
in
way
in
which
bacteria,
ATP
is
synthesised
mitochondria
and

H
concentration
chloroplasts.
Remember
from

H
of
protons
Unit
Figure 2.5.2
Protons are moved across a membrane by proton pumps. This creates a
concentration gradient of protons that is a form of potential energy. Protons move down
1
that
probably
by
these
two
evolved
organelles
from
endosymbiosis
bacteria
(see
Unit
1,
the gradient through ATP synthetase.
Module
1,
2.4).
Evidence for
Summary q uestions
chemiosmosis
photosynthesis
1
Explain
2
State
what
oxidative
phosphorylation
roles
of
the following
in
oxidative
phosphorylation:
In
mitochondria,
chain;
proton
gradient; ATP
in
the
the
role
of
oxygen
in
Explain
how
the
structure
of
a
mitochondrion
makes
an
efcient
List
6
An
the
products
of
was
oxidative
carried
P,
Q
and
phosphorylation.
Isolated
in
a
addition
of
each
out
using
three
inhibitors
of
the
ETC
R. The
inhibitor
state
of four
electron
carriers,
A
to
D,
is
shown
in
the
solution
turn
into
Grana from
A
B
C
D
oxidised
reduced
reduced
oxidised
ATP
in
an
when
diffuse
oxidised
reduced
oxidised
reduced
of
reduced
reduced

oxidised
your
Make
table
a
respiration
the
medium
electron
carriers
in
this
electron
medium
transferred
the
energy
in
are
and
when
can
to
the
acid
make
an
dark.
medium
synthetase
transport
chain
to
make ATP.
membranes
made from
light-driven
pumps from
bacteria
and
and
synthetase from
answer.
mitochondria
7
of
thylakoids.
through ATP
Articial
ATP
explain
pH
protons
oxidised
protein
sequence
suspended
and
chloroplasts
acid
phospholipids,
the
as
the
the
solution
providing
State
the
alkaline
Protons from
R
in
carrier
alkaline
Q
than
table.
kept
P
the
after

Electron
in
lower
in
pumped
Inhibitor
is
chloroplasts
sucrose
removed from
the
pH
stroma.
solution
mitochondria,
the
spaces
illuminated
experiment
lower
process.

5
is
In
oxidative
the
phosphorylation
in
respiration.
thylakoid
4
spaces
matrix.
chloroplasts
Explain fully
pH
synthetase.
than
3
the
electron
intermembrane
transport
in
respiration:
is for.

the
and
showing
the
products
per molecule of glucose
of
each
of
the four
stages
of
aerobic
the
produce ATP
membranes
are
when
exposed
to
light.
29
2.6
Investigating
respiration
Respiration
Learning outcomes
requires
environment.
On
completion
should
be
able
of
this
section,
you
and
the
complex
to:
oxygen

state
may
that
be
the
rate
of
determined
a
rate
of
oxygen
explain
how
to
by
measuring
Respirometers

uptake
explain
how
to
are
They
up
and
use
exchange
dioxide.
green
and
Gas
parts
of
requires
between
involves
the
exchange
plants,
carbon
the
in
organism
absorption
plants
is
as
a
of
the
oxygen
more
photosynthesis
dioxide
and
raw
produces
material.
pieces
rely
on
of
apparatus
the
fact
that
designed
oxygen
to
is
measure
absorbed
rates
by
of
organisms
respiration
measure
use
a
and
carbon
dioxide
is
released.
T
wo
designs
of
a
rates
are
shown
here.
Y
ou
may
well
use
a
different
design,
but
all
of
respirometers
oxygen
the
gas
gases
uptake
set
to
in
by-product
respirometer
respirometer
carbon
of
respiration
during

exchange
animals,
of
because
as
respiration.
the
In
release
an
have

a
container

a
carbon
for

a
manometer
the
same
living
features:
organisms
control
dioxide
absorbent
respirometer.
to
measure
the
decrease
in
volume
of
air
inside
the
container
.
The
carbon
dioxide
absorbent
used
in
this
very
simple
respirometer
is
Link
soda
lime.
carbon
You
can
work
out
the
effects
and
dioxide
photosynthesis
exchange
questions
4
in
and
plants
5
on
in
form
calcium
is
calcium
carbonate.
hydroxide,
As
carbon
which
dioxide
reacts
is
with
absorbed
the
air
,
the
decrease
in
the
volume
of
oxygen
in
the
air
can
be
and
measured.
Summary
page
37
.
The
following
The
animals
is
bag
to
constituent
on
detected
gas
main
of
from
respiration
The
dipped
tubing.
of
coloured
soda
blowfly
water
lime
larvae
procedure
are
into
This
movement
a
weighed
beaker
fluid
of
is
the
is
of
and
when
placed
into
manometer
water
water
followed
in
with
the
a
dye
using
the
fluid
and
narrow
simple
syringe.
so
a
this
that
drop
capillary
a
of
The
respirometer
.
capillary
droplet
enters
detergent
to
tube
the
ease
the
tubing.
plunger
The
respirometer
syringe
the
meniscus
plastic
capillary
gauze
air
tubing
marking
again
A simple respirometer with
some insect larvae
and
the
after
the
a
knowing
the
the
so
droplet
on
length
of
bench.
The
decreases.
syringe
the
recorded.
diameter
the
air
position
known
are
on
of
causes
start
time
put
inside
which
the
is
volume
pressure
pressure,
tube
Figure 2.6.1
as
the
of
the
The
volume
it
capillary
is
less
in
than
towards
volume
tubing
and
then
travelled
oxygen
can
the
reduces
atmospheric
Measurements
distance
of
moves
reduction
move.
capillary
time.
The
that
to
droplet
The
be
are
taken
marking
by
the
by
it
droplet
calculated
tubing.
Precautions:
S tudy
1
foc us
Soda
lime
touch
Look
table
carefully
and
question
at
answer
the
results
in
this
2
Do
Summary
2.
up
3
not
the
Leave
and
them
or
handle
air
in
the
other
let
the
the
carbon
them
dioxide
come
into
respirometer
syringe
respirometer
or
so
alter
that
absorbents
contact
once
the
the
it
is
set
of
harmful;
the
up;
behaviour
rate
are
with
of
do
not
organisms.
handling
the
movement
may
heat
animal.
becomes
constant.
Temperature/°C
Movement of
4
Return
the
droplet
to
the
end
of
the
tube
by
pushing
in
the
syringe
droplet due
plunger
.
to oxygen
5
Do
not
leave
the
animal
in
the
syringe
for
too
long
without
removing
uptake/mm
the
10
8
At
plunger
least
three
absorbed
20
the
results
be
movement
air
the
should
air
.
be
taken
so
a
mean
volume
of
oxygen
calculated.
heats
up
of
the
and
droplet
expands
could
in
the
be
due
syringe
to
a
change
then
in
temperature.
this
will
cause
cools
and
contracts
If
the
34
droplet
the
30
refresh
16
The
30
can
to
to
move
droplet
will
away
move
from
the
towards
syringe
the
and
syringe
if
it
(precaution
2).
then
Module
A
control
respirometer
material
of
suitable.
If
needs
to
the
there
be
Barcroft
manometer
This
tube
is
taken
experimental
The
same
any
account
to
up
of
exactly
before
shown
counter
therefore
of
when
the
the
the
droplet
calculating
below
vessel
same
animals.
calculating
has
movements
compensating
and
in
replaces
movement
respirometer
a
temperature
set
respirometer
tube
is
is
volume
or
pressure
due
in
this
of
affect
tube
changes
both
of
in
Link
this
the
uptake.
to
Another
design
replaces
the
each
between
other
the
out.
menisci
Readings
on
each
are
side
taken
of
the
by
measuring
of
respirometer
syringe
tube
which
can
be
bath
(see Question
with
put
7
a
in
on
a
boiling
water
page
39).
the
temperature.
Any
changes
equally
of
and
S tudy
cancel
Bioenergetics
are
then
attached
in
sides
inert
beads
fluid
oxygen
control
to
some
glass
control,
thermobarometer
.
will
but
movement
rates
a
way
Small
1
the
foc us
distance
U-tube.
Textbooks
show
this
(Figure
calibrated
and
exam
type
of
sure
work,
how
analyse
you
to
the
often
respirometer
2.6.2). They
make
papers
are
tricky
understand
use
them
to
use;
how
and
they
how
to
results.
syringe
rubber
tube
S tudy
Rates
screw
screw
clip A
clip
of
foc us
oxygen
uptake
are
often
B
expressed
as
volume
of
oxygen
3
water
bath
of
gram
desired
This
temperature
of
of
tissue
involves
the
per
hour
some
(mm
careful
per
–1
g
–1
h
).
analysis
results.
respirometer
respirometer
chamber A
chamber
B
Summary questions
glass
beads
actively
respiring
1
Dene
the
terms
gas exchange,
organisms,
respirometer,
e.g.
insect
2
larvae
soda-lime
Explain
the
results
U-shaped
manometer
the
tube
soda-lime
2
containing
coloured
3
Barcroft respirometer set up to measure the rate of respiration of
Plan
an
how
the
rate
germinating seeds (tube B). Boiled seeds of the same mass are in tube A
of
seeds.
your
The
advantages
into
a
of
this
respirometer
is
that
the
tubes
can
also
be
water
bath
to
maintain
a
constant
temperature,
although
investigation
water
bath
fluctuations
in
temperature
are
compensated
for
even
The
a
by
respiration
Include
plan:
a
addition
of
the
absorbed
syringe
can
be
means
taken
by
that
measurements
depressing
the
of
syringe
the
menisci
to
their
original
position.
A
problem
with
the
germinating
the following
prediction;
a
in
method
set
of
numbered
points;
the
an
results
explanation
will
be
of
collected
volume
plunger
this
how
rates
of
respiration
will
to
be
the
in
out
affects
tube
and
return
on
out
how
oxygen
to nd
temperature
precautions;
of
table
inserted
as
B.
the
page.
to
2
Figure 2.6.2
opposite
liquid
absorb CO
a
in
to
absorb CO
of
germination.
is
calculated
and
presented
on
a
that
graph.
the
scales
on
syringes
are
often
difcult
to
read
and
reading
errors
can
be
introduced.
4
Explain
why
respiration
Germination
is
the
process
that
occurs
when
the
embryo
inside
a
dry
to
grow,
seeds.
cells
to
often
When
following
they
absorb
a
period
water
of
this
dormancy.
activates
Most
plants
enzymes
and
the
respiration
most
active
mitochondria
active.
stage
in
Enzymes
substrates
are
the
very
in
dry
the
and
life
seeds;
hydrolyse
glucose
high
germinating
cycle
when
starch
fatty
in
of
a
the
and/or
plant.
seeds
lipids
seeds.
There
are
to
Germination
are
enzymes
soaked,
give
the
both
changes
release
causes
5
swell.
of
of
seeds
germination.
Rates
of
respiration
seeds
increase
removed.
Rates
rate
pea
seed
during
starts
the
of
their
Suggest
pea
testas
why
this
are
is
so.
is
and
become
respiratory
if
in
6
Suggest the
simple
limitations of the
respirometer
Barcroft
and the
respirometer
shown
here.
acids.
31
2.7
Anaerobic
respiration
This
Learning outcomes
section
going
On
completion
of
this
section,
be
able
concentrate
state
that
some
mammals
can
tissues
the
survive
the
in
time
respiration for
lengths
time
lactate
the
is
reaction
in
which
But
there
in
mammals,
although
we
are
humans.
an
athlete
for
of

explain
the
role
this

explain
the
concepts
to
the
for
run
athlete’s
as
the
100
metres,
aerobic
there
muscles.
well
as
respiration
will
not
Muscle
tissue
needed
under
to
be
these
provide
conditions
aerobically.
is
responds
quickly
cannot
insufcient
to
to
not
be
the
demand
supplied
oxygen,
does
carriers
be
the
take
to
nal
reaction
place.
oxidised,
so
for
extra
energy
mitochondria
There
the
of
is
in
the
enough.
form
of
As
oxidative
no
Krebs
fast
way
cycle
for
and
the
the
reduced
link
reaction
reaction
stop
of
for
lack
of
NAD
and
FAD.
oxygen
This
oxygen
absorbed
phosphorylation
produced
and
takes
oxygen
hydrogen
decit
respiration
short
A
TP
.
describe
on
anaerobically
Glycolysis

it
oxygen
energy
respires
using
anaerobic
of
anaerobic
to:
sufcient

about
mammals
you
In
should
to
is
in
also
means
that
the
mitochondria
are
unable
to
recycle
the
reduced
debt.
NAD
from
catalyses
the
temporary
in
the
As
glycolysis.
reduction
hydrogen
muscle
glycolysis
way
to
cells

and
NAD
triose
of
then
large
so
the
pyruvate
acceptor
produces
recycle
2
Fortunately,
that
phosphate
to
to
form
diffuse
enzyme
form
quantities
glycolysis
lactate.
lactate,
into
of
lactate
the
Pyruvate
which
starts
acts
to
as
a
accumulate
blood.
pyruvate
can
dehydrogenase
there
must
be
some
continue.
(3C)
4ADP
Figure 2.7.1
Some athletes train to
2H
4ATP
2

improve the way in which their body
NAD
performs when they make huge demands
on the anaerobic respiration in their
2
muscles

reduced
NAD
S tudy
foc us
2
A
common
describe
there
The
is
question
the fate
no
word
of
oxygen
‘fate’
on
this
topic
pyruvate
in
may
muscle
seem
is:
Figure 2.7.2


when
tissue.
odd.
The
overall
equation
for
under
these
happens
to
anaerobic
respiration
in
muscle
tissue
is:
It
H
6
what
(3C)
The pathway that produces lactate in mammalian muscle tissue
C
means
lactate
O
12
→
CH
6
CH(OH)COOH
3
pyruvate
conditions.
with
a
Oxygen
net
gain
of
demand
2
A
TP
.
exercise
exercise
Oxygen
during
exercise
ends
and
deficit
heart
increased
2.5
occurs
time
demand for
debt
is
because
to
repaid
adjust
the
to
lungs
the
oxygen
during
the
recovery
2.0
1
period
is
1.5
used
through
to
extra
reload
myoglobin, to
md
3
negyxO
nim
/ekatpu
Oxygen
take
metabolic
uptake
haemoglobin
oxidise
organs operating
1.0
oxygen
at
lactate
higher
that
and
and
than
to
keep
normal
rate
0.5
Oxygen
Figure 2.7.3
Exercise physiologists
uptake
0
2
4
6
8
10
12
14
16
18
20
22
24
monitor the performance of athletes
at
rest
time/mins
during their training by measuring
breathing, heart rate, blood pressure,
Figure 2.7.4
blood composition and other parameters
exercise
32
The oxygen consumption by an athlete before, during and after strenuous
Module
Anaerobic
as
A
TP
However
,
reduces
slow
respiration
very
quickly
the
the
down
build
a
increase
or
stop.
supply
The
race
in
of
of
of
is
to
lactate
in
an
the
useful
since
it
provides
energy
muscle
tissue
us
lowers
feel
athletes
tired.
are
able
the
pH
This
to
and
means
tolerate
we
higher
blood.
increase
in
aerobic
is
is
making
training,
supply
how
in
their
difference
shows
tissue
Bioenergetics
exercise.
enzymes,
lactate
there
This
muscle
support
Through
oxygen
A
TP
.
graph
up
efciency
concentrations
During
in
to
1
demand
known
oxygen
for
respiration
as
the
energy,
at
the
oxygen
consumption
but
rate
not
an
required
to
decit
changes
during
and
after
exercise.
Figure 2.7.5
After
exercise
oxygen
is
during
required

aerobic

the
recovery
period,
oxygen
uptake
remains
high
as
Anaerobic respiration
provides energy quickly so that predators
can sprint to catch their prey
for:
respiration
of
lactate
in
the
liver
re- oxygenating
haemoglobin
in
the
blood

re- oxygenating
myoglobin,

resynthesis
Link
of
A
TP
and
which
creatine
is
a
store
of
phosphate
oxygen
in
in
muscle
muscle
tissue
Creatine
tissue
phosphate
available

supporting
high
rates
of
respiration
in
all
organs
after
transferred
high
Oxygen debt
is
the
end
why
of
the
people
strenuous
race
the
athlete
to
will
breathe
have
deeply
built
after
up
an
taking
oxygen
a
is
a
readily
phosphate
short
debt .
burst
to ADP
demand for
tissue.
continue
of
that
can
exercise.
be
At
store
It
is
not
a
when
energy
very
in
there
is
a
muscle
large
store.
This
of
exercise.
Link
Lactate
into
dehydrogenase
pyruvate.
This
catalyses
happens
in
the
the
reaction
liver
.
in
Some
which
of
the
lactate
is
pyruvate
converted
is
Most
converted
to
glucose
by
the
reverse
of
the
reactions
of
glycolysis.
intracellular
reversible;
requires
energy,
which
is
provided
by
the
oxidation
of
pyruvate
reactions
are
This
the
enzymes
catalyse
in
forward
and
back
reactions. The
mitochondria.
direction
If
to
the
be
athlete
supported
started
at
a
supported
long
The
fast
by
by
the
glucose,
table
taking
by
part
aerobic
speed
aerobic
endurance
fuelled
little
is
the
will
such
as
a
athlete
have
to
of
fat
the
and
event,
means
slow
Glycogen
‘hits
advantages
This
marathon
respiration
the
endurance
respiration.
he/she
event,
shows
an
respiration.
aerobic
then
in
and
in
the
that
down
to
muscles
run.
if
a
is
and
disadvantages
to
of
the
the
If
has
determined
athlete
speed
glucose.
has
exercise
used
However
,
some
wall’
then
that
up
reaction
the
and
takes
is
concentration
of
product(s).
is
muscles
is
a
by
substrate(s)
during
there
that
a
are
very
stop.
anaerobic
Summary q uestions
respiration.
1
Advantages
Why
to
Disadvantages
do
be
endurance
supported
by
events
have
aerobic
respiration?
‘buys
time’
at
the
beginning
of
wastage
of
energy;
glucose
is
2
exercise
until
the
lungs,
heart
and
converted
to
lactate,
which
Dene
the
terms
respiration,
blood
can
provide
oxygen
to
muscle
energy
anaerobic
is
oxygen decit,
oxygen
rich
debt
tissue
3
provides
a
lot
of ATP
very
quickly
lactate
is
toxic
above
a
certain
the
concentration
provides ATP for
explosive
that
short-term
activity,
lasts for
only
such
as
a few
sprinting,
seconds
net
gain
of ATP
molecule
of
Describe
the fate
absence
of
of
pyruvate
oxygen
in
in
muscle
tissue.
is
only
glucose
2
per
4
Explain
in
the
what
happens
body following
strenuous
to
the
lactate
end
of
exercise.
33
2.8
Anaerobic
respiration
Y
east
Learning outcomes
in
On
completion
of
this
section,
is
fact
be
able
many
state
in
that
yeast
are
anaerobic
produces
respiration
carbon
dioxide
Like

of
that
grows
on
the
surface
of
fruit.
There
are
yeast.
found
in
rotting
fruit
microorganisms
where
The
decarboxylated
As
pathway
to
you
form
can
is
not
they
the
ethanal.
see
from
can
the
oxygen
same
Ethanal
the
respire
concentration
as
is
in
animals.
then
metabolic
anaerobically
well
Pyruvate
reduced
pathway
as
is
to
this
as
is
become
recycles
NAD.
ethanol
describe
carbon
the
reaction
dioxide
and
in
which
ethanol
2
describe

triose
phosphate
(3C)
are
produced

often
many
aerobically.
ethanol.
and
types
fungus
to:
low.

unicellular
yeast
you
Y
easts
should
a
in
4ADP
the
commercial
uses
of
2H
4ATP
2

yeast.
NAD
2

2
Candida
on
and
is
a
type
inside
reduced
NAD
Did you know?
of
yeast
humans
that
and
is

2

ethanal
(2C)

ethanol
(2C)
lives
the
2CO
cause
of
oral
and
vaginal
2
thrush.
Figure 2.8.1
The
S tudy
The pathway that produces ethanol in yeast
overall
equation
for
anaerobic
C
H
6
Pyruvate
decarboxylase
is
in
yeast
is:
enzyme
that
in
(see
breaks
down
a
net
→
2C
6
H
2
OH
+
2CO
5
gain
of
2
2
A
TP
.
pyruvate
These
page
O
12
the
with
yeast
respiration
foc us
reactions
are
not
reversible.
Y
east
cannot
respire
ethanol.
26).
Fermentation
Did you know?
The
term
applied
Ascorbic
acid
(vitamin C)
is
added
to
make
the
protein
gluten
anaerobic
it
has
the
more
time for
elastic,
so
in
in
two
distinct
yeast
and
ways.
other
It
used
to
be
microorganisms.
come
to
be
applied
to
the
culture
of
any
More
microorganism
cell
grown
in
either
anaerobic
or
aerobic
The
ability
used
in
bread

brewing

wine
The
is
of
yeast
bread
acid
flour
and
left
There
in
dough
with
then
yeast
ferment
sugar
to
form
ethanol
and
carbon
dioxide
ways:
making
ascorbic
sugar
.
to
main
making.
mixed
and
yeast
making
role
causes
of
three

Bread
in
is
respires
a
bread
to
(made
water
to
humid
some
making
rise
–
a
is
to
process
from
wheat,
make
anaerobically.
at
dissolved
The
rye
dough.
atmosphere
oxygen
produce
carbon
sometimes
The
maize),
dough
35 °C
in
carbon
or
the
for
the
which
leavening.
sugar
is
dough
dioxide
dioxide,
called
folded
yeast
but
if
released
Y
east
(sucrose),
and
to
respire
this
is
forms
salt,
kneaded
the
used
of
up,
pockets
The baker is kneading the
dough, which mixes in some air to provide
oxygen for the yeast. Oxygen does not
of
gas
in
ethanol
the
dough
produced
is
causing
burnt
it
off
to
rise.
and
The
goes
up
dough
the
is
then
baker ’s
baked
and
any
chimney.
diffuse through the dough so respiration
becomes anaerobic during the time the
dough is left to prove before it is baked.
34
or
conditions.
reducing
leavening.
is
Figure 2.8.2
used
in
eukaryotic
the flour
is
respiration
to
recently
dough
‘fermentation’
to
During
sucrose
the
to
fermentation,
the
monosaccharides
yeasts
and
convert
respire
maltose
them
in
the
flour
anaerobically.
and
Module
Brewing
Cereal
grains,
usually
barley,
are
the
main
raw
material
for
brewing.
The
Endosperm
in
the
individual
grains
is
rich
in
starch.
Y
east
cannot
so
the
grains
are
soaked
and
allowed
to
germinate.
The
mixed
with
yeast
to
ferment
and
produce
sugar
ethanol
dioxide,
both
of
which
are
required.
The
stages
are
Malting:
The
grains
produce
amylase
to
catalyse
the
grains
to
stopped
70 °C
maltose.
by
to
denature

Milling:

Mashing:
Y
east
heating
The
the
the
grains
can
respire
grain
to
enzymes
are
a
maltose.
and
crushed
The
temperature
outlined
hydrolysis
to
stop
help
the
germination
between
and
other
water
soluble
is
poured
compounds
over
to
the
40 °C
Boiling:
The
wort
is
boiled
with
concentrates
the
wort,
remove
grain
the
to
‘wort’.
hops,
which
is
Fermentation:
and
top
S.
carbon
fermenters
pastorianus
called
18 °C
When
ready
S.
that
(ales)
be
is
added
Y
easts
produce
are
used
bottled,
is
to
of
produce
then
ferment
the
type
ales.
dissolve
provide
for
the
or
the
( S.
the
put
wort
the
foc us
sugars
flavour
.
to
why
yeast
can
respire
The
produce
but
not
starch. You
pastorianus
10 °C
of
the
used
your
need
knowledge from Unit
to
1.
ethanol
cerevisiae
fermenters
between
mixture
into
to
(lagers)
are
type
be
Temp.
Movement of droplet
/°C
/mm
and
is
ltered.
The
beer
is
then
1
2
3
casks.
5
6
6
5
10
8
8
7
15
13
12
11
20
16
18
12
30
28
32
26
35
14
12
13
making
such
as
grapes
provide
crushed
to
extract
ferment
at
temperatures
known
as
the
skins
and
Wine
makers
‘must’;
then
productions
the
put
used
the
contaminants.
ferment
grape
to
is
Y
easts
is
wild
to
extracted
added
from
and
S.
to
of
a
the
press
wild
but
the
to
and
left
are
to
fermented
remove
aged
in
yeasts
cerevisiae
Grapes
juice
The
heated,
yeast,
the
making.
30 °C.
ltered,
kill
strain
wine
through
vats,
strains
treated
the
is
for
20 °C
passed
settling
of
sugar
Y
east
between
use
fruit
sugars
juice.
this
into
the
the
and
pulp
is
fruit
bottled.
commercial
and
any
ellipsoideus
other
are
added
to
fruits.
Summary q uestions
1
Make
a
table
between
to
show
anaerobic
the
similarities
respiration
in
and
differences
mammals
and
5 °C,
put
capillary
mixture
Name
the
monosaccharides
that
are
produced
hydrolysing
a
maltose,
and
b
a
tube
the
of
Explain
yeast
the
in
biological
bread
principles
making,
wine
Dough
with
added
yeast
involved
making
expands
and
in
diameter
using
yeast
place.
Plan
an
as
investigation
it
is
left
in
of
the
dough
is
directly
recorded. The
and
glucose
kept
a
at
the
droplet
same
along
temperature
was
increased
the
of
to
the
of
the
droplet
10 °C
recorded. Other
to
see
of
were
the
used
as
capillary
shown
tubing
in
was
the
table. The
4 mm.
if
the
students
results
are
in
the
table
above.
a
rate
Process
proportional
to
the
results
and
draw
a
table
to
show
the
of
mean
expansion
of
brewing.
a
warm
was
and
sucrose.
The
4
movement
movement
temperatures
3
respirometer
by
and
yeast
into
temperature. The
in
yeast.
2
rate
of fermentation
at
each
temperature
the
investigated.
temperature
of
proving.
b
5
A
student
the
rate
investigated
the
of fermentation
in
effect
yeast.
of
temperature
10 g
of
yeast
i
Draw
a
explain
on
graph
the
fermentation
was
of
effect
of
the
of
results,
and
temperature
ii
describe
on
the
and
rate
of
yeast.
3
mixed
with
100 cm
of
a
10%
glucose
solution
3
is
fermentation.
complete
canned
beers.
Module
1.
cooled.
bottom
T
emperatures
grains
in
sugars.
Saccharomyces
The
lager-type
carlsbergensis .)
fermentation
to
Wine
Fruits
Y
east
dioxide.
1.5
and
use

See
hydrolysis.
form
which
bread flour.
maize
of
maltose
boiling
of
cornflour.
Explain

of
of
below.
S tudy
Hot
provides
endosperm
of Unit
starch
store
and
forms

energy
endosperm
is
The
carbon
the
seeds. The
wheat
and
is
respire
some
extracted
Bioenergetics
Link
endosperm
starch,
1
at
c
State
a
limitation
of
the
method.
35
2.9
Respiration:
summary
Organisms
Learning outcomes
compares
On
completion
should
be
able
of
this
section,
you
state
the
be
classied
different
hydrogen
types
of
according
similarities
respiration
how
in
they
terms
of
respire.
the
The
nal
table
electron/
acceptor
.
electron/
Product
Type of
Examples
and
hydrogen
differences
to
to:
Final

can
between
aerobic
respiration
and
Prokaryote
Eukaryote
aerobic,
Escherichia
humans;
involving
coli
yeast
none
acceptor

anaerobic
respiration
derive
yield
the
aerobic
of ATP
respiration
of
in
oxygen
the
water
glucose
oxygen

compare
aerobic
the
and
energy
yields
anaerobic
of
respiration
nitrate
(NO
)
dinitrogen
anaerobic,
Pseudomonas
(N
denitrication
denitricans
hydrogen
anaerobic,
Desulfovibrio
sulphide
sulfate
vulgaris
(H
reduction
3
of
glucose.
)
2
sulphate
(SO
)
none
4
S)
2
3+
ferric
iron
(Fe
)
ferrous
iron
anaerobic,
Shewanella
iron
putrefaciens
none
2+
(Fe
The
Did you know?
advantage
electron
Oxygen
They
Earth
is
toxic
evolved
were
survive
muds,
in
to
which
such
occur
prokaryotes.
conditions
anaerobic
places
mangrove
some
when
in
and
as
on
they
wide
and
in
acceptors
range
of
before
roles
recycling
able
is
the
oxygen
to
that
than
of
other
methods
oxygen.
are
among
the
nal
organisms
oxygen
entered
mineral
reduction
use
the
absence
other
survival
evolved
in
being
chain
material
electron
anaerobic
wetlands
organic
of
transfer
)
electron
can
The
prokaryotes,
elements,
such
as
able
There
some
Some
of
have
nitrogen
and
for
the
respiring
organisms
prokaryotes.
atmosphere.
acceptors
continue
is
to
a
use
very
which
important
sulphur
.
swamps.
Organisms
are
that
obligate
can
survive
aerobes.
Those
only
that
with
oxygen
cannot
are
survive
obligate
with
aerobes .
oxygen
are
We
obligate
anaerobes
Some
organisms,
anaerobically.
The
table
such
These
shows
Feature
the
as
are
yeasts,
can
facultative
differences
Type of
respire
both
aerobically
and
anaerobes
between
aerobic
and
anaerobic
respiration.
respiration
Aerobic
Anaerobic
Yeast
Mammal
yes
no
Link
You
can
page
47
.
read
about
denitrication
decarboxylation
yes
oxidation
yes
on
reduced
of
NAD
products
per
–
in
yes
in
cytosol
mitochondria
using
using
electron
H
ETC
6
×
6
× CO
O
ethanal
2
×
2
× CO
by
as
acceptor
ethanol
yes
in
using
electron
2
×
of
2
glucose
net
*
36
gain
See
the
2 ATP
2
2 ATP
of ATP
table
30*
opposite.
2
2
as
acceptor
lactate
2
molecule
cytosol
pyruvate
Module
1
Bioenergetics
Yield of ATP
The
15
yield
times
difcult
glucose
which
of
A
TP
greater
to
from
than
estimate
molecule
does
not
intermediates
is
aerobic
that
since
for
the
gure
completely
necessarily
in
respiration
anaerobic
the
Krebs
for
broken
happen.
cycle
shown
aerobic
down
Y
ou
may
is
in
respiration.
will
enter
the
This
table
respiration
to
water
and
remember
other
as
about
difference
assumes
carbon
from
metabolic
is
that
a
dioxide,
page
26
that
pathways
and
S tudy
are
not
respired
hydrogen
and
completely.
oxygen
atoms
This
in
means
glucose
that
some
remain
in
of
the
energy-rich
compounds.
The
This
tends
to
reduce
the
total
yield
from
different
table
with
the
shows
how
metabolic
to
calculate
pathways
in
total
yields.
sections
methods
by
which
glucose.
reduced
The
foc us
carbon,
2.2
Y
ou
and
need
2.4
to
and
check
the
back
lists
the
NAD from
mitochondria
glycolysis
are
enter
beyond
the
of
scope
of
this
book.
products.
Stage of
Input of ATP
Direct yield of ATP
Indirect yield
aerobic
(phosphorylation
(substrate-level
of ATP via
respiration
of
phosphorylation)
reduced
hexose)
and
NAD
reduced
Summary q uestions
FAD
1
glycolysis
–2
4
3
or 5 (NAD)*
0
5
(NAD)
does
the
‘net
yield’
of ATP
mean?
2
link
What
Explain
would
why
not
an
be
obligate
of
any
aerobe
use
in
bread
reaction
making.
Krebs
cycle
2
15
(NAD)
3
3
Make
a
and
mitochondrion
a
show
Totals
–2
6
drawing
26
the
cytosol
gives
a
theoretical
maximum
yield
of
32
–
2
=
30
molecules
of
32
depending
enter
on
the
how
the
hydrogens
mitochondria
–
from
there
are
reduced
two
NAD
methods
of
rise
either
reduced
to
NAD
three
from
or
to
five
molecules
of
ATP
for
the
of
a
this,
maximum
two
of
A
TP
4
(32
or
30)
is
rarely,
if
ever
,
that
with
occur
palisade
the
daylight
mesophyll
hours. What
a
to
these
plant
is
exchanges
in
darkness?
molecules
glycolysis ).
number
and
which
Explain
why
respiration
This
and
from
for
when
give
exchanges
them
during
happens
glycolysis
chloroplast
A
TP
cell
(or
a
or 28*
between
This
of
(FAD)
the
and
processes
of
photosynthesis
achieved
are
not
opposites
of
each
other.
because:
5

some
intermediates
in
the
metabolism
of
glucose
are
converted
Plants
their
other
substances
rather
than
being
broken
down
completely
(see
on
page
the
proton
happens
gradient
is
used
to
power
the
movement
of
substances
matrix,
e.g.
pyruvate
and
phosphate
chemiosmosis
is
not
efcient,
as
some
mitochondrial
membrane
into
protons
the
‘leak’
through
but
and
important
the
the
none
of
point
difference
to
remember
between
net
yield
the
energy
oxidative
uptake
and
in
the
anaerobic
transfer
respiration
occur
net
here
yield
of
anaerobic
the
aerobic
which
the
and
a
carbon
plant
during
a
and
hours). You
may
day
wish
to
cytosol.
not
in
respiration,
reactions
in
is
oxygen
between
the
draw
The
of
environment
(24
outer
the
ions
its

to
into
dioxide
the
with
Describe
26)
release

gases
environment.
Krebs
what
cycle
exchange
into
link
calculation
respiration
is
2.
This
reaction,
is
in
the
table,
(about
30)
because
Krebs
cycle
and
two
graphs
exchanges
the
carbon
your
patterns
show
one for
other for
Annotate
the
–
to
oxygen
and
dioxide.
graphs
you
the
have
to
explain
drawn.
respiration.
37
2.
10
Practice
exam-style
questions:
Respiration
Answers to
1
The
all
exam-style questions
diagram
respiration
represents
in
a
a
can
metabolic
be found on the
pathway
accompanying CD.
in
ii
State
mammal.
two
the
precise
types
of
sites
in
a
plant
phosphorylation
cell
of
shown
the
in
the
diagram.
CH
CH
OH
[2]
OP
2
2
iii
O
O
Give THREE
between
similarities
and THREE
photophosphorylation
differences
and
oxidative
phosphorylation.
ATP
ADP
[6]
2
1
iv
POH
CH
C
OP
POH
2
2
CH
C
OH
v
2
2
O
List THREE
plant
cell.
State
FIVE
compounds
that
are
oxidised
in
a
[3]
uses
of ATP
in
a
plant
cell.
[5]
O
3
a
Outline
the
processes
which
occur
in
respiration
3
during:
ADP
ATP
i
glycolysis,
ii
the
link
iii
the
Krebs
[5]
reaction,
and
[3]
Pi
O
O
CH
cycle.
[4]
X
OH
2
b
CH
CH
OH
enables
OP
CH
NAD
2
CH
Describe
how
the
structure
of
a
mitochondrion
OH
aerobic
respiration
to
occur
efciently.
reduced
CH
OP
OP
2
2
You
may
use
a
labelled
and
annotated
diagram
to
NAD
4
ADP
help
Y
c
your
There
are
Suggest
O
O
answer.
no
[2]
mitochondria
how
they
in
red
blood
cells.
respire.
[1]
ATP
O
O
CH
C
OH
OH
C
OH
S tudy
C
CH
CH
CH
3
ATP
CH
ADP
H
2
OH
You
OH
CH
O
foc us
OH
OP
could
use
a
table
to
plan
your
answer
to
question
3a.
2
2
CH
OP
2
6
a
5
i
Name
molecules
2,
3,
4
and
6.
[4]
4
a
Describe
the formation
mesophyll
ii
State
where
substance
1
comes from.
iii
State
what
happens
at
stage
iv
State
what
happens
to
the
during
of ATP
the
in
a
daylight
palisade
hours.
[5]
[1]
b
Y.
reduced
cell
Discuss
the
importance
of ATP
in
plant
cells.
[5]
[1]
NAD.
[2]
5
NAD
and
coenzyme A
are
coenzymes
involved
in
respiration.
b
i
Discuss
the
importance
of
the
reaction
that
The
occurs
at
X.
concentration
[2]
ii
State
and
the fates
anaerobic
of
molecule
conditions
in
6
a
under
aerobic
mammal.
a
[4]
a
Explain
why ATP
is
a
nucleotide.
0.8 µmol g
Explain
The
diagram
palisade
shows
NAD
in
muscle
is very
limited,
tissue.
reduced
NAD
is formed
during
Explain
[2]
how
reduced
NAD
is
recycled
in
muscle
[3]
tissue
b
how
of
respiration.
b
2
of
–1
about
the formation
of ATP
in
a
i
oxygen
when
is
not
oxygen
is
available,
and
ii
when
available.
[4]
cell.
c
Discuss
the
a
Describe
role
of
coenzyme A
in
respiration.
[2]
oxidative
ADP+P
photophosphorylation
6
what
happens
to
pyruvate
in
a
phosphorylation
muscle
energy from
the
energy from
cell
and
in
yeast
cells
under
anaerobic
light
conditions.
oxidation
[5]
of
b
Explain
the
importance
of
the
reactions
you
compounds
describe.
[4]
ATP
c
i
38
Explain
the
term
phosphorylation.
[2]
Explain
use
of
the
biological
yeast
in
principles
making
bread,
involved
wine
and
in
the
beer.
[6]
Module
7
The
the
apparatus
rates
leaves
of
of
in
Figure
respiration
pinto
2.
10.
1
of
was
used
germinating
to
compare
seeds
8
and
During
strenuous
running,
beans.
muscles
fat. Glycogen
can
anaerobically,
a
Name
a
why
is
suitable
chemical
to
use
as
X
and
used.
apparatus
with
the
closed
clip
and
time. The
was
put
into
open. After
the
position
results
Describe
are
a
10
of
water
bath
minutes
the
the
droplet
at
0
the
is
changes
clip
was
recorded
over
10
Explain
the
Explain
why
20
25
30
of
as fast
changes
a
long-distance
of
both
only
that
glycogen
and
aerobically
respired
occur
why
as
a
a
tissue
and
aerobically.
in
the
during
supply
of
the rst few
exercise.
that
person
strenuous
Explain
35
muscle
strenuous
c
end
15
of
b
as follows.
5
within
minutes
27 °C
d
Time/
respired
whilst fat
as
stores
[3]
energy
The
be
such
their
Bioenergetics
explain
a
it
exercise,
use
1
you
[4]
have
breathes
described.
deeply
at
[4]
the
exercise.
marathon
[5]
runner
does
not
run
sprinter.
[3]
minutes
9
Position of
0
0
0
31
65
95
130
An
investigation
production
162
of
droplet/
mitochondria
ADP,
mm
The
phosphate
Explain
i
why
a
water
bath
is
used,
why
the
apparatus
is
left for
10
closing
the
Explain
clip.
The
the
diameter
results
in
of
the
the
capillary
table
to
the
was
prepared. To
and
excess
of
this
pyruvate
these four
suspension
was
and
added
oxygen.
substances
were
intervals.
why
than
pyruvate
was
used
as
the
substrate
glucose.
[1]
[1]
b
c
into
minutes
rather
before
out
mitochondria. A
and
a
ii
at
carried
in
concentrations
determined
b
was
of ATP
tube
is
calculate
State
what
you
would
expect
to
happen
to
the
0.8 mm. Use
the
rate
concentrations
of
the four
the
and
substances
added
to
of
suspension
give
detailed
explanations
3
oxygen
uptake
in
mm
per
hour.
[1]
for
d
Explain
how
the
investigation
results
was
would
repeated
at
differ
17 °C
if
the
and
The
at
experiment
[2]
c
Predict
of
Explain
how
the
apparatus
would
be
used
answer.
[4]
was
repeated
but
no
phosphate
was
added.
37 °C.
e
your
what
oxygen
in
would
the
happen
to
suspension
the
and
concentration
explain
your
to nd
answer.
the
rate
valid
of
respiration
comparison
with
of
the
the
leaves
to
make
[3]
a
beans.
[3]
10
The
13
DNA
in
a
mitochondrion
polypeptides. These
(mtDNA)
codes for
polypeptides form ATP
clip
synthetase
and
parts
of
the
electron
transport
chain
U-tube
in
a
the
Explain
a
b
inner
membrane.
the
role
of
the
electron
transport
chain
mitochondrion.
i
Outline
how
in
[4]
these
polypeptides
are
produced
seeds
in
ii
a
mitochondrion.
[4]
Each mitochondrion has more than 13
polypeptides. Where are the rest produced?
iii
what
the
other
genes
in
[1]
mtDNA
code for.
X
c
coloured
water
Suggest
Mitochondrial
nuclear
genes,
[1]
genes
mutate
possibly
at
a
because
higher
of
the
rate
than
highly
bath
liquid
reactive
with
Figure 2.10.1
molecules
DNA.
these
Explain
mutations
in
in
the
the
matrix
likely
mtDNA.
that
interact
consequences
of
[3]
39
1
Bioenergetics
3.
1
Energy
and
Learning outcomes
nutrient flow
The
The
On
completion
of
this
section,
blue
Earth
be
able
define
the
habitat,
trophic
terms
a
ecosystem,
ecological
niche
as
state
Within
and
these
level
that
energy flows
large
border
they

as
and
is
not
that
there
quantities
they
are

explain
of
nutrients
in
chains
the
borders
organisms
also
open
adjacent
those
ocean
are
is
with
and
known
as
composed
as
ecosystems
a
interact
interact
small
with
community
with
their
each
as
biomes
of
a
which
of
that
have
ecosystems,
pond.
it
many
other
physical
offer
ecological
niches
fill
similar
niches
in
different
and
species.
Savannah
grassland
similar
which
and
Each
may
ecosystem
exchanges
species.
with
Populations
other
has
resources.
of
populations;
environment.
for
organisms
to
fill.
The
organisms
that
flightless:
ostriches
offers
parts
of
the
world
opportunity
for
are
large,
rarely
the
grazing
same
birds
so
are
in
Africa,
rheas
in
South
America
and
emus
ecosystems
and food
advantages
of
webs
Australia.
different
They
have
similar
ways
of
life,
occupying
the
same
niche
in
continents.
using
S tudy
food
regions
through
in
draw food
large
biomes
are finite
recycled

into
These
recycled
that
state
the
with
Ecosystems
ecosystems

divided
features.
to:
be

is
you
climatic
should
planet
foc us
webs.
Ecological
the food
niche
chain
–
the
and
role
of
a
species
interactions
with
in
a
community,
other
species
and
including
the
its
position
in
physical
environment.
S tudy
foc us
Energy
You
should
learn
these
flow
studied
definitions:
at
organisms

Species
that
–
a
group
interbreed
of
to
and
the
nutrient
ecosystem
and
between
cycling
level
the
are
as
two
they
processes
involve
community
and
that
can
interactions
the
abiotic
only
be
between
environment.
organisms
produce fertile
Energy flow
offspring.
Organisms

Population
–
all
the
individuals
for
the
same
same
species
place
at
living
the
in
same
gain
food
from
an
energy
source
or
sources
and
provide
energy
of
other
organisms
that
eat
them.
A
food
chain
shows
these
relationships.
the
time.
a

Habitat
–
organism
the
place
where
an
lives.
b
dead

Community
(of
all
–
trophic
all
the
levels)
leaf
earthworm
that
live
in
same
area
at
the
same
Ecosystem
–
a
primary
consumer
secondary
consumer
tertiary
consumer
time.
Figure 3.1.1

jaguar
c
producer
the
frog
organisms
a
A grazing food chain b
A detritus food chain for a forest ecosystem in
self-contained
Guyana c A generalised food chain identifying the trophic levels. The arrows show the
community
features
and
that
interactions
all
the
influence
between
physical
it
and
direction of energy flow.
the
them.
Each
organism
occupies
a
trophic
level ,
which
is
the
position
in
the
food
chain:

Producer
energy
S tudy
more
organisms
than
restricted
you
read
one
to
on,
are
able
to
ecosystem;
one
ecosystem
note
exist
others
examples
in
are
only. As
of
these.

autotrophic
simple
biological
Consumer
–
compounds,
consumer
organisms
and
40
an
organism
chemical
that
reactions
use
to
fix
either
light
carbon
energy
dioxide
or
and
foc us
produce
Some
–
from
a
molecules.
heterotrophic
usually
trophic
that
decaying
by
levels
obtain
organism
feeding
on
including
energy
organisms.
by
that
living
obtains
energy
organisms;
decomposers
breaking
down
–
there
in
are
organic
several
heterotrophic
compounds
in
dead
Module
Food
chains
are
simple
descriptions
of
energy
flow.
But
producers,
such
more
are
than
eaten
one
by
type
more
of
than
food
one
consumer.
organism.
There
Many
are
consumers
many
food
feed
chains
ecosystem.
A
food
web
gives
a
better
indication
of
all
these
foc us
on
within
In
an
most
ecosystems
webs
show
ecosystems,
too
but
complex.
trophic
much
(use
are
photosynthesis).
relationships.
Remember
Food
producers
different
phototrophs
feeding
Bioenergetics
as
S tudy
grasses,
1
they
The
levels.
energy
some
of
rarely
food
This
flows
the
is
as
complexity
show
chain
purely
and
all
these
food
by
feeding
each
relationships
relationships
web
qualitative;
indicated
show
there
as
energy
is
no
they
flow
in
become
not
between
indication
that
ecosystems
about
for
there
where
phototrophs.
details
of
See
vent
are
the
some
producers
pages
2
are
and
3
communities.
how
arrow.
large
sharks
sea
of
S tudy
carnivorous
otters
foc us
fish
octopus
Herbivores,
large
parasites,
crabs
carnivores,
detritivores
omnivores,
and
starfish
decomposers
(sea
small
stars)
scallops
are
all
consumers
as
carnivorous fish
and
abalones
they
invertebrates
are
all
heterotrophic.
and
sessile
invertebrates
sea
small
urchins
small
herbivorous
herbivorous
fish
invertebrates
microscopic
floating
animals
Link
detritus
kelp
algal
turf
The
(very
large
smaller
seaweeds)
Figure 3.1.2
(algae
seaweeds
growing
surface
of
cycling
of
nitrogen
is
considered
microscopic
over
floating
rocks)
in
algae
more
detail
on
pages
46
to
47
.
A food web for the kelp forest in the north-east of the Pacific Ocean. See
page 52 for more about this food web.
Respiration
During
is
not
100%
respiration,
surroundings.
efficient
much
Eventually
energy
all
the
at
is
transferring
transferred
energy
that
energy
as
heat
entered
from
to
an
food
to
A
TP
.
the
ecosystem
leaves
Summary q uestions
as
infrared
Earth
into
radiation
to
the
surroundings
and
is
radiated
away
from
the
space.
1
State
the
differences
energy flow
Nutrient
Nutrients
elements
called
are
the
to
make
nutrients.
inorganic
elements
building
required
mineral
simple,
recycling
cycling
form.
available
in
blocks
those
organic
organic
Autotrophic
Unlike
the
of
to
molecules.
organisms
energy,
biosphere
molecules.
there
is
They
Sometimes
absorb
a
finite
organisms.
If
contain
these
are
of
not
2
are
elements
quantity
they
they
the
in
life
comes
to
a
complete
niche
b
biome
c
these
the
a
between
habitat
and
ecosystem
and
community.
Explain
the
limitations
of food
standstill.
secondary
consumers
4
a
and food
State
each
dead
O,
primary
leaves, dead
ecosystem.
differences
and
population
chains
urine, faeces,
an
between
nutrient
recycled
3
then
State
in
and
the form
of
N
webs.
the
and
S
in
which
elements C,
are
H,
absorbed
by
consumers
bodies
producers.
b
producers that
use
mineral
nutrients to
make
State
one
element
molecules,
decomposers
break
waste
to
matter
mineral
such
as
amino
acids,
proteins,
use
of
each
biological
in
organisms.
etc.
down
5
release
nutrients
Suggest
birds
inorganic
pool of
mineral
nutrients,
e.g.
nitrate
of
why
sulphate
ions
in
the
soil
and
in
large, flightless
ions
and Australia
and
the
South America, Africa
are
different
waters
species.
Figure 3.1.3
Decomposers play an important role in recycling nutrients to producers
41
3.2
Ecological
pyramids
Relationships
Learning outcomes
pyramids.
On
completion
should

be
state
able
that
numbers,
flow
in
of
this
section,
biomass
horizontally
level
numbers
energy
is
shown
and
in
ecosystems
arranged
the
blocks,
blocks
are
displayed
with
centred
on
each
top
of
as
block
one
another
.
The
pyramid
simplest
shows
numbers
of
organisms
at
each
trophic
level:
as
Producers
are
at
the
base.
Primary,
secondary
and
tertiary
consumers
pyramids
are
identify
are
trophic
Pyramid of


a
levels
about
and
ecosystem
ecological
These
representing
trophic
to:
information
an
you
between
the
limitations
arranged
above
the
producers
in
the
same
sequence
as
in
per
m
a
food
of
chain.
ecological
pyramids.
2

Numbers

In
many
each
are
of
given
these
trophic
per
unit
area;
pyramids,
the
often
this
number
of
is
number
individuals
decreases
with
level.
tertiary
=
1

consumer
The
area
often
of
the
each
block
numbers
are
is
proportional
so
large
that
to
the
some
number
blocks
are
of
organisms;
deeper
than
secondary
=
90 000
others.
consumers
primary
Limitations
=
200 000
=
1 500 000
of
pyramids
of
numbers:
consumers
producers

Organisms

Some
treated
pyramids
support
Figure 3.2.1
are
large
are
equally
inverted
numbers
of
whatever
if
the
their
producers
primary
size.
are
large
(e.g.
trees)
and
consumers.
A pyramid of numbers for a
grassland ecosystem. The units are

They
usually
show
what
we
can
see
during
surveys
of
ecosystems;
numbers per unit area.
they
do
not
include
decomposers
S tudy
Make
by
your
own
should
graph

Numbers
often

Numbers
are
pyramid
draw
paper
so
the
it
is
of
1
numbers
on
page
pyramid
drawn
to
62.
the
ants

Juvenile

They
in
include
show
parasites
in
they
will
type
as
and
large
animals
often
of
parasites.
If
is
in
of
all
the
bacteria
your
gut
the
into
on
your
numbers
difficult
to
give
to
the
same
scale,
e.g.
all
feed
at
a
different
trophic
level
to
adults.
numbers
at
one
moment
during
the
year
,
in
time;
due
to
numbers
of
reproduction
some
and
species
migration.
biomass
This
takes
into
requires
account
taking
the
different
samples
of
sizes
organisms
of
at
organisms
each
them.
Dry
mass
is
often
used
since
plants
trophic
have
quantities
by
of
water
drying
the
depending
plant
on
matter
environmental
and
reweighing
conditions.
to
the
dry
mass
of
animals
is
easier
,
since
the
water
constant
content
mass.
of
tissues
does
about
not
70%
fluctuate
of
animal
as
much
as
that
of
plants.
W
ater
tissues.
billions!
S tudy
advantages
still
at
to
constant
weighing,
mass’
drying
again. This
Much
of
with
this
biomass
to
are
that
consumers
type
of
is
the
potential
indicated.
food
However
,
there
pyramid:
the
plant
the
material
level
–
wood,
is
not
bone,
always
hair
,
for
edible
to
the
organisms
in
the
next
example.
and
continues
Material
that
is
eaten
may
not
be
digested
and
so
therefore
does
not
until
provide
of
of
level
means

mass
pyramids
trophic
limitations
trophic
weighing
of
each
foc us

‘Weighing
42
and
skin
are
remains
huge
may
pyramid
done
available
the
often
would
The
drying,
numbers.
community.
weighing
represents
run
estimating
you
animal
and
and
have
Finding
counted
sampling
become
This
thousands
on
pyramids
varying
inverted,
depend
considerably
ecosystems.
level
numbers
as
parasites.
foc us
in
of
important
scale.
This
you
a
stages
Pyramids of
If
are
on
change
S tudy
which
foc us
answering Question
You
and
microorganisms,
energy
or
nutrients
to
the
next
trophic
level.
material

They
do
not
indicate

They
depend
how
much
energy
is
available
to
be
transferred.
constant.
on
sampling
and
estimating
so
may
not
be
very
accurate.
Module

They
do
not
standing
were
show
crop
taken;
–
as
changes
the
mass
numbers
with
of
of
time,
as
organisms
some
they
at
species
the
are
a
time
change
measure
when
of
the
the
Bioenergetics
secondary
=
1
=
4
=
10
consumer
samples
considerably
1
during
primary
the
year
,
so
does
their
biomass
in
the
ecosystem.
consumers
decomposers
Inverted
Both
pyramids
types
‘base’
is
of
and
pyramid
smaller
than
may
the
be
inverted,
primary
which
consumer
means
level.
In
that
the
detritivores
producer
ecosystems
such
as
producers
forests,
the
producers
consumers
producers,
that
feed
such
as
are
on
very
large
leaves,
compared
flowers,
phytoplankton
in
fruits,
the
open
with
the
bark
and
ocean,
many,
=
40 000
small
roots.
Tiny
reproduce
much
Figure 3.2.2
faster
than
the
larger
zooplankton
that
feed
on
them.
The
A pyramid of biomass for a
zooplankton
tropical forest ecosystem. The units are
graze
on
the
phytoplankton
phytoplankton
reproduce
but
so
are
continually
able
to
find
food
as
–2
the
fast.
S tudy
Pyramids of
It
is
more
can
be
done
foc us
energy
helpful
determining
).
dry mass per unit area (g m
the
by
to
understand
flow
of
energy
drawing
how
from
pyramids
an
ecosystem
one
of
trophic
functions
level
to
the
Draw
by
next.
and
This
on
energy.
your
own
energy
page
by
62.
pyramids
of
biomass
answering Question
Do
not forget
to
add
1
the
units.
Pyramids
the
of
energy
The
flow
time.
Producers
the
The
of
available
proportion
of
a
either:
stems,
level
much
becomes
is
the
at
energy
available
roots,
of
productivity
flowers
this
new
of
each
trophic
level,
or
levels.
consumption
absorb
content
the
trophic
trophic
for
this
leaves,
energy
show
between
productivity
becomes
of
energy
energy
each
content
trophic
as
sunlight,
for
primary
and
fruits
growth
is
of
level
but
the
over
only
a
that
are
made
in
form
year
.
not
heat
productivity.
confuse
all
this
plant
productivity
is
consumed
each
year
.
If
it
transfer
organic
were,
much
planet
would
not
look
so
green!
The
energy
flow
from
producers
during
to
consumers
is
less
than
the
productivity
of
the
producers
out
how
what
content
of
much
is
consumed.
consumers
of
what
organisms,
feed
they
e.g.
on
This
and
consume.
leaves,
is
energy
flow
estimating
The
found
energy
by
the
is
determined
quantity
content
burning
the
of
and
the
material
in
heat
of
is
is
used
to
a
record
the
in
temperature. The
energy
and
by
organisms
combustion
and
a
to
in
shows
water
with
measure
of
increase
primary
calorimeter
material. The
thermometer
the
a
colorimeter. Calorimeters
transferred
Not
foc us
of
Do
the
each
S tudy
that
period
small
consumers
primary
food
a
kJ
is
calculated
knowing
that
4.2 J
finding
energy
or
parts
oxygen
in
raises
by
the
temperature
of
1 g
of
water
1 °C.
a
calorimeter
.
S tudy
Pyramids
types
of
of
energy
pyramid
include
do
not.
the
The
dimension
units
for
of
time,
pyramids
which
of
the
energy
other
are
usually
It
–2
is
impossible
pyramid
The
advantages
organisms
blocks.
a
to
have
an
inverted
–1
year
kJ m
as
foc us
two
or
This
of
pyramids
parts
is
pyramid.
of
the
energy
organisms
best
They
of
way
show
to
that
do
are
not
have
represent
the
that
an
the
energy
the
size
effect
and
on
functioning
transferred
edibility
the
of
from
size
an
one
of
of
and
the
page
of
then
energy. Think
try
Summary
about
this
question
4
on
45.
ecosystem
trophic
Summary q uestions
level
why
not
to
the
few
next
food
enough
decreases
chains
energy
have
to
with
position
more
support
than
in
four
another
the
food
trophic
trophic
chain.
levels.
level
of
This
There
explains
simply
predators
that
is
1
Suggest
the
ecological
on
other
external
predators.
and
There
internal
will,
however
,
parasites
of
these
be
enough
large
energy
to
support
limitations
of
pyramids
of
2
Discuss
The
work
involved
estimating,
since
can
not
be
all
time-consuming
of
the
organisms
and
in
a
involves
sample
c
much
can
be
As
with
pyramids
of
numbers
and
biomass,
they
suggest
pyramids
pyramids
feed
only
on
the
of
numbers,
trophic
level
below
them.
of
of
biomass,
and
energy.
Explain
why
it
is
impossible
to
that
have
consumers
limitations
of
burnt!
3

the
pyramids
energy:
b

drawing
pyramids.
the
predators.
a
The
reasons for
feed
Many
an
inverted
pyramid
of
top
energy.
predators
often
feed
on
several
different
trophic
levels.
43
3.3
Ecological
efficiency
The
Learning outcomes
efficiency
of
energy
flow
between
energy
trophic
available
levels
to
a
is
calculated
trophic
by:
level
______________________________________
On
completion
of
this
section,
Ecological
you
efficiency
=
×
energy
should
be
able
describe
how
the
efficiency
transfer
between
shows
available
is
what
to
discuss
the
transfer
by
in
efficiency
of
energy
that
the
can
other
often
foc us
Y
ou
the
two
laws
thermodynamics from
be
are
organisms
Both
ecosystems.
as
heat
eaten
apply
Look
have forgotten
to
your
study
the
of
energy
the
consumed
energy
entering
by
a
one
trophic
trophic
level
level
is
in
by
as
body
they
maintenance
the
respire.
organisms
This
and
much
in
the
leaves
next
very
passes
little
as
to
the
new
growth
level.
them
Summary
losses
of
the
can
next
steep
from
The
trophic
energy
trophic
levels
available
level
and
to
for
decomposers
and,
consumption
explains
why
possibly,
limits
pyramids
of
to
the
energy
are
sided.
analyse
about
the
data
on
energy
flow
on
the
opposite
page
to
learn
up
and
if
of
energy
flow
in
ecosystems
shows
the
following:
in
you
then
question
this.
of
energy flow
them
also
very
Analysis

Producers

Ecological
4.
absorb
The
efficiency
between
much
energy
into
very
efficiency
well-managed

net
of
Much
of
more
answer
next.
ecosystems.
growth
S tudy
physics.
percentage
the
ecosystems.
There
Remember
100
level
determined
surroundings

trophic
trophic
used
levels
previous
of
is
energy
by
to:
This

consumed
crops
is
radiated

of
it
the
about
might
variable
than
atmosphere
is
it
consumers;
lower
little
light
1–2%
be
as
between
may
be
as
that
for
strikes
producers,
high
as
as
often
less;
in
5%.
producers
high
them.
and
20%,
consumers,
but
more
and
often
it
is
this.
Energy
their
is
used
body
by
organisms
maintenance
and
at
all
trophic
levels
for
movement.
productivity

gross
Only
the
energy
in
new
growth
and
new
individuals
productivity
(reproduction)
is
available
from
one
trophic
level
to
respiration
the

next.
Energy
is
transferred
to
the
surroundings
as
heat
37
44
when
organisms
respire
and
move.
secondary

Energy
is
transferred
to
detritus
food
chains
at
all
consumers
sresopmoced
trophic
131
levels.
175

faeces
–
105
Energy
transferred
surroundings
as
to
heat
detritus
is
food
available
and
biomass.
to
and
to
the
consumers,
so
280
limiting
their
numbers
750
1 478
dna

primary
consumers
In
open
to
other
ecosystems,
ecosystems,
serovitirted
consumers
(for
organisms
so
or
limiting
example,
their
energy
detritus
in
wastes
are
available
river
lost
to
ecosystems
1 890
3 368
is
carried
dead
faeces
–
downstream
bodies
sink
to
to
the
the
sea;
in
the
open
ocean
bottom).
800
Energy
4 168
flow
diagrams
are
another
way
5465
energy
25 833
flows
through
ecosystems.
producers
11 977
37 810
Figure 3.3.1
An energy flow diagram shows
1 700 000
the energy transferred between trophic levels
energy from
that
strikes
the
Sun
plants
in
and the ‘losses’ as heat to the surroundings
and as dead matter to decomposers. The
–2
the
44
chains
not
ecosystem
figures are in kJ m
–1
y
.
to
show
how
Module
1
Bioenergetics
Summary q uestions
1
The
table
shows
energy flow
through
a
crop
3
of
The
table
shows
energy flow
through
–2
potatoes. The
PAR
is
units
are
kJ
m
photosynthetically
wavelengths
between
–2
per
active
400
and
growing
radiation
season.
ecosystem. The
energy
intercepted
by
solar
leaves
energy
energy
PAR
transmitted
energy
leaf
transferred
organic
by
by
result
leaf
the
transferred from
transferred
stored
next
Ecological
to
photosynthesis
to
The
to
the
900
by
respiration
and
heating
to
herbivores
58
energy
transferred from
plants
transferred from
herbivores
to
leaf
72
litter
214 500
to
environment
as
environment
190 000
in
biomass
trophic
by
respiration
and
to
the
31
heating
and
available
transferred from
calculate
efficiency
the
herbivores
to
13
carnivores
24 500
level
=
potatoes
the
that
the
ecological
transferred from
percentage
is
available
of
to
by
carnivores
respiration
and
to
the
8
heating
efficiency.
the
the
energy
energy
living
next
transferred
to
decomposers from
92
organisms
level.
energy
2
1 946
respiration
the figures,
trophic
plants
transferred
environment
input
photosynthesis
energy
energy
Using
in
2400
energy
to
plants
compounds
of
energy
65 800
2400
energy
energy
woodland
600 000
surface
through
a
–1
week
input
environment
reflected from
kJ m
1 000 000
energy that cannot be absorbed (not PAR)
PAR
are
–
700 nm.
energy fixed
solar
units
table
shows
the
energy flow
through
a
transferred from
leaf
litter
to
153
decomposers
bullock,
–1
which
is
a
primary
consumer. The
units
are
MJ day
energy
transferred from
environment
energy
intake
energy
transferred
by
to
environment
in faeces
a
4.93
assimilated
Using
transferred
to
environment
in
urine
Draw
the figures,
transferred
respiration
and
by
to
environment
by
an
the
the
stored
next
4
in
trophic
biomass
and
available
to
10.29
page,
Ecological
input
to
trophic
calculate
efficiency
the
the
ecological
and
the
herbivores.
diagram
like
that
the
information
on
in
the
the
table
ecosystem.
Use
the
information
between
in
Figure
gross
3.3.
1
to
explain
productivity
and
the
net
productivity.
bullock
=
the
that
is
the
ecological
Explain
the
relevance
percentage
available
of
to
to
of
the first
energy flow
and
in
second
laws
of
ecosystems.
efficiency.
the
the
energy
6
Use
the
primary
trophic
foc us
information
efficiency
next
level.
S tudy
using
woodland
thermodynamics
the figures,
plants
level
5
Using
110
14.71
heating
difference
energy
calculate
the
energy flow
opposite
0.89
for
energy
to
heating
25.00
b
energy
and
30.82
efficiencies for
energy
decomposers
respiration
7
a
of
in
this
energy flow
consumers,
and
section
between
b
to
a
discuss
the
producers
consumers
at
and
different
levels.
Explain
more
why
many food
trophic
chains
do
not
have five
or
levels.
You will find ecological efficiencies of 10% given quite often.
b
Suggest
why
some food
chains
in
marine
This figure was derived from the original research done in the
ecosystems
may
have five
or
more
trophic
levels.
1940s and involved a miscalculation of the data. A study
8
Many
natural
and
man-made
habitats
are
green,
even
carried out in the 1960s found the transfer between primary
though
they
may
support
populations
of
herbivores.
consumers and secondary consumers to be about 1%!
Suggest
a
reason for
this.
45
3.4
The
nitrogen
The
Learning outcomes
cycle
element
compounds.
On
completion
should

be
able
explain

explain

describe
this
section,
identify
you
importance
in
the
the
is
your
an
important
knowledge
nitrogen-containing
(e.g.
NAD,
NADP
of
component
Unit
1
you
compounds:
and
A
TP)
and
of
many
should
amino
nucleic
biological
immediately
acids,
proteins,
acids.
of
S tudy
biosphere
term
From
these
nucleotides
to:
the
nitrogen
of
nitrogen
foc us
fixed nitrogen
Remember from Unit
how fixed
nitrogen
1
that
proteins
have
structural
roles
(collagen)
and
roles
is
in
metabolism
(enzymes).
Nucleic
acids
are
involved
in
information
storage
recycled
and

explain
the
importance
decomposition,
retrieval.
of
ammonification,
Nitrogen
gas
(N
or
dinitrogen)
forms
nearly
80%
of
the
Earth’s
2
nitrification,
deamination
and
atmosphere.
denitrification
in
the
cycling
it
nitrogen

explain
is
unreactive
oxygen
the
roles
microorganisms
of
is
As
it
has
a
triple
covalent
bond
between
the
nitrogen
atoms
of
and
respiration
named
and
of
environment
nitrogen.
oxygen,
available
dioxide,
many
).
(N
Nitrogen
carbon,
Most
is
most
are
readily
that
that
called
nitrogen
organisms.
However
,
molecules
somehow.
or
to
which
photosynthesis.
so
hydrogen
dinitrogen
not
carbon
component
recycling
and
it
is
by
nitrogen
must
be
is
to
this
organisms
an
with
in
important
absorbed
attached
fixed
enters
used
Compare
other
from
the
atoms,
such
nitrogen
to
distinguish
it
communities
in
ecosystems
as
as
from
2
Link
nitrate
ions
)
(NO
absorbed
by
autotrophic
organisms
and
used
to
make
3
amino
This
is
the
place
to
recall
acids.
of
biological
the
1.
Revise
nitrogenous
the
as
plants,
can
use
simple
forms
of
fixed
such
as
nitrate
ions;
heterotrophs
need
more
complex
forms
of
molecules
fixed
from Unit
such
your
nitrogen,
knowledge
Autrotrophs,
structure
nitrogen,
such
as
amino
acids.
of
compounds. You
Autotrophs
use
nitrate
ions
to
make
amino
acids.
They
reduce
it
to
+
should
apply
your
knowledge
and
nitrite
ions
)
(NO
and
then
to
ammonia
(NH
2
understanding
of
proteins
to
the
rest
reactions
that
)
in
energy-consuming
4
occur
mostly
in
chloroplasts.
Fixed
nitrogen
in
the
form
of
+
of
this
section
and
then
is
NH
answer
now
ready
to
attach
to
products
of
the
Calvin
cycle
to
make
4
Summary
question
S tudy
amino
1.
acids
in
the
chloroplasts
to
be
Autotrophs
foc us
group
Take
care
when
writing
from
In
this
book
the
element
refer
unreactive
gas
(N),
(N
of
acids
acids
amination.
the
for
rest
to
of
the
make
the
These
are
exported
from
the
organism.
proteins;
biosynthesis
they
of
also
purines
use
and
the
amino
pyrimidines.
),
and
decomposers
digest
proteins
to
amino
acids.
They
use
to
amino
acids
to
make
their
proteins.
The
processes
of
feeding,
dinitrogen
digestion
the
by
about
we
these
nitrogen
amino
amino
Consumers
nitrogen.
use
process
used
and
biosynthesis
of
proteins
continue,
along
food
chains.
and fixed
2
Consumers
nitrogen
(N
combined
with
of
atoms). Often,
if
you
just
their
it
may
not
be
energy
clear
to
acid
what
you
amino
proteins
acids
and
or
proteins.
therefore
all
Carnivores
these
animals
gain
break
most
molecules
that
they
do
not
need
for
biosynthesis
to
down
release
the
ammonia.
examiner
store
from
write
amino
‘nitrogen’
cannot
other
The
rest
of
the
molecule
is
converted
to
glucose
and
stored
as
mean.
glycogen
animals
or
is
respired
excrete
(see
ammonia;
the
Krebs
cycle
mammals
on
convert
page
26).
Many
ammonia
to
aquatic
urea
and
birds
Link
convert
You
studied
protein
synthesis
it
to
uric
in Unit
Decomposers
1.
See
Sections
1.3
to
1.5
in
Module
remind
yourself
of
the
break
down
all
materials
that
are
excreted
and
egested
by
2
animals.
to
acid.
They
also
break
down
the
dead
bodies
of
plants
and
animals.
They
details.
digest
They
proteins
also
to
amino
deaminate
acids,
excess
absorb
amino
them
acids
and
and
use
them
excrete
in
biosynthesis.
ammonia.
Some
Link
bacteria
use
production
There
is
more
nitrogenous
about the
of
as
a
source
ammonia
by
of
energy
these
and
convert
microorganisms
it
is
to
ammonia.
The
ammonification
excretion of
compounds on
page
110.
Ammonia
use
46
urea
does
ammonia
not
in
remain
their
in
energy
the
environment
transfer
reactions,
very
long.
oxidising
Some
it
to
bacteria
nitrite
Module
ions,
which
reactions
ions
is
they
and
excrete.
excrete
nitrification
oxidation
of
Other
nitrate
and
the
ammonium
bacteria
ions.
The
bacteria
ions
to
use
nitrite
conversion
are
nitrite
called
ions
ions
of
in
)
(NO
by
Bioenergetics
similar
ammonia
nitrifying
1
to
nitrate
bacteria
Nitrosomonas ,
2
which
lives
in
soils
and
fresh
water
with
available
oxygen:
+
+
2NH
3O
3
ammonia
oxidation
of
→
2NO
2
oxygen
nitrites
ions
+
2H
+
2H
2
nitrite
to
nitrate
ions
O
2
ions
hydrogen
)
(NO
by
ions
water
Nitrobacter,
which
also
3
Figure 3.4.1
lives
in
soils
and
fresh
water
with
available
This scanning electron
oxygen
micrograph of the inside of a root nodule
+
2NO
O
2
nitrite
→
ions
shows it is packed full of Rhizobium bacteria
2NO
2
3
oxygen
nitrate
ions
S tudy
In
both
cases
similar
to
the
the
oxidation
provides
light-dependent
stage
energy
of
for
synthesis
photosynthesis.
of
A
TP
in
The
A
TP
is
then
The
used
to
provide
energy
for
carbon
relationship
nitrogen
started
this
growth
of
factor
for
which
growth
fixed
These
energy
dinitrogen
The
story.
now
This
producers
containing
nitrate.
has
cycling
the
process
in
are
from
mass
is
Nitrate
is
form
fossil
nitrate,
nitrogen
which
the
to
are
an
farmers
compounds
produced
fuels)
is
is
important
ions
why
of
which
by
the
used
to
where
to
add
legumes
we
maintain
important
bacteria
is
similar
+
to
natural
discharges
O
2
the
known
is
as
a form
acid
→
in
forms
of
lightning
2NO
2
(HNO
)
of
and
symbiosis
mutualism.
limiting
fertilisers
such
Haber
as
ammonium
process
combine
in
hydrogen
and
NO
2
+
nitrogen
cause
H
2
O
these
→
fixation.
During
reactions:
HNO
2
3
Figure 3.4.2
Nitric
nitrogen-
(Rhizobium)
air
.
energy
N
of
producers,
fertilisers
thunderstorms,
recycled
ecosystems.
nitrogen
(mostly
from
Haber
of
in
been
between
fixation.
fixing
Fixed
foc us
ways
forms
nitrate
ions
in
soils
and
bodies
of
water
.
Many trees that grow on
poor soils in the Caribbean are legumes
3
like this poinciana, Delonix
Some
prokaryotes
are
able
to
fix
dinitrogen.
This
occurs
in
regia. The
anaerobic
supply of fixed nitrogen by Rhizobium
conditions,
These
they
requires
bacteria
use
to
use
make
the
enzyme
hydrogen
amino
to
nitrogenase
reduce
and
nitrogen
uses
to
much
form
energy.
ammonia,
gives it a competitive edge over other
non-legumes in nitrate-deficient soils.
which
acids.
S tudy
Some
as
of
these
Rhizobium
nitrogen-fixing
spp.
Denitrification
balance
this
loss
Pseudomonas
dinitrogen
is
so
live
the
of
use
that
inside
bacteria
root
conversion
nitrogen
nitrate
this
is
in
a
from
their
loss
of
→
NO
are
free-living
nodules
of
nitrate
the
fixed
NO
ions
to
transfer
nitrogen
→
N
2
O
soils;
others,
foc us
such
legumes.
atmosphere.
energy
3
of
in
→
dinitrogen,
Bacteria
reactions,
from
the
which
such
may
as
6
is
chemists;
if
you
Chemistry
reducing
it
to
for
biosphere:
help
that
in
occur
oxidation
N
2
Question
designed
ask
do
not
who
the
nitrogen
appeal
to
study
someone
explaining
to
to
in
does
changes
terms
of
states.
2
Summary q uestions
1
Use
the
examples
term
of
nitrogenous
compounds
to
explain
4
fixed nitrogen
Use
and
2
Outline
what
amination,
protein
putrefaction,
fixation,
3
Name
in
in
the following
synthesis,
5
deamination,
ammonification,
the following:
an
amino
most
nitrification,
which
has
excretory
H
common
protein
as
product
its
of
R
in
information
show
how
it
nitrogen
State
of
the
is
how
in
this
nitrogen
exchanged
importance
nitrogen:
Rhizobium,
iron-containing
acid
nitrogenous
the
the
to
is
with
section
cycled
the
to
in
draw
a flow
ecosystems
atmosphere.
processes:
denitrification.
plants;
the
happens
all
chart
protein
animals;
group;
the
mammals.
6
Find
the
the following
Nitrosomonas,
legumes,
oxidation
information
of
to
in
Nitrobacter,
the
cycling
Pseudomonas,
herbivores.
states
explain
of
nitrogen. Use
what
happens
processes
you
described
in
question
reduction
and
oxidation
reactions.
2
this
during
in
the
terms
of
47
1
Bioenergetics
4.
1
Ecosystems
are
dynamic
Organisms
Learning outcomes
interact
interactions
On
completion
should
be
able

name

explain
terms
of
this
section,
with
between
other
organisms
organisms
are
in
an
examples
ecosystem.
of
biotic
The
types
of
factors :
you

competition

cooperation

predation

disease.
to:
examples
what
is
of
with
organisms
of
the
same
and
other
species
ecosystems
meant
biotic factor
by
and
the
abiotic
factor
Competition

discuss
factors
how
biotic
interact
in
and
a
abiotic
There
is
water
,
energy,
competition
with
other
species
for
resources,
such
as
space,
named
and
nutrients.
This
can
either
be:
ecosystem

discuss
as
how
dynamic

interspecific
competition
–
competition
between
different
systems.

intraspecific
competition
–
competition
between
members
same
If
two
other
,
but
two
groups
of factors
one
the
their
the
survival
of
organisms
biotic factor
–
any factor
results from
the
results
of
the
different
physical
or
–
any
chemical
aspect
of
the
environment
species.
prey
known
means
that
each
competing
competitive
of
competitive
occupy
will
starve
competition
that
or
they
not
nd
will
ght
each
anywhere
to
niche
within
species
nd
an
ecosystem
themselves
is
occupied
excluded.
This
is
exclusion
exclusion
slightly
Republic
animals
as
but
resource
more
at
in
different
found
seven
avoiding
the
past
niches.
can
For
different
direct
partitioning
on
with
grazers.
different
others
about
compete
specialist
be
seen
example,
in
a
anolis
study
species
feeding
on
in
the
competition
(see
Question
with
5
on
each
page
other
.
This
63).
In
heights;
leaves.
together
,
In
each
other
tropical
there
the
being
for
forests
are
some
African
food.
there
that
at
have
grazers
specialise
savannah
specialists
Many
are
on
antelope,
feeding
on
evolved
that
eating
zebra
different
into
feed
on
plants
fruits
and
and
wildebeest
plant
species.
abiotic factors
Giraffes
page
species
the
means
or
coexist
on
of
which
Grazers
is
rarely
species
abiotic factor
There
requirements,
This
of
same
is
a
successful
other
Dominican
same
of
niche
intense.
that
activities
organism
This
principle
The
the

identical
be
in
environment:
another
less
species;
lizards,

will
that
the
influence
the
foc us
by
are
have
them
reproduce.
There
of
species.
species
between
S tudy
species
ecosystems function
feed
on
trees
at
a
great
height.
59.
Cooperation
Cooperation
Did you know?
within
bees.
Competitive
alien
species
invade
ecosystem. The tropical
Individuals
means
house
released
most
likely during the
work
some
soldier
ants
association
an
example
in
levels.
social
together
The
insects
for
the
best
such
example
as
benet
ants,
of
the
of
cooperation
termites
colony,
and
even
honey
when
native Antilles
by
by
do
not
bees.
get
This
a
chance
to
cooperative
breed,
as
is
behaviour
the
is
case
altruism
between
of
two
mutualism.
or
more
The
different
polyps
of
species
many
for
coral
mutual
species
benet
contain
algae
protection,
called
carbon
zooxanthellae,
dioxide
and
which
photosynthesise.
nitrogenous
waste
from
the
The
algae
polyps
competition
and
even
worker
gecko,
gain
Gonatodes antillensis,
individuals
and
1980s,
single-celled
is displacing the
in
exchange
provide
carbohydrate
in
the
form
of
sugars.
Coral
grows
predation.
near
the
There
sh,
surface
are
less
which
species
48
different
in
is
maybe
at
seen
gecko,
Any
Hemidactylus mabouia,
and
is
an
with
Curaçao
exists
species
exclusion often occurs
that
when
a
are
of
the
water
,
intimate
clean
them
obvious.
so
providing
mutualisms.
of
parasites
their
Sharks
that
are
infest
algae
with
often
them.
sufcient
attended
The
by
benets
light.
pilot
to
both
Module
have
a
variety
of
adaptations
to
nd
and
catch
their
prey.
Corals
Females
are
composed
of
many
tiny
polyps
that
have
stinging
cells,
which
of
the
smooth-billed
into
These
any
are
Ranging
small
sessile
across
Carcharhinus
barracuda,
the
animal
Chaetodon
comes
within
reach
of
their
in
the
same
nest
in
incubating
a
coral
perezi ,
reef
are
green
moray
barracuda ,
Coral
reefs
predators,
eels,
that
Sparisoma
parrotsh,
ocellatus .
larger
as
Gymnothorax
prey
on
viride ,
are
such
open
reef
funebris ,
herbivorous
and
spotn
ecosystems,
cooperate
sharks,
move
between
Eretmochelys
sh,
another
and
such
ecosystems
imbricata ,
that
such
as
feeds
the
on
hawksbill
is
parrotsh
algae
will
a
form
are
of
predation.
‘predators’
grow
to
of
occupy
On
algae
much
a
are
damaged
by
storms
of
and
reef,
grow
the
are
important
and
thus
in
grazing
Populations
Predators
more
of
restore
carnivores
rarely
usually
the
it
have
on
space.
much
is
the
birds
–
altruism.
attracting
animals
foc us
butterflysh
bare
This
rock.
and
Left
happens
does
ungrazed,
after
means
not
move
place. Coral
of
the
coral
is
lost.
seaweeds,
creating
space
for
that
an
organism
about from
polyps
have
place
to
limited
coral
as
they
move
their
Herbivorous
coral
larvae
to
catch
their
prey. At
to
trophic
level
is
coral?
ecosystem.
depend
any
of
all
young
turtle,
which
settle
the
as
tentacles
sh
turns
eggs. They
butterflysh,
movement
reefs
eggs
take
sponges.
coral
that
the
example
‘Sessile’
Grazing
their
and
to feed
S tudy
that
lay
tentacles.
predators.
Sphyraena
stoplight
that
ani,
they
Crotophaga ani,
re
Bioenergetics
Did you know?
Predation
Predators
1
effect
other
on
in
way
the
presence
controlling
of
prey
species.
populations
of
their
prey;
Link
around.
Nitrogen xation
within
the
root
by
Rhizobium
nodules
of
legumes
Disease
is
Pathogens
fungi
and
by
of
and
are
disease-causing
various
protoctist
expelling
balance
killed.
such
worm-like
parasites
their
with
as
that
their
recovered
which
in
often
the
parasites,
there
are
struck
cause
Many
losing
the
are
viruses,
infected
animals
epidemics
in
is
bleaching,
some
populations
Caribbean
Most
Coral
of
the
bacteria,
viral,
live
them
but
through
staghorn
them
not
the
nutrients
most
would
visible
not
be
components
recycled.
of
respond
in
a
not
sort
S tudy
being
Pollinators
Acropora
have
More
an
and
not
ecosystem,
visible
See
47
.
birds
plants
are
mutualism.
foc us
populations,
coral,
Populations
of
fungal
polyps
plants
to
sweep
the
1970s.
and
energy
that
as
by
example
page
since.
Decomposers
without
that
zooxanthellae.
Occasionally
cervicornis,
organisms.
animals.
an
are
in
such
as
bees,
moths,
bats
obtain food from flowering
return for
pollen.
Flowers
attract
pollinators
transferring
are
adapted
to
but
in
a
variety
of
the
ways.
detritivores,
such
as
crabs
material.
Decomposers,
produced
by
these
and
such
sea
as
cucumbers,
bacteria
and
which
fungi,
eat
feed
and
on
shred
the
dead
faeces
animals.
Link
The
effect
of
predators
on
species
Summary q uestions
diversity
1
Dene
2
Use
the
the
coral
terms
biotic factor,
information
in
this
abiotic factor,
section
to
draw
detritivore,
a food
Section
decomposer.
web for
in
ecosystems
is
explored
in
4.3.
a Caribbean
reef.
Link
3
Make
a
table
to
elds
used for
show
how
livestock
biotic factors
affect
tropical
rainforests
and
The
grazing.
recycling
such
4
‘Ecosystems
are
dynamic.’
Discuss
this
statement
using
examples from
two
named
the
dynamic
Study
an
ecosystem
organisms
each
other
at
close
different
and
mineral
is
elements,
another
nature
example
of
ecosystems.
ecosystems.
5
of
nitrogen,
at
of
least
as
how
to
your
trophic
they
school,
levels
interact
and
with
college
describe
their
or
home.
how
physical
they
Name
the
interact
environment.
with
benets
cycle
on
of
(see
page
Now
you
drawing
the
of
see
the
Summary
the
nitrogen
question
4
47).
49
4.2
Biodiversity
The
Learning outcomes
On
completion
should
be
able

dene
the

explain
of
this
section,
term
what
diversity and

different

number
of
species,

number
of
individuals
is
meant

genetic
We
species
genetic diversity.
live
been
At
the
history
one
became
sixth
when
was
the
extinct. Are
great
of
65
its
and
terrestrial
each
species
each
species
present
in
an
area.
of
great
of
Earth):
areas
ecosystems
many
biodiversity
the
on
are
species
to
(perhaps
tropical
Earth.
suffering
We
the
forests
also
severe
largest
and
live
in
there
coral
a
reefs
time
problems
and
has
are
when,
our
ever
two
of
thanks
activities
extinction.
country
biodiversity
or
even
the
is
a
catalogue
whole
world.
of
all
But
the
living
biodiversity
things
also
in
an
includes
diversity
of
habitats
and
ecosystems
in
an
area
and
the
genetic
within
species.
dinosaurs
we
entering
the
Ecosystem diversity
there
region
species
of
within
species-rich
simplest,
a
the
are
different
world
the:
the
Did you know?
top ve
time
history
many
Within
endemic
of
million
extinction?
The Caribbean
a
driving
diversity
ago
measure
great
the
years
a
ecosystems,
variation
the
most
area,
in
in
in
us,
are
been ve
last
is
by
to
Earth. The
area
biodiversity
Did you know?
extinctions
an
you
the
have
of
to:
ecosystem diversity,
There
biodiversity
and
has
is
many
one
of
‘hotspots’ for
a
Caribbean
different
terrestrial
Caribbean
region
marine
the
ecosystems.
country
with
dominant
ecosystems
the
Here
ecosystem
along
is
position
an
of
the
imaginary
many
is
open
coastlines
ocean.
and
cross-section
ecosystems
But
many
across
indicated.
the
marine
elfin
woodland
biodiversity. Think
dry
rain
about
coral
reefs,
mangrove
forest
swamp
seagrass
beds
and
rain
forest
swamps,
forest
tropical forests.
forest
hydrothermal
coral
vents
reef
mangrove forest
seagrass
bed
deep
sea
Figure 4.2.1
A line transect that crosses an imaginary island, showing many of the
ecosystems typical of the Caribbean region
The
importance
niches
many
others
that
different
and
S tudy
Figure 4.2.2
UK. There is also a dome for the tropical
biome and an uncovered area devoted to
temperate biomes. The project displays
some of the ecosystem diversity in the
50
ecosystem
ecosystems.
then
biodiversity
opportunities
listing
We
them
for
is
the
species
discuss
some
wide
diversity.
in
this
variety
The
book;
of
ecological
Caribbean
try
has
thinking
all.
foc us
Inside the Mediterranean
dome at the Eden Project in Cornwall,
biosphere.
of
provide
Species
richness
list,
greater
the
is
a
the
measure
richness.
of
the
species
diversity. The
longer
the
species
of
Module
Species diversity
Species
diversity
is
S tudy
simply
the
number
of
different
species
in
One
way
of
investigating
this
biodiversity
is
cataloguing
species
diversity
than
is
one
there
is
in
and
because
to
The
living
is
light
expend
Central
diversity
may
to
the
be
rare.
further
are
high
energy
and
is
warm.
only
40
in
the
you
case
resist
that
go
the
are
more
for
or
for
(no
pine
many
the
frost,
600
of
the
temperature
internally
from
diversity
snow
or
species
ice),
do
of
The
not
need
a
single
more
species.
aware
domesticated
of
Coleus
of
Many
animals.
and
the
wild
of
alleles
flowers
animals
diversity
Y
ou
can
of
than
heat
absorbing
it
birds
in
in
Genetic
an
is
the
sum
organism
diversity
of
of
or
a
all
in
a
the
species.
species
is
the
Canada.
diversity
genetic
body
foc us
genome
genes
of
a
within
the
genes
in
the
and
when
see
the
hibiscus.
plants
we
look
look
diversity
Similar
at
in
very
the
genetic
diversity,
a
they
different
species. All
do
have
not
the
all
alleles
the
the
individuals
same
have
of
genes,
of
of
those
the
same
genes.
We
plants
colouring
in
the
genome
similar
.
cultivated
all
species
alleles
are
generating
surroundings.
S tudy
but
of
endotherms
possibly
of
the
are
constant
forests
Genetic diversity
is
by
rather
their
genes
diversity
a
by
sum
Genetic
birds
other
endotherms
about
and
maintain
species
dominated
biodiversity,
and
However
,
two
natural
are
stable
abundance
one
the
habitats
round
There
in
more
changes.
is
by
which
extreme
year
to
they
Species
ecosystem
and
centres
too
details).
dominated
provide
north
for
an
able
Canada,
trees
all
makes
are
in
not
58
diversity
important
are
page
more
This
intensity
keeping
America
it
and
forests
conditions
of
as
species
However
,
tropics
(see
ecosystems
temperate
species.
list
important
Some
although
decreases.
species
element
species
tree
species,
there
limited
species.
other
a
considered
with
Florida
several
making
another
different
and
–
foc us
all
–
the
Bioenergetics
an
Mammals
ecosystem.
1
and
leaves
although
Link
not
so
obvious,
Genetic
differences
because
of
their
This
an
to
species,
adapting
to
is
be
also
important
changes
alien
and
natural
may
There
is
in
between
populations
range.
diversity
adapt
exists
in
biotic
evading
changes
populations
adapted
genetic
in
new
of
the
slightly
abiotic
same
within
factors,
predators,
such
resisting
salinity,
in
each
populations
temperature,
species
differently
diversity
providing
and
in
populations.
different
the
ability
competition
new
parts
strains
humidity
of
and
example
to
with
disease
rainfall.
you
estimated
genetic
variation
different
diversity
that
forms
intracellular
by
different
order
of
between
exists
(or
and
the
in
a
species
proteins.
variants)
of
extracellular
alleles.
bases
of
in
The
the
investigated
example,
proteins,
enzymes.
alleles
DNA
is
For
are
that
such
The
for
identifying
as
the
so
that
primary
forms
we
can
is
sickle
studied
that
polypeptides
population
–
in
amino
cell
in Unit
there
all
in
of
the
are
the
anaemia,
1.
It
is
about
900
haemoglobin
human
with
acid
slightly
sequences.
the
often
haemoglobin
different
sequenced
codes
by
populations
variation
different variants
different
The
of
haemoglobin
which
population.
with
as
An
exist
have
and
are
see
structure
coded
how
for
the
differs
variants.
Summary q uestions
1
Dene
the
terms
biodiversity,
ecosystem diversity,
species diversity,
genetic
diversity
2
Explain
within
3
Print
a
how
a
map
Explain
species
species,
different
4
a
of
types
what
may
diversity
be
you
ecosystem
think
is
an
ecosystem,
and
b
genetic
diversity
investigated.
the Caribbean
of
in
and
as
identify
you
meant
by
can
the
one
location for
as
many
list.
term
‘hotspot’
with
respect
to
Figure 4.2.3
biodiversity.
Amazona
The St Lucia parrot,
versicolor, is an endangered
island endemic species. This parrot was
5
Discuss
the
signicance
of
biodiversity.
bred at Jersey Zoo in the UK and
reintroduced to St Lucia.
51
4.3
Species
diversity
This
Learning outcomes
section
diversity
On
completion
should

be
state
able
that
related
to
of
this
section,
diversity
to:
species
the
of
important
you
diversity
stability
of
The
is
gives
species
species
within
most
you
is
some
decreased
diversity
an
examples
is
in
by
an
of
what
happens
ecosystem.
looking
at
the
Y
ou
when
can
effects
of
the
work
out
changes
how
to
the
ecosystem.
catastrophic
loss
of
species
occurs
when
the
dominant
species
disappear:
an
ecosystem


explain
how
increases
species
the
Hurricanes
diversity
interactions
in
loss
of
a
and
rich
chainsaws
and
diverse
destroy
mangroves
ecosystem,
most
of
with
the
which
is
almost
under
total
water
.
an

Coastal
development
has
destroyed
many
seagrass
communities
ecosystem
around

dene
the
term
conservation

the
Deforestation
range
of
Did you know?
topsoil
to
is
worst
example
of
loss
diversity
was
caused
by
niloticus,
of
into
the
Nile
perch,
Lake Victoria
in
to
rain
and
away,
become
the
It
300
has
led
species
to
of
the
loss
examples
of
200
temperatures
often
makes
and
it
for
The
often
a
wide
forest
the
impossible
floor
is
thin
for
the
same
or
show
one
what
invades
it
happens
or
when
a
experiences
a
species
disappears
population
from
an
explosion.
Following
and
typhoons
waters.
for
Huge
the
coral
or
larvae
so,
then
Sea otters
food
Enhydra
19th
the
as
web
sea
small
and
in the Great
of
whales
Barrier
Reef
the
the
20th
that
apex
Nassau
aggregates
to
catch
at
algae,
the
to
time,
if
which
become
the
explosions
recover;
a
are
the
the
have
sh
pivotal
occur
in
provides
adults.
numbers
happen
they
less
now
prey
of
in
on
fur
as
The
decrease
every
10
more
hunt
there
urchins
loss
otter
,
of
the
In
was
the
a
exploded
one
in
species,
food
herbivorous
are
numbers
are
sea
urchins.
web,
sh,
such
many
scallops.
ecosystems
their
sea
from
smaller
and
Pacic
and
sea
species
octopus
they
to
web
crabs,
and
the
their
forests.
loss
role
of
feeding
for
food
kelp
and
protected
but
position
hunted
of
of
the
abalones,
Epinephelus
grounds
times
Caribbean.
sh,
with
survive
some
consumer
were
larger
these
leads
biodiversity.
shows
whole
spawning
ecosystems
T
ogether
nutrients
being
known
preyed
because
of
as
increased
upon
keystone
in
the
by
latter
killer
overshing.
predators
throughout
herbivorous
41
catastrophic
grouper
,
at
to
the
not.
century,
may
time
increases
phytoplankton,
many
After
population
has
stipes
a
play
otters
of
Pacific
the
to
so
coral.
these
animals
large
that
Sea
Loss of
easy
ate
flooding
growth
starsh
secondary
invertebrates,
species.
The
a
Pacic,
the
coral
page
to
led
other
Organisms
half
the
If
may
as
change
otter
,
kelp,
it
on
lutris ,
numbers
this
eat
the
in the
century
striking
of
then
then
the
encourages
recolonises.
frequently
The
in
This
numbers
years
A keystone species – a sea
starfish
of
food
52
which
habitats
Lates
cichlid sh.
otter eating a sea urchin
high
many
microorganisms.
central
coastal
Figure 4.3.1
provide
and
re-established.
The Crown-of-thorns
Africa.
that
the
ecosystem
introduction
wind,
trees
animals
of
These
species
plants,
washed
ecosystem
the
removes
other
exposed
Perhaps
Caribbean.
to
has
The
population
with
other
it
intense
factors
at
striatusis ,
a
certain
been
loss
of
a
shed
large
of
almost
top
or
apex
in
smaller
has
pressure
led
to
coral
on
reef
the
explosions
feeding
this
is
time
sh
year
.
to
is
very
from
predatory
lower
it
extinction
predators
reefs
that
As
sh
trophic
losing
and
levels.
their
Module
Sea
In
urchins
coral
reefs
in Caribbean
prior
to
1983,
coral
the
reefs
was
thought
to
be
long-black-spine
a
keystone
sea
species
Diadema
urchin,
for
controlling
the
pandemic
on
the
reefs
and
for
creating
space
for
the
coral
larvae
to
on
1983
and
reefs
herbivorous
urchin
reefs
this
has
have
of
sh
not
is
it
recover
coast
a
to
to
to
some
Jamaica
to
of
original
higher
of
and
killed
Thanks
grazing
algal
lack
places
is
the
its
high
the
disease
Bermuda.
continue
result
due
in
to
recovered
the
is
pandemic
Panama
moderate
cover
whether
to
1984,
from
cover
levels
intensity.
Since
T
oday,
and
is
of
there
nutrients
Sea
algal
percent
of
overshing
numbers.
grazing.
the
99
to
covering
of
the
the
as
were
and
severe
few
the
The
by
reported for
disease
a
was
pathogen,
years,
no
one
a
mass
marine
die-off
most
but
likely
even
knows
organism.
caused
after
what
it
30
was.
whether
are
along
most
Caribbean
to
waters,
numbers
reefs
urchins
pandemic
most
debate
in
urchin
the
there
the
settle.
ever
In
is
algal
widespread
growth
Bioenergetics
Did you know?
This
antillarum,
1
or
beginning
the
north
decreasing.
Conservation
Conservation
designate
areas
are
species
as
a
restore
not
managed
are
their
is
just
protected
so
removed
habitats
habitats
catastrophes,
without
that
from
are
they
have
as
the
some
and
In
the
kept
by
eruption
it
in
is
possible
interference.
habitat
extreme
damaged
volcanic
cases
human
maintain
threat.
been
In
any
habitats
under
that
such
preservation.
area
zoos
to
often,
Some
botanic
gardens
conservationists
human
on
features.
and
cases,
More
action
or
by
natural
Montserrat.
Figure 4.3.2
Red lionsh, an alien species
that escaped into the Caribbean and is
Some
conservation
practices
are
not
so
benign.
The
red
lionsh,
Pterois
causing havoc on coral reefs as it eats
volitans,
originates
Caribbean
such
as
in
a
Belize
in
very
the
short
which
use
Far
East
period
divers
and
of
to
has
time.
spear
spread
There
them
throughout
are
to
the
programmes
reduce
their
many reef animals
in
places
populations.
Did you know?
In
Jamaica,
threat
the
from
Black
two
River
invasive
quinquenervia ,
and
Morass
plants
wild
–
ginger
,
is
the
a
large
freshwater
bottlebrush,
Alpinia
allughas ,
wetland
under
Melaleuca
which
are
Some
spreading
techniques
species
upsetting
the
balance
in
this
ecosystem.
There
is
no
substitute
for
can
go
remove
seriously
alien
wrong.
digging
Prickly
them
to
and
pear,
Opuntia spp.
invaded
out.
Nevis
Conservation
damage
simply
and
a
habitats
involves
encouraging
matter
that
interactions
protecting
of
are
survival.
preservation.
at
that
their
risk
of
sustain
species,
The
damage
It
habitats
is,
however
,
continued
or
loss
and
ecosystems
much
survival
involves
of
more
all
from
than
species
maintaining
and
the
was
introducing
eats
it. The
removing
the
them.
and
in
it
by
whose
in
pear from
then
moved
populations
the
caterpillar
succeeded
prickly
but
native
elsewhere
moth
moth
the
island,
attack
a
removed
of
on
to
Opuntia
region.
Summary q uestions
1
Suggest
2
Redraw
otters
3
Dene
b
Explain
Dene
5
Suggest
Find
a
7
the food
a
and
species
on feeding
4
6
why
the
the
why
out
report
Suggest
it
on
page
is
important for
41,
showing
the
the
stability
effects
of
of
the
ecosystems.
loss
of
sea
relationships.
keystone species
importance
term
human
web
term
the
diversity
of
some
keystone
species
in
their
ecosystems.
conservation
is
difcult
to
restore
habitats following
natural
catastrophes
interference.
about
the
explaining
why
damage
the
invasive
caused
ecological
plants
can
to
ecosystems
reasons for
cause
by
killing
serious
the
red
lionsh. Write
it.
damage
to
ecosystems
such
Figure 4.3.3
as
wetlands.
These attractive owers
belong to the invasive bottlebrush tree,
Melaleuca
quinquenervia from the Pacic
53
4.4
Maintaining
biodiversity
There
Learning outcomes
are
Intrinsic
On
completion
should
be
able
of
this
section,
many
state
the

to:
reasons for
for
maintaining
biodiversity.
reasons:
you
Some
people
should

reasons
1
believe
therefore
that
value
humans
and
have
protect
the
custody
of
organisms
the
Earth
and
that
share
the
planet
maintaining
with
us.
Others
go
further
than
this
and
consider
all
creatures
to
be
biodiversity
sacred.

discuss
the
importance
maintaining
of
biodiversity
it
important
describe
People
examples
of
also
on
planet
in situ

There
world
and
Direct value to
Many
of
the
bacteria;
roseus,
in
much
and
Many
Wildlife
Belize,
Our
who
is
Puebla
plants
in
if
climate
it
is
by
should
that
are
grade
ores.
and
of
the
not
by
religious
feel
beliefs.
‘connected
Many
to
also
believe
other
and
living
since
organisms
making
damage
and,
we
them
have
have
changed
as
much
right
hostile
where
we
to
can,
conditions
other

Organic

Plants

Soil fertility

Reefs
waste
to
organisms,
restore
it
so
that

Water
is
the
we
those
view
that
as
humans,
ancestors
hold
it
in
but
trust
are
for
we
just
have
not
renting
future
it
inherited
from
our
the
natural
descendants
generations.
study
drugs
Fish
near
organisms.
such
stocks
as
currently
can
be
Antibiotics
the
much
mass
are
Madagascan
interest
produced.
in
isolated from fungi
periwinkle,
cataloguing
Herbal
and
Catharantus
plants
remedies,
once
used
which
have
of
world
in
animals
the Caribbean
as
species
a
result
we
comes from
have
been
now sh
diversity. There
continues
countries
to
provide
as
the
diversity. The
genetic
disease
and
the
useful
are
much
or
other
spread
agriculture,
we
heavily shed
lower
many
down
amateur
inspiration for
use
quantities
provide
in
of
the
hot
dioxide
might
to
visit
of
need
in
continue
since
the food
the
is ltered
to
waters
contributes
maintained
mangroves
by
through
to
nutrient
protect
soils
to
17th
chain.. Timber
ornithologists
artists,
and
photographers,
to
of
popularity. Countries
their
maize
Many
National
grow
widen
these
in
the
is
the
states
of Oaxaca
diversity
relatives
are
of
spring
enzyme,
Taq polymerase,
in Yellowstone
chain
bacteria
may
and
broken
cycling,
coasts from
rock
reaction
are
used
help
to
reduce
threatened
to
Park. This
(PCR),
routinely
extract
was
enzyme
metals,
used
such
is
discovered
mass
e.g.
it
by
by forensic
as
in
a
produced
and
copper, from
the
effect
of
increases
in
carbon
dioxide
down.
cycle
to
provide
decomposers
us
enters
the
with
and
erosion.
before
and
cultivated
low
us:
and
water
as
Parks.
the
genetic
wild
such
crops.
heat-stable
polymerase
DNA. Other
services for
carbon
of GM
increased
relatives
catastrophes.
products. The
a
we
has
tourists
wild
resources
Thermus aquaticus, from
bacteria for
ecotourism
developed facilities for
genetic
many
added
in
widespread
lines.
domesticated
extinction;
appeal
many
much
absorb
is
that
similar
our
of
plants
biodiversity.
natural
provide
of
increase
material
transpire,
and
on
thrive.
our
we
do
atmosphere.
54
that
nature’.
people.
destruction
source
bogs
are
of
widespread
ecosystems
peat
loss
Rica
our
along
and
wild.
aesthetic
have
habitat
to
the
creative
can
provide
humans
income for
modied
scientists
Forests
that
isolated from
developed
globally
with
bacterium,
genetically
can
wildlife. The
they
the
other
Indirect value;
the
from
we
often
the
can
Taxus brevifolia. There
plants from
affected
change,
Organisms
been
they
be
and Costa
do
Mexico;
thermophilic

also
other
source
Dominica
crop
maize
a
tree,
if
species
enjoy
and
originate from
have
yew
see
appreciate
writers
use
the food for
and
many
people
poets,

to
may
of
we
drugs
extracted from forests
botanists

that
Pacic
animals
century

the
the Caribbean,
harvest

drugs
medicines
Although
is
we
in
humans:
anti-cancer
and
Chinese
is
as
much,
limit
organisms

that
believe
Earth
so
should
conservation.

originates
locally
exist

view
globally

and
is
This
supply.
drinking
nitrifying
water.
bacteria
(see
pages
46–47).
in
the
Module
best
The
Latin
way
to
conserve
any
species
is
to
do
so
in
its
natural
habitat.
RAMSAR
phrase
in
situ
means
in
their
original
place.
Maintaining
sites
habitat
means
that
all
the
life
support
systems
are
to
tends
to
concentrate
on
individual
species
or
groups
High-prole
programmes
have
centred
on
mammals,
such
pandas
and
whales.
Equally
important
are
ecosystems
threatened
the
most
popular
of
these
is
the
tropical
rain
be
are
many
other
,
less
well-known
at
an
international
Ramsar
Find
out
if
in
there
a
is
Iran
in
Ramsar
ecosystems
that
near
where
you
live.
should
conserved.
National
in
there
under
signed
forest,
site
although
the
are
by
1971.
development;
important for
wildlife. They
as
treaty
giant
be
of
of
designated
species.
wetlands
provided.
conservation
Conservation
are
the
considered
natural
Bioenergetics
Did you know?
In situ conservation
The
1
situ
area
and
international
conser vation.
of
land,
The
although
in
bodies
term
the
designate
National
Caribbean
by
Park
that
legislation
is
is
often
not
areas
applied
necessarily
of
to
land
a
the
for
S tudy
foc us
large
case.
The
International Union
Conservation

Morne
Diablotin
National
Park
is
in
the
northern
mountain
range
It
was
set
up
to
protect
the
habitat
of
the

Five
(Sisserou)
Blues
karst
Lake
Parrot,
National
limestone
with
all
an
endemic
Park
ve
in
of
bird
Belize
the
cat
is
the
conservation
200
bird
region

are
for
T
errestrial
Bonaire,
Nariva
areas,
particular
reserves
which
is
Phoenicopterus

of
about
an
area
species
of
found
100 000
in
that
acres
the
different
use
the
categories
and
then
of
website
to
research
some
country
and
vulnerable
species
species.
smaller
one
out
species.
from
Reserves
you
status
species. Try nding
endangered
and
Nature
tell
endangered
many
Imperial
of
will
of
about
Dominica.
website
include
home
ruber
wetlands
which
species
in
to
may
or
the
an
for
focus
on
providing
protecting
135
acre
a
flamingo
estimated
a
special
40 000
your
country.
protected
ecosystem.
sanctuary
Caribbean
on
flamingos,
ruber
T
rinidad
is
an
important
site
for
many
endangered
Summary q uestions
species,
It
is
including
both
a
RAMSAR
refuge
the
West
and
an
Indian
manatee
important
and
breeding
blue-and-gold
site.
It
is
a
parrots.
designated
1
Outline
the
reasons for
site.
maintaining

Marine
reserves
are
found
throughout
the
Caribbean.
An
example
2
the
Little
Cayman
‘no -take’
reserve
that
protects
one
of
the
biodiversity.
is
Dene
the
term
conservation
spawning
grounds
of
the
endangered
Nassau
grouper
(see
page
the
standards
world
and
of
management
the
region.
of
Some
parks
and
countries
reserves
have
the
varies
throughout
protection
and
careful
management;
resources
others
do
to
situ
conservation
does
not
just
involve
putting
a
line
area
of
natural
interest
and
preventing
Find
a
around
development,
shing
that
are
not
and
hunting.
designated
It
as
also
involves
special
areas,
enforcing
such
as
way
of
map
of
Rica.
the
measures
parks
or
List
national
the
parks
types
that
are
of
protected
by
logging,
national
parks
and
identify
in
any
areas
this
a
these
poaching,
in
biodiversity.
provide
ecosystem
particular
the
not.
of Costa
In
outline
involved
maintaining
3
excellent
and
52).
principles
The
in situ
last
reserves
endangered
species
that
are
of
protected.
one
sort
or
another
.
Examples
are:
4

reclaiming
and
in
ecosystems
natural
that
have
catastrophes,
been
such
as
damaged
volcanic
by
human
eruption,
Use
the
website
nd
the
endangered
of
the
IUCN
to
activities
hurricanes
status
of
the
and
following
and
also
outline
the
flooding
steps

creating
new
habitats,
for
example
by
allowing
vegetation
to
their
over ’
land
abandoned
by
people;
digging
ponds;
deliberately
taken
to
conserve
natural
habitat:
to
provide
new
surfaces
for
corals
to
setting
up
exclusion
zones
to
prevent
shing
at
certain
times
of
turtle,
particularly
during
breeding
Dermochelys
the
coriacea;
year
,
leatherback
colonise
sea

resplendent
quetzal,
seasons
Pharomachrus mocinno;

preventing
the
pollution
damage
to
or
placing
limits
on
levels
on
pollution
to
reduce
Amazon
parrot
issuing
be
permits
removed
Imperial
(‘Sisserou’),
ecosystems
Amazona imperialis;

in
manatee,
sinking
Trichechus manatus;
ships
them
‘take
to
from
companies
important
so
that
timber
ecosystems
and
without
other
products
causing
may
long-term
grouper,
pribby,
Nassau
Epinephelus striatus;
Rondeletia buxifolia.
damage.
55
4.5
Maintaining
Learning outcomes
On
completion
should

be
able
explain
of
this
section,
you
biodiversity
Some
species
is
a
not
from
are
realistic
their
so
threatened
option.
habitat
2
and
In
in
this
kept
their
case,
habitat
animals
somewhere
that
and
in
situ
plants
conservation
are
removed
else.
to:
the
term
conservation
Zoos
ex situ
and
why
it
in
conservation
is
Zoos
have
existed
for
thousands
of
years.
W
ealthy
people
used
to
collect
necessary
animals

describe
zoos
and
and
explain
botanic
maintaining
the
roles
gardens
of
Sometimes
animals
in
them
biodiversity
and

describe
and
explain
the
roles
banks,
sperm
banks
in
banks
these
plenty
them
were
of
space.
in
menageries
open
conned
Lympne
in
to
for
visitors
cages,
This
Kent
for
to
although
continues,
in
the
UK.
their
enjoy
more
two
Set
private
as
well.
by
In
many
enlightened
famous
up
enjoyment.
examples
John
cases
people
being
Aspinall,
large
gave
Howletts
these
zoos
of
opened
to
the
public
in
the
mid
1970s.
The
zoos
have
had
notable
and
success
embryo
keep
were
Port
were
seed
and
with
western
lowland
gorillas
and
have
introduced
captive
born
maintaining
animals
into
the
wild
in
Gabon,
W
est
Africa.
Other
zoos
are
owned
and
run
biodiversity.
by
zoological
functions
can
see
The

in
and
societies
addition
study
functions
protecting
with

of
up
captivity.
A tamarin from the coastal

zoos
researching
at
zoos
enjoyment
they
and
of
would
vulnerable
tamarins
programmes
example
the
the
that
These
and
not
have
a
variety
interest
otherwise
for
be
of
different
visitors,
able
to
who
see.
are:
breeding
good
groups.
providing
animals
breeding
A
successfully
Figure 4.5.1
to
other
endangered
captive
setting
or
Fota
is
Wildlife
biology
of
for
that
–
species
cheetahs,
Park
to
Jersey
Zoo
is
involved
Brazil
those
for
species
species
from
in
Cork
gain
a
that
which
in
will
are
breed
in
bred
Ireland
better
understanding
of
forests of Brazil. As their habitat has been
breeding
habits,
habitat
requirements
and
genetic
diversity.
The
destroyed they have been rescued, bred in
Zoological
Society
of
London
(ZSL),
like
many
large
zoos,
has
a
captivity and reintroduced to protected
scientic
reserves.

contributing
T
rinidad
S tudy
programme
method
of
conservation
organisms,
of
seeds,
an
tissues
or
any
organism
bank.
is
known
as
It
is
not
a
store
of
bits
educating
but
whole
ways
listed.
genomes
in
one
does
Sperm
Zoos
in
cheetahs
is
because
extinct
few
they
10 000
descended from
an
aim
of
the
the
nearly
years
survived. All
Maintaining
living
these
genetic
a
are
diversity
conservation
bit
being
only
individuals.
do
56
and
cheetahs
although female
by
the
to
the
USA;
Nariva
Swamp
Przewalski’s
in
collaboration
horse,
Equus
with
ferus
has
to
been
the
bred
very
Dzungarian
successfully
Gobi
Strictly
at
many
zoos
Protected
and
Area
in
where
the
this
public
wild
horse
about
became
wildlife
and
extinct
30
years
conservation.
ago
The
in
Belize
is
a
small
zoo
that
houses
Caribbean
rescued
animals
not
deliberately
school
take
students
any
about
from
the
the
wild.
wildlife
of
It
specialises
their
in
country.
banks
cooperate
do
not
so
that
become
breeding
inbred
–
programmes
a
risk
when
generate
genetic
maintaining
diversity
small
and
populations.
became
ago
species,
their
in
very
species
low
Zoo
of
Did you know?
diversity
in
Centre
educating
Genetic
V
alley
blue-and-gold
of
and
the
bred
a
Wildlife
DNA
Emperor
other

gene
The
captive
that
Mongolia
part
schemes.
re-introduced
gametes,
transferred
embryos,
ararauna ,
Zoo
przewalskii,
whole
reintroduction
successfully
Ara
Cincinnati
keeps
research
foc us
macaws,
Any
to
has
of
of
is
many
As
part
zoo
in
to
the
other
.
of
many
another
.
animals
A
much
for
many
years

Collect

T
est
breeding
This
kept
in
a
option
sperm
animals
inbreeding
captivity.
cheaper
in
programmes
prevents
Zoos
is
and
cooperate
collecting
bank.
The
are
and
sperm
process
transported
promotes
is
semen
from
suitable
the
sperm
for
motility.
(or
the
only)
males.
from
one
diversity
with
keeping
follows:
cheetahs
promiscuous!
consult
and
as
genetic
it
each
frozen
Module

Dilute
with
a
medium
containing
buffer
and
albumen
(a
plasma
1
Bioenergetics
Did you know?
protein).
San

Put
small

Store
volumes
into
thin
tubes
known
as
Diego
Zoo
facilities for
the
sperm
samples
in
liquid
nitrogen
at
sperm
(AI).
samples
Y
oung
cheetah
sperm
are
animals
and
a
of
then
over
Chinese
thawed
30
and
different
pheasant,
have
used
for
species,
been
articial
insemination
including
produced
cell
using
sperm
banks
damaged
lots
of
by
more
the
freezing
water
,
surrogate
which
Eggs
from
of
or
tends
to
stored
ice
in
and
that
the
more
They
are
large
of
zoos’
now
largest
sperm,
embryos
it
endangered
their
Frozen
Zoo.
not
foc us
confuse
cells
such
wild
placed
in
with
(IVF).
inside
reproductive
with
internal.
time
as
in
a
and
IVF
lab. The
small
ox
articial
(AI)
in vitro
In AI
the
sperm
are
as
be
embryo
hold
species
way
to
internal
until
including
vulnerable
same
likely
damage
frozen
technique
species
‘Frozen
and
much
are
then
This
many
antelope.
endangered
in
they
crystals
vitro
for
as
processes.
available.
used
African
many
be
freeze
form
fertilised
been
also
to
thawing
becomes
has
species
resources
can
difcult
are
mother
transplantation
different
embryos
are
membranes.
a
and
call
insemination
fertilisation
Eggs
the
from
S tudy
(oocytes)
sperm.
storing
cultures from
species. They
Do
Eggs
of
rhinoceros,
banks.
Embryo
one
–196 °C.
and
The
has
straws.
the female’s
tract
zygote
embryo
uterus
so fertilisation
occurs
and
outside
divides
is
the
is
body
to form
inserted
into
a
the
or frozen.
genetic
case
they
Link
should
ever
be
needed.
Many
Botanic
The
in
rst
1764.
gardens
botanic
It
garden
received
seeds of tropical
plants
orthodox. See Question
the
was
rst
established
breadfruit
in
the
trees
Caribbean
brought
in
from
St
8 on
are
not
page
63.
Vincent
T
ahiti
by
Summary q uestions
Captain
William
Bligh
(of
Mutiny
on
the
Bounty
fame).
1
The
roles
of
botanic
gardens
are
Dene
the
term
conservation

Protect
endangered
plant
species.
Many
Caribbean
countries
gardens
conditions
in
which
the
often
gardens
grow
are
the
species
endemic
to
each
if
Research
methods
cultivated
and

Research
to

they
new
in
of
2
suitable.
botanic
can
be
reproduction
gardens
be
growth
grown
in
so
that
maintaining
Discuss
appropriate
conditions
3
the
habitats
if
their
species
to
original
habitats
so
plants
habitat
where
can
has
be
introduced,
been
they
roles
become
and
very
rare
the
and
of
in
zoos
and
conservation.
limitations
botanic
conserving
perhaps
destroyed.
have
way
biodiversity.
gardens
Suggest
zoos
methods
this
species
propagated.
conservation
Reintroduce
can
and
justify
the
botanic

and
have
of
botanic
ex situ
to:
of
gardens
endangered
in
animals
plants.
or
4
Explain
the
meaning
of
the
term
extinct.
gene bank

Educate
the
public
in
the
many
roles
of
plants
in
ecosystems
and
their
5
economic
value
to
a
Describe
material
banks
Seed
is
genetic
and
kept
by
sperm
embryo
banks.
banks
b
Seeds
how
us.
are
storage.
collected
Many
from
seeds
plants
(known
in
as
the
wild
orthodox
and
are
seeds)
put
are
into
stored
dehydrating

storing
them
them
at
so
that
the
seeds
contain
only
5%
the
techniques
long-term
role
in
of
these
conservation.
by:
6

Explain
a
Describe
are
water
b
–20 °C.
how
stored
Explain
in
why
orthodox
seed
seed
seeds
banks.
banks
are
necessary.
Removing
remain
seed
water
viable
banks
removed
for
from
Collections
from
for
seeds
many
ever
.
Every
storage,
continue
slows
years.
ve
thawed
to
be
down
However
,
years
and
made
if
their
seeds
some
tested
metabolism
do
seeds
to
possible
see
to
not
from
if
‘top
so
remain
each
they
up’
sample
will
the
that
they
viable
in
are
germinate.
bank
for
each
7
Explain
why
records
of
animals,
have
zoos
the
such
limited
keep
careful
breeding
as
of
cheetahs,
genetic
that
diversity.
species.
57
4.6
Sampling
ecosystems
All
Learning outcomes
biology
classroom
On
completion
should
be
able
of
this
section,
you
explain

describe
describe
is
meant
how
to
to
how
laboratory
their
gives
natural
you
biodiversity
described
biodiversity
measure
eldwork.
makes
Much
much
of
more
what
sense
you
if
learn
you
in
the
study
habitats.
in
this
some
when
ideas
you
section
you
do
of
the
some
could
techniques
eldwork.
do
yourself,
you
Some
might
of
the
somewhere
use
to
techniques
near
your
home.
Species
richness
abiotic
Imagine
factors.
This
is
most
you
not
key
a
of
to
–
of
may
rst
some
and
of
for
and
soil
can
them
will
be
and
animals,
see
you
as
very
are
help
to
on
so
you
into
you
a
nd.
B,
a
etc.
some
and
to
you
Y
ou
of
live
of
others
ask
key
–
plant
take
plots
arthropods.
Many
forms
recording.
some
and
certain
If
the
identication
dichotomous
need
for
animals,
catalogue
use
different
do
search
length
not
could
identication.
be
be
is
small
On
time
the
photograph
land
Search
of
know
the
most
thoroughly
photographs.
in
newspaper
.
will
are
identify
collection
nd.
out
and
The
larger
identications;
these
plots
with
the
observation
species
small
which
of
your
that
you
to
it
of
much
A,
There
4.6.1).
ground.
Biologists
with
studying
probably
a
harder
spread
of
skills
of
identify
guide
(Figure
waste
some
list.
nd.
eld
species
will
to
common
within
make
many
they
a
species
to
is
species
good
look
animals
possibly
soil
most
different
task
photograph
some
and
photographs
from
not
area
the
just
plants
a
that
in
area,
rst
up
or
need
someone
animals
of
may
the
ask
The
you
Y
ou
small
those
quantity
You do not need to be
all
The
build
these
the
identify
common
Some
you
these.
and
of
that
large
organisms
this
Divide
like
the
drawings
one
do
record
them
the
and
questions.
T
o
are
species.
have
sight
names,
for
bird
use
samples.
habitat
conservation
species
name
species.
At
a
organisms
some
series
you
in
special
obvious
types
keys
are
a
particularly
Figure 4.6.1
the
do
sample
assess
to
section
assess
by
sampling
ecosystems

in
should
to:
what
qualitative
and
organisms
This

students
1
the
soil.
Search
arthropods.
Dig
up
through,
Other
ways
a
small
looking
to
catch
anywhere special to do eldwork. Every
small
arthropods
are:
patch of waste ground and vacant lot is an

ecosystem!
pitfall
lid
that

traps
level
prey
sticky
some
Y
ou
can
species
survey
about
–
a
line
line
it
they
you
hide
a
list
in
from
One
an
soil
intervals
see
sampling
are
(tape
or
parallel
looking
could
to
also
at
see
be
catch
of
These
the
tell
you
One
right
if
what
way
stretched
the
angles
is
to
in
it,
with
newspaper
into
insects.
much
be
as
do
across
the
the
it
in
a
wall
are
together
is
most
3.2
to
It
a
distributed
in
of
use
certain
use
the
of
obvious
to
repeat
may
your
not
Module
present,
to
to
number
species
area.
or
the
a
but
be
1.
not
line
could
also
be
an
road.
regularly
areas.
If
or
at
their
Aquatic habitats like this
distribution
seems
to
show
a
pattern,
can
you
think
of
a
reason
for
this?
pond make good places for sampling and
The
underlying
reasons
may
studying the adaptations of organisms to
their environment
58
its
so
trap
Cover
better
need
in
are
this
an
is
Y
ou
some
species
to
jar
up
fall
pyramids
to
species
clumped
It
example.
of
jam
biodiversity
year
,
limitations
that
flying
tend
for
a
rolled
jelly.
ndings.
measure
area.
rope)
or
your
like
with
predators
will
animals,
distributed.
jar
petroleum
throughout
the
jam
any
that
as
something
the
from
board
include
of
place
Fill
such
can.
present
round;
they
along
random;
if
and
level.
can
make
rarely
year
hole
species
methods
imaginary
Figure 4.6.2
a
regular
how
a
soil
material
species
all
transect
W
alk
–
names
and
present
These
traps
make
at
dig
the
species
sticky
scientic
different
–
with
interaction
between
the
two.
be
certain
biotic
or
abiotic
factors,
or
an
Module
1.
cylindrical
flat,
2.
leaves
blade-like
leaves
3.
4.
5.
6.
strap-shaped
less
leaves,
leaves
in
pairs
leaves
in
whorls
leaves
with ne
leaves
with
at
than
teeth
leaves
4–15 mm
less
than
leaf
apex
tapers
apex
does
than
of
the
the
long
40 mm
long
stalk
edges
to
to
2
go
to
3
go
to
5
go
to
4
Halophila decipiens
Halophila johnsonii
wide
Thalassia testudinum
wide
one
not
go
Halophila engelmanni
edges
4 mm
leaf
top
on
leaves
40 mm
greater
the
smooth
leaves
go
point
taper,
to
6
Ruppia maritime
leaf
tip
has
three
teeth
Halodule wrightii
Figure 4.6.4
Figure 4.6.3
Bioenergetics
Syringodium liforme
or
blade-like,
strap-shaped
1
An ecosystem dominated by
seagrass off the coast of Honduras. This
A dichotomous key for some Caribbean seagrass species
sh has its mouth open awaiting cleaner
sh to remove its parasites – an example
of mutualism.
Abiotic factors
There
are
numerous
interactions
between
organisms
in
an
ecosystem
and
S tudy
abiotic
are
factors.
associated
These
with
a
often
limit
collection
the
of
range
of
physical
an
organism.
conditions.
Coral
absorbs
Make
calcium
from
water
,
using
it
to
make
calcium
carbonate
to
form
a
list
Molluscs
do
the
same
thing.
Forests
modify
the
is
much
canopy
forest
less
of
the
than
the
floor;
wind
in
forest
as
a
speed
open
that
result
is
reduced;
ground;
little
there
is
so
the
much
available
are
many
effect
light
for
is
any
epiphytic
of
rainfall
on
absorbed
plants
that
species
by
the
and
Humans
influence
Examples
have
had
such
as
the
red
branches
of
making
lionsh
bauxite
bromeliads
almost
direct
obvious
–
effects
it
all
influences
on
possible
(see
extraction,
page
are
directly
dynamiting
shing,
reefs.
alien
and
But
species
causing
runoff,
we
to
and
also
the
effects
oil
spills
have
all
affected
coastal
on
marsh
and
coral
reef.
These
invade
indirectly.
and
as
When
dredging,
indirect
sewage
which
effects,
happened
Sediment
effluent,
ecosystems,
chemicals
are
each
one.
the
you
foc us
carrying
should
minimise
including
abiotic
out
always
the
a
study
do
effect
your
you
like
this
best
have
to
on
the
with
environment.
Do
not
unnecessarily
and
trample
from
and
if
you
disturb
the
oil
e.g.
by
taking
soil
to
where
you found
samples,
mangrove,
return
salt
of
on
habitat,
from
that
and
the
grow
growing
have
pollution.
industrial
ecosystem
examples.
are
for
fertiliser
orchids
ecosystems
coral
53),
and
abiotic factors
soils
S tudy
trunks
the
a forest
environment
explain
considerably:
of
the
influence
skeleton.
foc us
Ecosystems
factors,
although
them
it
them.
is
humans
Species
that
are
not
distribution
to
is
investigate
influenced
a
measurements
is
or
more
plant
of
by
the
linked
to
of
a
in
water
the
presence.
throughout
abiotic
species
soil
their
biotic
distribution
one
for
evenly
determined
of
species
responsible
distributed
the
by
distribution
plant
are
and
water
factors.
species
For
wetland
content
soil
abiotic
named
factors.
a
ecosystems.
Y
ou
see
example,
area?
to
and
see
if
Y
ou
the
Their
may
if
this
what
could
be
asked
Summary q uestions
is
limits
the
1
take
be
distribution
of
the
a
record
could
line
the
Y
ou
out
in
see
There
begin
in
might
oxygen
be
an
study
absence
of
At
species
measure
walking
your
area.
the
and
cylinder
.
merely
This
the
intervals,
and
the
now
line
investigations
take
e.g.
a
volume
makes
soil
of
your
observing
much
the
more
1
metre,
sample.
the
abiotic
recorded
factors
anemometer
,
marine
concentration
that
are
habitat,
Explain
why
salinity
then
of
a
list
small
such
as
would
area
of
a forest.
with
you
a
can
samples
of
wind
3
Air
and
as
a
list.
species
Suggest
hygrometer
.
use
meters
to
If
4
you
important
when
to
use
compiling
Suggest
study
the
of
limitations
biodiversity
other
factors
be
record
the
compiling
we
soil
can
is
names
assessing
distribution.
speed
it
scientic
that
investigation
quantitative
important.
thermometer
,
humidity
ecosystems,
and
a
species
natural
any
with
a
Y
ou
water
section.
other
be
the
sample
make
next
can
or
or
soil
than
to
with
freshwater
across
measuring
the
temperature
measured
the
a
rigorous
can
shall
presence
squeeze
comes
more
transect
how
compiled for
content.
2
T
ake
Explain
a
species
list
without
information.
how
biotic
influence
plants
of
by
on
a
and
the
abiotic
distribution
wetland
ecosystem.
water
.
59
4.7
Sampling
Biodiversity
Learning outcomes
On
completion
should
be
able
of
this
ecosystems
section,
you
present
in
T
o
an
take
might
to:
an
explain
what
is
meant
state
what
is
meant
species
by
abundance
the
species
locally
or
of
presence
is
by
W
ays
a
organisms
of
extremely
globally.
making
only
rare
of
is
one
and
list
also
or
on
assessing
of
species
important.
two
the
the
individuals
edge
of
biodiversity
assessing
abundance
as
well
as
need
to
distribution.
standard
piece
of
apparatus
for
assessing
abundance
of
plant
species
species
density
the
quadrat.
There
are
different
types
of
quadrat:
and

percentage
the
simply
sampling
is
frequency,
the
example,
that
either
assessed
by
The

be
ecosystem;
indicate
include
quantitative
not
extreme
extinction

should
2
an
open
frame
quadrat,
which
is
a
square
of
known
area.
A
typical
cover
2
school

explain
the
advantage
of
using
a

gridded
a
described
in
0.25 m
which
is
divided
by
wires
into
smaller
sections,
10
larger
quadrat,
marked
surveys
are
out
carried
with
out
tapes.
qualitative
1
the
and
ecosystem
that
were
diversity
1000 km
in
by
the
over
Amazon
very
much
region
was
larger
areas.
assessed
For
with
1000 km.
this
quantitative. You
remember from Unit
between
×
biodiversity
quadrats
techniques
are
is
foc us
example,
section
quadrat,
10
much
Some
The
quadrat
index.
perhaps
S tudy
college
a

diversity
or
should
difference
quantitative
data.
A
small
certain
The
quadrat
species.
abundance
percentage
This
it
gives
of
This
quadrat
in
you
the
is
nd
size
several
to
walk
for
of
For
animals
the
numbers
the
of
do
of
animals
is
area
and
that
a
the
calculate
are
size
area
cover
is
of
of
–
assess
as
be
the
the
the
the
distribution
of
recorded.
species
each
frequency
–
what
species.
species.
quadrat
Gridded
that
percentage
sometimes
area,
the
recorded
by
to
can
of
is
quadrats
occupied
the
area
of
make
by
each
the
occurs.
length
and
is
timed
the
ground
absence
covered
the
plant
this
specic
the
is
the
or
species
assess
through
a
times
the
to
on
percentage
abundance
present,
put
quadrat
which
way
be
presence
indication
easy
species.
simple
of
the
no
relatively
The
can
The
of
count.
counting
time.
sedentary
or
of
the
time
each
mobile,
to
assess.
identied
of
each
One
the
species
species
chosen
different
for
very
have
number
actual
numbers
not
difcult
you
the
The
abundance
mean
more
After
will
species.
that
depend
Repeat
on
this
species.
use
a
quadrat
and
count
2
times
unit
with
area
Some
ACFOR
Another
a
or
as
can
far
way
too
how
will
or
give
to
so
apply
to
be
use
mark
of
In
case
of
before
you
mobile
This
can
use
per
rst
or
scale
how
their
have
done
actual
of
is
as
this
record
making
the
it
such
much
you
population
is
plants,
T
o
how
Once
than
numbers
scale,
rare).
description;
several
density
abundance
quicker
a
the
Repeat
mean
species
example.
them.
small.
calculate
the
an
are
occasional,
for
far
numbers
and
you
present
recordings
estimate
and
each
‘frequent’,
they
count.
frequent,
to
have
your
number
quadrats
plants
common,
rst
if
0.25 m
numerous
animals
to
This
individual
make
e.g.
positioned
‘common’
certain
area,
species.
decide
plants
you
catch
are
isolate
to
abundance
that,
each
(abundant,
have
many
for
to
that
randomly
species
difcult
you
within
counts.
animals
sample
(S
is
to
).
1
Release
some
these
time
animals
later
.
This
back
is
the
into
the
second
environment
sample
(S
).
and
It
repeat
should
the
catching
contain
some
2
marked
individuals
and
some
unmarked
individuals.
The
smaller
the
Link
number
an
Use the
9
on
equation to
page
of
marked
estimate
of
the
individuals,
population
the
size
larger
by
the
using
total
the
population.
Lincoln
Calculate
index :
answer Question
number
63.
in
S
________________________________
2
population
size
=
number
in
×
S
1
number
marked
in
S
2
60
Module
Y
ou
could
collect
a
small
quantity
of
each
species
and
weigh
them
to
you
biomass.
are
If
you
then
studying
you
can
estimate
draw
the
numbers
pyramids
of
present
numbers
in
and
the
foc us
ecosystem
biomass.
The
This
Diversity
symbol
index
that two
index
Σ
means
different
indices
are
used
to
assess
species
diversity.
They
individuals
quantitative
samples.
One
you
could
use
is
known
as
of
not
can
will
belong to
species or
group.
(Often
it
identify organisms
diversity.
of
the
count
the
randomly
sample
possible to
to their
Many
of ’.
Simpson’s
is
index
a
sum
probability
involve
a different
taking
‘the
measures the
selected from
Many
Bioenergetics
nd
S tudy
their
1
whole
plants
individuals.
area,
students
in
on
waste
some
that
so
we
Barbados
grow
It
in
would
have
to
They
take
take
counted
ground.
waste
the
ground
too
long
samples.
number
recorded
are
to
In
of
their
individual
count
this
each
all
plants,
the
plants
example,
species
results
in
in
this
so
we
in
species
so they
are
identied
to
genus or family.) Use this
example
to
answer Summary question
4b.
some
10
quadrats
table.
Summary q uestions
2
Species
Number of
Number of
plants
each
in
10
quadrats
(n)
individuals of
species
number of
(n)
(n/N)
1
÷ total
individuals
In
studies
be
(N)
using
important
samples.
40
0.
154
to
take
Explain
necessary
thick-leaved
quadrats
and
it
may
random
why
this
suggest
is
how
you
0.0237
would
do
this.
grasses
2
thin-leaved
150
0.579
0.3352
Describe
grasses
species
be
Pride
of
Barbados
3
0.012
0.00014
5
0.019
0.00036
18
0.069
0.0048
15
0.058
0.0034
3
heart
seed
ways
abundance
in
of
a
poppy
Evaluate
the
a
named
the
cress
piece
points
wild
dolly
11
0.043
4
0.0018
In
a
of
who
sage
17
0.066
0.0044
259
for
of
(A
to
numbers
these
Tree
formula
animal
habitat
may
obtained
carried
diversity
by
the
on
ground. When
should
as
give
good
criticisms.
trees
in
a
dry forest,
identied ve
E). They
in
out
a
tree
counted
large
quadrat
0.3738
with
The
you
well
students
species
the
Totals
as
into
waste
survey
some
black
the
and
results
students
evaluating
wild
which
determined.
investigation
Mexican
in
plant
calculating
Simpson’s
index
of
diversity
results:
species
Number
is:
2
D
In
this
(D)
is
example
1
When
–
the
number
should
waste
is
index
high
realise
ground.
invertebrates
Complex
stable
loss
not
on
can
62
small
1)
this
The
resist
We
or
the
(near
0)
is
below
shows
another
very
but
high
as
how
of
on
very
species
the
low
made
or
for
any
the
diversity
actual
of
keystone
the
are
of
species
more
and
structure.
B
48
the
C
12
on
D
6
E
3
the
such
as
mammals.
alien
are
56
you
groups,
and
A
mean?
When
plants
from
that
diversity
this
course,
likely
is
apex
be
a
the
Simpson’s
diversity for
the
trees
index
in
the
forest.
dependent
by
b
Explain
using
predators
Question
Calculate
of
the
such
affected
See
to
species,
any
communities
species
community
Of
other
recover
of
does
diversity.
birds
introduction
or
index
What
diversity.
surveyed
ground
the
ground,
a
only
stability
the
loss
effects
is
)
gures).
high
damage,
the
on
is
not
the
such
that
waste
there
a
have
with
(Σ(n/N)
signicant
environmental
seen
1–
calculation
and
alone,
have
in
2
there
students
catastrophic
for
(to
changes,
Research
have
page
that
diversity
change.
is
plants
0.63
(near
above
species
change.
the
=
communities
and
of
of
0.3738
=
4
and
on
a
the
data
advantage
on
species
abundance
diversity
in
of
richness
calculating
index.
example.
61
4.8
Practice
exam-style
questions:
Ecosystems
Answers to
1
The
all
table
exam-style questions
shows
investigating
a
one-day eld
data
collected
terrestrial
by
can
be found on the
accompanying CD.
students
ecosystem
d
during
Studies
a
trip.
less.
10%
Trophic
level
Numbers
Biomass
2
per
e
per
5 842 424
the
efciency
levels
why
this
most food
Discuss
m
of
in food
energy
chains
efciency
is
transfer
is
not
10%
more
or
than
chains.
advantages
show feeding
[3]
of
drawing food
Explain
how
relationships
energy ow
in
and
an
webs
to
ecosystem.
nutrient
[2]
cycling
809
are
Primary
Explain
in
that
trophic
2
m
f
Producers
show
between
708 624
37
important for
sustaining
ecosystems
to
remain
as
self-
units
[4]
consumers
4
Secondary
354 904
The
of
11
starsh,
rocky
consumers
the
Tertiary
3
Pisaster ochraceus,
the Californian
shores
starsh
in
mussel,
the
were
is
the
main
predator
Mytilus californianus,
western
coasts
removed from
an
of
on
the USA. All
area
of
rocky
1.5
shore
(A)
in
1963
and
in
subsequent
years. The
consumers
effect
the
a
Use
the
data
in
the
table
to
draw
two
on
graph
was
paper.
i
Discuss
the
reasons for
the
shapes
of
The
how
starsh
graph
it
is
possible
to
have
on
were
not
lived
area
removed. After
dominated
shows
the
the
rocky
on
(B),
area
several
years
A
number
of
numbers
and
shore
of
after
species
removal
in
the
two
of
inverted
P. ochraceus
pyramids
that
another
[5]
areas
Explain
animals
the
pyramids.
ii
of
with
[4]
M. californianus
b
diversity
compared
pyramids
where
on
species
shore
biomass.
from
area A.
[3]
20
The
at
students
each
also
trophic
investigated
level
on
the
the
day
of
energy
available
their eld
18
trip.
with
c
Suggest
how
The
at
the
and
using
endemic
nowhere
their
of
to
[4]
draw
a
pyramid
each
trophic
level
results.
Explain
why.
species
else. There
level.
able
is
are
one found
many
on
island
one
in
to
the
14
12
[1]
10
island
8
6
endemic
4
species
in
Pisaster
16
energy
rebmun
island
not
productivity
ecosystem
An
trophic
were
the
fo
show
2
each
students
determined
seiceps
available
d
they
without
Pisaster
the Caribbean.
2
a
Suggest
an
explanation for
the
existence
of
many
0
endemic
species
in
the Caribbean.
[4]
0
b
Explain
why
it
is
important
to
conserve
1
2
3
4
5
6
7
8
9
10
these
time/years
endemic
c
Some
a
endemic
gardens.
botanic
gardens
species
Discuss
may
the
are
conserved
difculties
encounter
in
by
Explain
the
Explain
conserving
it
b
is
nitrogen
between
habitat
and
important for
and
the
terms
sulphur,
elements,
to
be
[4]
such
recycled
ecosystems.
as
the
with
in
the
on
an
[2]
it
Outline
the
available
should
ways
in
plants
include
answer.
62
to
the
which xed
in
terrestrial
role
of
nitrogen
is
in
species
diversity
in
area
B.
likely
in
on
was
studies
role
of
P. ochraceus on
the
rocky
the
Canis lupus. The
taken
[4]
on
energy ow
Lake Superior. The
island
preyed
in
upon
wolves
by
A
[3]
the
was
by
the
a
were
only
out
large
moose,
Alces alces,
population
received
carried
about
of
1%
wolves,
of
the
moose.
made
ecosystems. You
microorganisms
change
area
ecosystem.
island
energy
c
the
1970s,
herbivore
and
in
that
shore
In
ecosystem.
Compare
Explain
[3]
differences
why
carbon,
a
that
species.
ecological niche,
b
[3]
plant
botanic
these
3
species.
in
your
[5]
c
Discuss
the
in
the
implications for
results of the two
this
question
apply
in situ
ecological
to
other
conservation
if
studies described
ecosystems.
[3]
Module
5
There
are
many
species
Caribbean. Some
threat. Seven
small
patch
of
live
these
of forest
Republic. All
of
in
Anolis
species
at
lizards fed
lizards
ecosystems
La
in
insects
the
and
the
are
were found
Palma
on
in
that
9
under
living
in
mark–release–recapture
estimate
a
Index
Dominican
other
The
is
sizes
one
population
of
mobile
method
and
it
is
of
1
Bioenergetics
technique
is
used
populations. The
estimating
calculated
the
to
Lincoln
size
of
a
as follows:
small
S1
× S2
_______
estimated
arthropods,
but
they
were
distributed
at
population
=
different
nm
heights
in
the forest.
where
a
Suggest
how
seven
different
lizard
species
S1
=
number
in rst
prey
on
the
same food
animals
can
all
in
the
same
ecosystem.
Describe
the
implications for
and
released
=
number
captured
in
second
sample
[3]
nm
b
marked
sample
exist
S2
together
captured,
that
the
=
number
of
marked
animals
in
second
in situ
sample
conservation
of
lizards
if
this nding
applies
to
In
species
on
other Caribbean
islands.
a
set
c
Outline
the
roles
of
zoos
in
the
study
conservation
up
small
islands.
a
Explain
b
Discuss
the
term
the
biodiversity
c
i
Explain
biodiversity.
effects
in
of
[3]
abiotic factors
it
is
important
to
Outline
to
the
steps
conserve
that
Ecosystems
a
Explain
are
[5]
a
[3]
b
Moths
again. Of
governments
Use
what
context
of
is
meant
ecosystem
as
can
take
[4]
dynamic
by
Outline
FIVE
different
is
a
dynamic system
ways
in
Describe
how
the
in
of
damaged
by
changes
in
moths
hawk
biodiversity
such
You
which
a
Explain
c
Explain
an
ecosystem
the
biotic
and/or
why
reasons for
refer
to
‘Coral
maintaining
named
biodiversity.
ecosystems
and
the
reefs
every
estimate
Moths
the
in
of
had
number
the
the
could
be
many
terrestrial
is
been
of
population.
population
[1]
size
improved.
moths,
is
important
animals
size
of
in
their
[1]
invertebrate
not
well
catalogued
to
identify
the
the Caribbean
species
and
populations.
recover from
unless
ten
about
[4]
they
catastrophes,
occur
such
as
more frequently
years.’
the
differences
are
Discuss
reefs
what
before
we
we
can
need
help
to
them
[3]
a
Explain
the
importance
of
producers
in
the
between
in situ and
of
ecosystems.
[3]
ex situ
Some
students
counted
organisms
at
different
[2]
ways
genetic
of
storing
genetic
use. Gene
banks
are
levels
and
information
embryo
of
banks
stores
particular
are
in
a
dry forest
and
drew
a
pyramid
information
of
numbers. Suggest
why
their
pyramid
was
the
with
many
more
primary
consumers
species.
than
banks
coral
recover.
inverted,
examples
producers.
[3]
of
The
students
then
studied
a
rain forest
and
banks.
discovered
Explain
how
gene
banks
are
used
in
of
endangered
animals.
of
many
tropical
species,
on
such
as
cocoa,
are
cannot
known
be frozen
as
recalcitrant
and
stored
in
seeds
seed
plants
of
these
species
must
be
banks. The
grown
International Cocoa Gene
Research Station
a
collection
of
over
11 000
on
Explain
Bank
in Trinidad
cocoa
parts
of
the
rather
told
than
them
on
that
the forest oor. A
these
and
that
he
plants
had found
195
are
species
one
tree
of
the
genus,
Ficus.
the
than
advantage for
on
plants
of
living
the forest oor.
on
trees
[2]
is
Discuss
how
species
diversity,
such
as
that found
and
tropical
rain forests,
is
related
to
the
stability
trees from
of
different
species
in eld
in
has
producer
as
d
at UWI’s Cocoa
trees
scientist
rather
gene
many
banks.
c
The
the
epiphytes
growing
they
were
coconut
called
and
there
[5]
research
Seeds
that
the
living
conservation
d
17
species
of
c
caught,
set
[5]
possible future
gene
it
invertebrate
trophic
Sperm
marked
were
abiotic
answer.
banks
complete
night,
traps
may
conservation.
for
moths
the
[5]
b
Gene
the rst
night
estimate
hawk
the Caribbean.
functioning
b
on
[4]
may
your
were
named
10
in
of
as
to
this
for
know
Discuss
38
Hawk
of
than
a
traps
elephant
[3]
factors.
8
of
results
hurricanes,
be
light
Large
the
system.
stability
total
how
The
d
c
moth,
Eighty
systems.
biology.
dynamic
a
Elephant
estimate
ecosystem
hawk
caught
Suggest
of
b
of
reserve.
were
these
Large
conserve
biodiversity.
described
species
released. The following
animals,
7
a
nature
marked.
biodiversity.
ii
up
on
the Caribbean.
why
a
[4]
and
6
in
of
Hawk
species from
of
[2]
ecosystems.
[3]
world.
Explain the importance of eld gene banks for
cocoa and other crops with recalcitrant seeds.
[4]
63
2
Biosystems
1.
1
Introduction
Learning outcomes
maintenance
to
Transport
Flowering
On
completion
of
this
section,
be
able
plants
dene
the
context
term
of
and
different
mammals
parts
of
are
their
large
organisms
bodies.
Think
with
about
long
the
distances
heights
of
the
to:
tallest

systems
you
separating
should
transport
transport
in
the
multicellular
Also
trees
think
Earth,
on
Earth
about
and
the
and
the
their
blue
distance
extensive
whale,
from
its
the
root
largest
heart
to
systems
animal
the
tip
of
(see
to
its
Figure
have
ever
1.1.1).
lived
on
tail.
organisms
Cells

explain
why owering
mammals
need
a
plants
and
transport
often
system

outline
the
For
the
differences
transport
owering
systems
plants
and
need
between
a
constant
multicellular
If
long
distances
example,
this
is
near
cells
in
the
the
cells
from
surface
energy
as
and
owering
sources
require
the
of
of
such
from
animal
obtained
cells
supply
organisms,
of
raw
materials
plants
the
and
substances
oxygen
so
that
surroundings
by
simple
the
body
will
receive
a
they
to
survive.
mammals,
that
can
they
aerobically
.
then
supply
.
large
are
require.
respire
diffusion,
suitable
In
cells
All
only
the
the
other
of
the
body
will
have
to
respire
anaerobically
,
and
as
we
have
seen
this
mammals.
is
inefcient
and
will
will
activity
and
organic
compounds,
be
not
supply
wasteful
such
of
as
enough
food.
energy
The
sucrose
to
leaves
and
of
amino
support
plants
acids.
a
high
make
These
level
of
complex
compounds
Link
are
Look
at
about
page
how
anaerobic
energy
to
37
to
remind
inefcient
respiration
and
is
yourself
made
from
assimilates.
seeds
fruits
and
at
supplying
Most
multicellular
(e.g.
gills
or
exchange
carries
is
a
good
foc us
animals
idea
and
substances
could
sh
look
and
which
the
look
plants
at
their
transport
insects
which
how
other
and
the
in
the
is
great
to
ways
in
and
differ.
plants
but
These
gases
spaces
the
photosynthesis
distances
respiration
to
and
have
cell
specialised
in
system
the
respiration,
glucose,
So
not
the
are
known
roots,
as
owers,
growth.
body.
the
amino
carry
The
of
transport
in
acids,
also
gas
exchange
from
gas
also
reverse
of
food
minerals,
carries
the
system
the
absorption
fatty
system
for
oxygen
dioxide,
site
acids,
transport
structures
to
carbon
from
the
is
of
the
transport
for
oxygen
through
body
solid
to
all
the
vitamins
nutrients
and
–
systems
and
for
carbon
water
and
dioxide.
air
even
structures
trees.
movement
organisms.
This
up
one
diffuse
plant
seemingly
trunks
specialised
have
throughout
systems
in
mammals
is
tissues
the
of
bodies
achieved
and
transport
organs
systems.
of
by
that
These
are:
mammals
–
consisting
of
plants
are
known
a
a
as
system
blood
vessels
as
owering
plants
–
transport
systems
word
and
the
of
xylem
tissue
and
phloem
phloem
described
blood,
heart
consisting
vessels. Xylem
circulatory
and

tissue.
plant
Figure 1.1.1
vascular
and
stems,
foc us
systems from
often
of
substances
and
are
for
transport
distances
have
do
simply
within
through

meaning
gas
for
a
every
diffuse.
nutrients,
make
vascular
to
waste
specialised
owering
them
animals
and
Similarly,
too
water
T
ransport
Transport
lungs)
Flowering
like
S tudy
need
in
long
bodies. You
mammals
they
made
transported
water
.
systems
and nd
resemble
in
at
transport
around
they
ways
to
that
surface
direction.
cells
It
phosphate
are
wasteful
cells.
S tudy
triose
These
tissue. The
regions
of
xylem
These
systems
rely
on
the
movement
How does water get to
of
the tops of these giant redwood trees,
and
phloem
in
stems
and
leaves
are
uids
inside
tubes
in
a
single
direction.
Sequoia
known
as
vascular
bundles.
This
flow
64
type
of
transport
is
known
as
mass
sempervirens, and how do
plants like this absorb enough ions
from the soil to make all this biomass?
Module
This
table
compares
the
Feature of transport
nutrients
transport
systems
systems
of
owering
Flowering
plants
and
sucrose
others
amino
water
in
transport
plants
Mammals
glucose
acids,
of
respiratory
gases
the
ions
(minerals)
amino
no
xylem
(supply
dioxide
spaces
transported
xylem
tubes
is
in
of
by
and
sap,
oxygen
xylem
–
carbon
through
phloem
sap
of ow
phloem
sieve tubes
to
prevent
loss
of
Y
ou
sieve
may
be
asked
to
make
sections
of
plant
oxygen
and
carbon
dioxide
arteries,
capillaries
pull
heart
pumps
hydrostatic
and
veins
transport)
blood,
giving
it
a
pressure
pressure ow
faster
production
uids
–
blood
(extracellular
slower
wounds
vitamins,
blood
transport)
transpiration
–
acids,
air
(cohesion–tension)
phloem
the
yes
acids, fatty
(minerals)
cells)
(intracellular
mechanism
and
diffusion
xylem vessels,
sealing
maintenance
mammals.
ions
rates
Biosystems
transported:
carbohydrate
uid(s)
2
of
callose
to
seal
phloem
blood
clotting
tubes
material
to
stain
and
view
Summary q uestions
the
different
stems
that
tissues,
are
especially
almost
the
xylem.
transparent,
such
Good
as
materials
balsam,
for
this
Impatiens
are
balsamina,
1
and
stalks
of
celery,
Apium
graveolens .
These
stalks
are
in
fact
Dene
the
elongated
petioles
of
celery
leaves.
The
stem
of
a
celery
plant
the
term
transport
in
the
is
context
of
multicellular
very
organisms.
short,
and
the
at
parts
of
the
leaves
are
raised
into
the
air
by
the
long
2
petioles.
Explain
why
owering
If
you
are
going
to
look
at
your
sections
under
low
power
with
a
mammals
plants
need
and
transport
hand
systems.
lens
in
a
or
dissection
microscope
sections.
This
single-edged
microscope
at
medium
should
razor
be
they
or
done
blade)
and
do
high
with
you
not
need
power,
a
ver y
should
you
to
sharp
take
be
need
thin.
to
blade
care
For
cut
(such
while
viewing
ver y
as
thin
3
a
Explain
why
systems
cutting
the
plant
are
intracellular
sections.
blood
transport
described
whereas
system
in
as
the
mammals
is
extracellular.
Y
ou
can
and
then
stain
the
remove
sections
excess
with
stain
toluidine
with
lter
blue,
paper.
leave
Add
for
a
a
few
little
minutes
glycerol
4
(glycerine)
and
then
put
cellulose
pink/purple
a
coverslip
on
top.
T
oluidine
blue
List
the
similarities
differences
a
colour
and
lignied
walls
of
xylem
a
bright
can
some
also
nasty
look
at
plant
chemicals,
so
cells
in
instead
macerated
it
is
best
to
tissue.
use
Macerating
with
a
or
small
put
something
volume
of
suitable
water.
T
ake
a
like
lettuce
some
small
or
tinned
amount
celer y
of
in
the
a
fr uit
slide
with
water
and
a
coverslip.
Examine
under
low
and
a
microscope.
cells.
Look
net-like
you
for
Y
ou
xylem
thickening
nd!
should
vessels
in
their
be
able
with
cell
to
their
walls.
see
individual
characteristic
Y
ou
may
be
cells
liquid,
high
or
rings,
surprised
Outline
how
oxygen,
reaches
the
respiratory
put
cells
in
a
gas,
the
on
of
a owering
plant,
and
power
groups
spirals
by
and
or
b
of
plants
blender
root
a
transport
of owering
mammals.
uses
5
vegetables
between
blue.
systems
Y
ou
and
stains
muscle
of
a
mammal.
of
or
what
a
6
Make
drawings
distribution
plant
of
stems,
to
show
xylem
roots
the
tissue
and
in
leaves.
65
1.2
The
uptake
There
Learning outcomes
On
completion
should
be
able
of
this
of
section,
water
are
four

absorption

movement
state
that
of
to
water
transport
and
ions
in
plants:
from
the
soil
of
water
and
ions
over
short
distances
within
organs
to:
roots
take
up
ions
diffusion
and
stems
and
leaves)
by

facilitated
aspects
ions
you
(roots,

and
long-distance
transport
of
xylem
sap
and
phloem
sap
from
roots
to
active
leaves,
etc.
transport


explain
how
carrier
proteins
evaporation
Plant
root
hair
cells
and
move
ions
by
state
that
roots
of
water
vapour
from
leaves
to
the
atmosphere.
roots
absorb
ions
and
water
from
the
soil.
T
o
achieve
this,
they
absorb
the
following
adaptations:
active
transport

loss
the
have
endodermis
and
in
water
by

long
tap
roots

extensive,

fast
that
reach
branching
sources
root
of
systems
water
that
and
ions
occupy
at
large
depths
in
volumes
the
of
soil
soil
osmosis

explain
how
down
water
a
roots
absorb
potential
of
water
growth
ions
gradient.

of
phosphate
which
epidermal
branching
ions
are
that
mobile
cells
with
roots
to
remain
in
the
root
seek
new
bound
to
sources
soil
of
ions,
particles,
especially
unlike
nitrate
soil
hairs
that
increase
the
surface
area
for
absorption
S tudy
foc us

Facilitated diffusion
and
both
use
thin
thin
cellulose
carrier
carrier
proteins
about these
hair
movement
by
looking
1. See
also
at
across
2.7
6.2
in
cell
1 of Unit
Root
hairs
Further
module.
an
cells
and
for
are
away
near
from
impermeable
Ions
are
channel
in
the
the
Root hairs of thyme, Thymus
Root
is
soils
Did you know?
hair
are only
is
roots
infected
as
by
for
host
assimilates. This
cell
surface
also
membranes
have
many
of
special
as
aquaporins.
where
root
hair
the
epidermis
cells
die
and
is
permeable.
they
are
replaced
by
ions
so
are
are
interior
through
have
uptake
low,
require
pass
membranes
of
of
energy
respire
the
carrier
proteins
concentration
by
transport
facilitated
charged
for
active
ions
uptake
aerobically
available
than
to
in
have
of
ions.
of
of
in
cell
ions
to
diffusion
by
of
and
some
order
attracted
ions.
provide
and
Some
breathing
The
A
TP
.
well-aerated
aerobically
uptake
muds
with
bilayers
through
the
cell.
respire
active
phospholipid
active
absorbed
oxygen
for
The
use
positively
cannot
anaerobic
ions.
plants
also
the
there
cells
not
of
contain
waterlogged
soils.
is
species
roots
In
In
these
enough
mangrove
trees
(pneumatophores),
can
oxygen.
diffuse
There
are
throughout
large
is
the
air
root
spaces
within
the
roots
so
tissues.
a
in
(see
return
symbiosis
legumes
page
water
is
Roots
than
are
the
surrounded
root
hair
by
cells.
bilayers,
soil
water
,
There
so
is
water
which
very
is
has
limited
absorbed
a
higher
water
movement
through
of
potential
water
aquaporins.
through
W
ater
and
from
the
soil
down
a
water
potential
gradient
by
osmosis
into
47).
root
66
in
they
absorb
plant
between
bacteria
ions;
known
less
absorb
moves
Rhizobium
of
roots
phospholipid
similar to that
have
symbiotic
phosphate, which
transferred to the
they
short
part of the
(mycorrhizae). These
such
cells
these
Absorption of
ions,
particles;
are
especially trees,
oxygen
fungi
in
not
the
which
available
live
which
plants,
proteins
tips
tips,
do
very
Some
cells
there
energy
that
cells
soil
distances
ions
hair
charged
conditions,
have
also
mitochondria,
Many
water
,
root
root
for
proteins;
negatively
sp. (× 40)
Root
them.
channel
hair
channel
for
and
proteins
soil
absorb
story.
between
tissue.
charged
membranes.
Root
extend
diffusion
absorption
proteins
Absorption of
Figure 1.2.1
can
so
membranes
Module
in this
that
walls
methods
channel
of
hairs
cell
proteins.
root
Remind yourself
root
active

transport
very
hair
cells
through
the
aquaporins
in
the
cell
surface
membranes.
the
Module
The
pathway
taken
by
water
and
ions
from
root
hair
cells
to
the
xylem
2
Biosystems
in
S tudy
the
centre
cell
walls
of
the
and
root
is
the
intercellular
one
of
spaces
least
resistance.
through
which
There
water
are
and
plenty
ions
having
to
go
across
cell
membranes.
This
is
the
can
pass
this
point
Some
water
and
ions
will
enter
cells
and
pass
from
cell
to
1.2.2.
the
This
interconnecting
is
the
symplast
plasmodesmata
as
you
can
see
in
and
should
water
revise
potential from
cell
2.8
through
you
apoplast
osmosis
pathway.
foc us
of
At
without
maintenance
in
Module
1
of Unit
1.
Figure
pathway.
soil
soil
water
particle
root
hair
xylem
vessel
Figure 1.2.3
The Casparian strip around
each endodermal cell is a barrier to
movement of water and ions in the
apoplast pathway
Did you know?
apoplastic
Figure 1.2.2
The German
route
symplastic
epidermis
route
cortex
endodermis
botanist
(1818–1887) rst
Water and ions travel from root hair cells to the xylem tissue along cell walls
and from cell to cell through plasmodesmata
impermeable
Robert Caspary
described
strip
that
this
bears
his
name.
Summary q uestions
S tudy
foc us
1
Explain
and
Plasmodesmata
interconnect
movement
animal
all.
small
and
page
holes
cytoplasm
between
cells
See
are
by
cells
you
75 for
is
may
more
that
through
is
controlled.
wonder
about
the
cell
wall. Adjacent
continuous from
No
whether
these
similar
plant
cellular
cell
to
cell,
structure
cells
are
ii
exists
2
between
‘individual’
cells
Distinguish
and
tissue
in
roots
is
i
ions,
at
the
the
pathways
apoplast
across
root.
interconnections.
What
and
vascular
absorb
soils.
between
symplast
their
central
roots
cells
although
3
The
how
water from
surrounded
by
the
endoder mis,
are
role
ions
plasmodesmata?
in
movement
across
the
of
root
State
water
to
the
a
xylem.
single
layer
of
cells
that
controls
the
movement
of
ions
from
the
cortex
to
4
the
xylem.
The
cell
walls
contain
suberin,
which
is
an
Explain
by
substance
that
does
not
allow
water
and
ions
to
ow
the
role
performed
impermeable
between
the
the Casparian
strip
in
the
cells.
endodermis.
Instead,
everything
young
roots,
and
known
is
control
this
what
as
has
to
travel
suberinised
the
Casparian
passes
into
the
through
strip
is
strip .
central
the
visible
This
cytoplasm
in
cross
allows
vascular
of
the
sections
the
cells.
of
the
endodermis
In
root
5
When
low
to
tissue.
rate
roots
oxygen
of
cell
xylem.
ions
surface
This
enter
diffusion.
Figure
ion
Some
in
1.2.2).
carrier
into
creates
these
endodermis
the
selected
membranes
a
cells
ions
the
The
the
pass
uptake
proteins
carrier
from
can
are
the
endodermal
concentration
apoplast
endodermis
by
low
of
walls
all
the
pathway
of
ions
specic
through
proteins
of
in
at
for
the
a
in
cells
way
in
from
without
the
certain
hair
pump
endodermal
the
the
cortex
soil
entering
endodermis
symplast
root
the
cells
ion
or
is
into
cells,
by
to
cells
more
the
(see
selective,
Ions
have
so
in
that
already
an
in
soils
of
ions
with
the
decreases.
explanation for
this.
the
facilitated
water
any
ions.
pathway
ions
kept
concentrations,
uptake
Suggest
The
are
that
pass
been
6
The
roots
trees
of
grow
which
have
potentials.
trees
are
water,
these
many
in
very
low
Suggest
adapted
and
mangrove
anaerobic
b
a
obtain
muds,
water
how
to
these
absorb
oxygen
under
conditions.
cells.
67
1.3
Xylem:
structure
Xylem
Learning outcomes
tissue
plants.
On
completion
should

be
state
able
that
of
state
water
that
and
in
and
the
xylem
consisting
section,
of

roots,
explain
xylem
roles
of
a
xylem
xylem
stems
how
ions

transport

support.
tubes
differentiate
wall
and
and
is
also
lose
in
sections
leaves
structure
related
and
to
of
their
support.
Also
a
in
bres
provide
two
the
roles
plumbing
in
for
plants:
ions
from
from
cell
end
specialised
cells
meristematic
contents.
walls
than
and
have
resist
xylem
the
so
they
ow
of
compound
Xylem
The
tissue
this
to
cells
They
form
–
xylem
to
gain
become
a
water
.
that
a
dead,
continuous
The
gives
tracheids
the
supports
tissue
pulled
is
in
by
vascular
walls
the
cellulose
in
centre
wind
bundles
vessel
thick
elements ,
cellulose
empty
cells.
column
are
walls
in
the
conduct
role
various
of
roots
blowing
of
cell
They
without
impregnated
any
strength
with
and
provide
aerial
provide
plants
impregnated
water
xylem.
and
non-conducting
Xylem
tissue
is
ways:
to
the
stem
(non-woody)
walls
that
structural
plants
the
the
herbaceous
Thick
are
contribute
and
keep
thinner
to
complex
that
strong
support
parts
back
for
and
‘strengthening
plants
forth.
rods’
to
help
upright.
with
lignin
resist
the
forces
of
xylem
(pulling)
and
compression
(squashing)
when
stems
blow
about
perforated
the
wind.
walls.

Woody
tissue
plants,
as
support
S tudy
and
leaves.
low
power
under
they
the
such
grow;
canopy
as
trees,
this
of
shrubs
provides
branches
and
the
and
lianas,
bulk
to
a
continually
trunk
to
add
enable
xylem
it
to
leaves.
foc us
carefully
microscope
the
provide
waterproong.
in
then
and
made
their
their
walls
lignin,
foc us
elements
are
lose
tension
Look
that
that
vessels, bres

cross
water
which

vessel
of
These
when
are
vessels
cells
are

Tracheids
of
cells
transport
S tudy
xylem
‘tubes’
tissue
tissue
the
vessels
in
are
long
xylem
is
parenchyma
recognise
‘tubes’
of
you
cross

The
consists
to:
transported

this
and function
at
some
slides
Look
to
of
at
the
power
cross-sections
stems
them rst
locate
high
prepared
roots,
of
under
xylem
to
and
identify
xylem
vessels.
Figure 1.3.1
The vascular tissue has been
Figure 1.3.2
dissected out from the rest of the tissues in
Xylem vessels with spiral,
ring-like and net-like wall thickening
a celery petiole
These
photographs
provide
the
evidence
that
water
travels
in
the
xylem
vessels.
Figure
a
1.3.3
root.
thick
Y
ou
cell
prepared
lignin.
Y
ou
shows
should
walls
for
may
be
and
the
Their
some
be
xylem
able
are
to
wide
microscope
cell
walls
asked
to
are
make
vessels
recognise
cells
they
often
with
are
from
the
no
drawings
cell
often
stained
of
the
xylem
central
contents.
stained
red
in
xylem
to
these
Xylem vessels in cross-
section. It is these vessels that are stained

Use

Fill
a
sharp
pencil,
e.g.
HB,
and
never
use
a
pen.
when dyes are used to follow the pathway
taken by water (× 50).
68
at
least
half
the
space
with
your
drawing.
as
In
they
tissue
the
cells
with
sections.
If
of
have
sections
locate
vessels.
advice:
Figure 1.3.3
vascular
vessels
so,
follow
this
Module

Choose

Draw

Look
three
or
four
xylem
vessels
to
2
Biosystems
draw.
S tudy
around
the
carefully
inside
at
the
of
one
of
these.
thickness
of
the
cell
It
wall.
seems
xylem

Make
some
faint
dots
on
the
paper
to
indicate
where
to
draw
of
the
continuous

Draw
in
xylem
adjacent
xylem
vessels
and
then
draw
these
with
are
are
lamellae,
joined
which
is
where
the
cell
walls
of
Draw
the
and
the
and
wide
insides
or
four
you
of
will
cells
complete

If
asked
to
label

If
asked
to
add
leave
adjacent
these
xylem
your
to
both
say
thin
that
and
enough
so
that
wide.
there
contact
cellulose
between
is
wall for
water
enough
to
adhesion
allow
large
together
.
to
the
three
or
four
that
you
cells
vessels
drawing,
annotations,
in
unnished
your
use
write
so
that
you
have
of
water
to ow
easily from
are
roots
drawing;
are
adjacent
volumes

thin
sufcient
middle
vessels
contradictory
vessels
clear
,
lines.
the
foc us
the
They
inside
maintenance
to
leaves.
three
drawing.
lines
your
drawn
notes
with
(as
a
well
pencil
as
and
your
S tudy
ruler
.
labels)
foc us
in
Calculate
the
mean
width
of
the
pencil.
xylem
vessels
compare
Adaptations of
xylem vessels
Features

that
Xylem
allow
vessel
flow
of
elements
water
are
throughout
arranged
in
with
mesophyll
question
the
extend
from
roots
to
Cellulose
walls
are
the
cell.
1.3.3
width
See
of
and
a
palisade
Summary
plant:
columns,
forming
‘tubes’
that
give
a
low
resistance
leaves.
to

Figure
6.
Features
that
in
hydrophilic
so
water
molecules
adhere
the
flow
of
water
in
the
xylem
to
vessels:
them

and
Xylem
support
vessels
the
are
columns
thin
enough
of
to
water
.
support
columns
of

wide

no
lumen,
up
cell
contents
membranes,
Features
that
resist

–
no
cytoplasm
or
nucleus
compression:
empty

0.7 mm
tension
dead,
and
to
water
.
thick
walls
walls
of
cellulose
impregnated

no
cells
end
xylem
walls
vessel
separating
the
elements
with

lignin.
xylem
thickened
vessels
are
continuous
columns.
lignified
Feature
of
xylem
leaves,

that
allows
vessels
stems
rings
or
in
and
stretching
Feature
of
that
of
xylem
pits
wall

allows
of
lateral
water
(in
and
out
of
vessels):
pits
allow
xylem
that
movement
in
small
Figure 1.3.4
stretching
wall
growing
roots:
spirals
thickening
cell
the
cell
regions
walls;
of
thin
these
are
cellulose
The adaptive features of
vessels
cell
wall,
which
allow
easy
xylem vessels
so
they
plants
do
not
grow
break
as
diffusion
longer
.
from
of
one
water
xylem
and
vessel
ions
to
another
.
Summary q uestions
1
Make
the
a
drawing
different
of
a
cross-section
tissues.
Indicate
the
of
a
root
position
to
of
show
4
the
Explain
in
a
how
xylem
transport,
and
vessels
b
are
adapted for
their
roles
support.
xylem.
5
2
Find
colour
make
images
of
xylem
drawings following
vessels
the
advice
in TS
and
given
in
LS
and
Make
a
table
element
to
with
a
compare
palisade
a
mature
xylem
mesophyll
vessel
cell.
this
6
a
Calculate
the
complete
xylem
actual
Calculate
the
width
of
each
of
the
three
section.
3
Make
a
diagram
of
a
longitudinal
section
of
a
composed
thickening.
(See
of
three
Figure
vessel
elements
visible
in
Figure
1.3.3.
xylem
b
vessel
vessels
with
mean
width
of
the
vessels.
spiral
1.3.2.)
69
1.4
Transpiration
Learning outcomes
Pathway of
W
ater
On
completion
of
this
section,
moves

be
dene
able
the
terms
transpiration,
transpiration pull
explain
how

in
ow.
in
the
the
distinguish
is
and
into
cohesion–tension
the
movement
transpiration
between
is
of
stream
cohesion
W
ater
the
The
cells
of
plant
through
as
of
the
the
that
is
and
are
stem
the
to
the
pathway
leaves.
with
Most
least
of
this
resistance
directly
from
the
as
the
absorbed
reason
for
within
water
by
this
lms
fully
leaves
diffuses
through
water
leaves
vessels
passing
and
into
then
the
plants
is
through
passes
that
cell
cytoplasm
of
through
stomata
are
surfaces
of
walls
cells.
A
stomata
open
to
photosynthesis.
surfaces
moist
moves
evaporates
water
for
xylem
without
The
dioxide
exchange
which
through
leaves
atmosphere.
gas
cells,
cell
in
are
walls
cell
saturated
the
into
them
from
walls.
with
from
the
This
water
the
the
xylem.
makes
vapour
.
of
W
ater
the
If
mesophyll
interior
air
spaces
the
adhesion
explain
how
root
contributes
to
outside
movement
will
diffuse
in
the
the
saturated
through
the
then
there
stomata.
is
a
This
gradient,
loss
of
so
water
water
by
and
diffusion
is
transpiration
xylem
T
ranspiration
explain
less
out
of
evaporation
water
is
pressure
vapour

roots
apoplast
travels
carbon
atmosphere

the
proportion
throughout
and
in
mesophyll
absorb
responsible for
water
to
large
capillarity

the
a
to:
transpiration stream, cohesion–
tension,
from
in
you
movement
should
water
role
of
stomata
leads
to
the
loss
of
large
volumes
of
water
,
which
means
in
that
plants
must
always
absorb
large
volumes.
This
is
one
reason
why
transpiration.
they
need
large
such
volumes
consequence
soil
cytoplasm
root
hair
water
of
cell
cell
wall
hair
of
However
,
there

is
symplast
cell
There
a
W
ater
is
pathway
cells
are
pathway
cells

W
ater
through

cells
pathway through
through
stem
xylem vessels
and
symplast
into
pathway

is
of
cells
needed
cells
made
are
needed
are
involved
mesophyll
of
mesophyll
vapour
in
air
of
water
the
such
since
it
is
a
in
atmosphere.
transpiration:
to
stream
of
water
up
the
xylem,
cells.
material
for
photosynthesis,
for
maintaining
vapour
as
a
solvent
phloem
in
a
cells.
transport
medium
for
the
leaves.
a
variety
the
of
functions
opening
magnesium
of
as
water
and
ions
helps
to
inside
closing
for
of
making
keep
plants
cells,
guard
e.g.
potassium
cells;
chlorophyll.
slightly
cooler
plant
the
than
pull
vapour
cells
movement
energy
T
ransport
plant
for
in
is
from
the
aerial
surfaces
of
a
is
main
driver
this
the
through
–
the
xylem
the
energy
by
plant.
to
The
plant
evaporate
transpiration
pull
does
water
is
a
not
comes
passive
need
from
to
provide
the
process
as
Sun.
far
as
concerned.
spaces
loss
of
water
vapour
from
the
cell
surfaces
causes
the
water
mesophyll
Cellulose
through
surrounding
stomata
to
atmosphere
imagine
This
air
is
a
to
is
shrink
away
hydrophilic
meniscus
attraction
of
capillarity
of
to
this
the
cell
attracts
water
water
and
from
and
a
surfaces
water
contracting
surface
sets
up
a
by
and
where
deeper
hydrogen
is
in
pressure
the
cell
bonding.
becoming
water
negative
into
more
low
plant to the atmosphere
This
exerts
apoplast
all
a
pulling
the
way
action
to
the
on
water
xylem
in
into
the
the
leaf.
cell
and
can
concave.
contact
(as
wall.
Y
ou
with
as
through
the
–30 MPa).
The pathway taken by water
as it moves from the soil, through the
70
with
evil’
surface
of
temperatures.
water
molecules
Figure 1.4.1
‘necessary
exchange
loss
cells
The
within
in
in
need
Transpiration
the
water
a
This
between
any
water
raw
the
for
evaporation
ambient
of
walls
to
systems.
be
gas
transpiration
ions
a
and
in
ions
Loss
cell
and
as
Ions
The
leaves
apoplast
through
mesophyll
advantages
water
chloroplasts
pathway
to
extensive
stomata)
root
between
cortical
endodermal
root
considered
an
continuous
assimilates
from
is
(through
needed
turgidity
apoplast
water
having
extensive
apoplast
through
symplast
and/or
root
delivering
cortical
of
of
communication

pathway
deep
the
Module
This
–
pulling
the
result
evaporation
the
action
of
of
cohesive
mechanism
is
due
hydrogen
water
,
forces
that
to
forces
bonding.
capillarity
between
results
in
of
cohesion
The
in
water
‘pull’
the
cell
walls
molecules
transpiration
between
from
is
the
of
water
leaves
the
molecules
driven
mesophyll
2
by
cells
Biosystems
maintenance
Link
the
See Question
and
cohesion–tension
how
pull
rates
of
8
on
page
absorption
transpiration
change
81
to
see
and
over
a
24-hour
period.
Not
only
walls
of
do
water
xylem
maintaining
described
a
molecules
vessels
ow
each
of
by
of
water
them
‘stick’
together
adhesion.
as
in
the
having
This
is
narrow
a
wide
but
they
also
obviously
xylem
lumen,
vessels.
they
‘stick’
to
important
are
Although
not
so
the
in
we
wide
that
S tudy
the
force
of
attraction
the
columns
of
between
water
.
This
is
water
and
important
cellulose
in
cannot
drawing
help
water
across
the
Place
small
spaces
in
the
cell
walls
between
xylem
and
other
a
piece
tension
in
xylem
vessels
is
very
high
and
may
be
–30
This
tension,
generated
by
transpiration,
is
sufcient
water
in
xylem
vessels
to
great
heights.
The
will
tallest
see
trees
115
metres
high.
This
may
be
the
limit
to
water
movement
above
pull.
stomata,
Certainly
low
internal
leaves
at
the
tops
concentrations
of
of
giant
carbon
redwoods
dioxide,
and
low
growth
rates.
This
tension
a
tends
of
very
water.
to
pull
water
rise
up
the
the
is
meniscus
capillarity,
in
the
but
in
movement
it
in
is
xylem
have
low
rates
as
they
do
not
have
menisci.
of
They
photosynthesis
the
involved
vessels
fewer
with
beaker
by
not
transpiration
a
are
beaker. This
about
tubing
into
to
tube
transport
bore
atmospheres
You
(–3.04 MPa).
of
tissues.
narrow
The
foc us
maintain
have
continuous
columns
of
xylem
water.
vessels
inwards,
which
is
why
they
need
strengthening
against
inward
collapse.
Did you know?
Root
The
pressure
continuous
movement
of
somewhere,
a
very
far
.
It
great
is
absorption
water
so
it
force
into
moves
and
important
water
xylem
upwards
does
in
of
the
not
some
from
in
the
the
into
the
account
herbaceous
soil
root.
stem.
for
the
by
This
osmosis
water
This
root
movement
(non-woody)
leads
has
to
to
plants
water
that
is
not
very
are
Sometimes dissolved
of
pressure
of
a
go
solution to form
xylem.
It
is
when this
tall.
Often
absorption
of
water
at
night
occurs
at
a
faster
rate
Root
pressure
causes
the
water
to
move
into
the
happens. Gas
columns of
–
a
it
is
exuded
as
the
asked
top’
by
‘pulling’
explain
7
that
on
how
water
water
draws
page
However,
loss
up
is
transported
from
in
mesophyll
columns
of
water
the
cells
from
xylem,
that
the
begin
acts
roots.
as
‘at
into others through
1
controlled
Explain
are
dependent
on
the
size
of
the
stomatal
by
inside
the
humidity,
leaves.
plant
night
this
when
and
open
rhythm
cells
then
They
guard
cells.
pump
is
in
absorbed
temperature
are
water
also
is
during
in
the
reversed.
These
day,
cells
are
sensitive
carbon
the
Stomata
the
there
cell
lower
dioxide
signalling
although
to
from
to
to
supply.
open,
ions
osmosis
and
sensitive
short
T
o
potassium
by
to
the
statement:
are
surface
the
cells’
apoplast
so
to
some
be
released
closed
species
membranes
water
the
swell.
The
cellulose
microbrils
in
the
cell
by
2
the
of
any
wider
.
As
each
guard
cell
enlarges
it
become
prevent
the
lengthens,
the
opening
other
the
pore
guard
cell
between
at
either
them.
T
o
end;
both
close,
cells
bow
potassium
cells
so
that
they
become
accid.
Energy
for
pumping
the
chloroplasts,
which
generate
lots
of
pressure
pull;
and
and
capillarity
and
Explain
how
hydrogen
bonding
cells
capillarity
are
involved
in
the
pushing
and
ions
of
water
in
plants.
so
water
leave
Transpiration
involves
the
loss
comes
to
from
the
cohesion
cohesion–tension.
4
the
of
photosynthesis’.
turgid
outwards
ions
root
transpiration
is
transport
against
consequence
between
pairs:
adhesion;
guard
W
ater
Distinguish
and
becoming
inevitable
exchange for
following
at
where
potential.
cells
walls
plants
concentrations
chemicals
tend
in owering
light
3
and
pits.
pores,
gas
intensity,
can ow
xylem vessels
Summary q uestions
81.)
transpiration
is
as
the
is
which
xylem
(See
cells
of
water
blocked
‘Transpiration
Rates
in
known
droplets.
describing
force
Question
Guard
to
bubbles
water
phenomenon
laterally out of
When
in the
‘clicks’
leaves
cavitation.
where
bubbles
hear
than
vessels
transpiration.
gas
possible to
come out
not
break the
very
gases
the
atmosphere
of
very
large
A
TP
.
quantities
of
advantages
water.
of
State
the
transpiration
to
plants.
71
1.5
Measuring
A
Learning outcomes
On
completion
should
be
able
of
this
transpiration
section,
simple
state
that
measure

explain
to
into
test-tubes
The
volume
measure
or
asks
water
of
uptake
water
as
by
you
plants
can
see
is
in
to
place
Figure
cut
shoots
1.5.1.
you
of
water
absorbed
by
the
shoot
can
be
measured
by
marking
to:
the

way
rates
a
potometer
water
how
a
uptake
is
used
by
potometer
to
plants
can
levels
lost.
The
of
water
on
Alternatively,
rate
of
the
the
uptake
is
test-tube
shoot
and
could
calculated
be
nding
placed
out
into
how
a
much
has
measuring
been
cylinder
.
as:
3
be
volume
of
water
absorbed
in
cm
___________________________________________________
rate
used
loss
to
in
measure
rates
of
explain
effects
on
how
of
rates
of
water
=
water
time
to
investigate
the
environmental factors
of
transpiration.
and
Often
can
the
also
rates
be
of
used
water
not
cells
by
are
W
ater
the
with
partially
into
that
test-tubes
shows
method
whether
transpiration
only
placed
determine
this
know
are
turgid.
1.5.1
Did you know?
do
shoots
to
Potometers
limitation
we
atmosphere
if
compare
uptake
taken
in
are
how
how
water
goes
into
placed
much
this
all
or
the
cell
a
water
be
that
it
cells
has
some
when
cut
absorb
vacuoles
balance
is
only
water
whether
turgid
on
could
is
the
actually
has
from
water
will
and
measures
been
lost
been
a
and
to
the
different
plants,
to
different
The
to
some
use for
plant
might
problem
methods
fully
be
So
possible
Figure
is
time
with
that
to
it
these
takes
a
obtain
those
The
volumes
of
conditions.
species
that
absorbed
over
the
you
short
could
cells.
the
apparatus.
atmosphere.
water
Suggest
the
by
when
become
it
results.
adapted
so
done.
uptake
especially
uptake
the
absorbed
in
weighed,
lost
water
to
plant,
remain
long
of
hours
transpiration
The

of
term
are
very
small,
this.
so
potometers
Figure
1.5.2
Shoots
are
capillary
possible
that
so
to
it
measure
of
of
is
the
tiny
water
period
in
used.
attached
to
volumes
rubber
are
tubing
absorption
short
like
of
over
a
time.
tubing
three-way
tap
Figure 1.5.1
This apparatus
measures the volume of water
capillary
absorbed by the shoot and the
tube
mass of water transpired to the
top
of
scale
atmosphere
S tudy
air/water
bottom
of
foc us
scale
Measurements
of
transpiration
and
water
uptake
by
crop
plants, forest
trees
meniscus
and
beaker
of
natural
potometers.
Parts
measure
increase
not
plants
involve
can
be
taking
enclosed
cuttings
in
and
placing
transparent
them
chambers
into
the
using
in
humidity;
pulses
of
heat
the
and
movement
of
thermocouples
water
to
in
xylem
to
detect
their
can
be
passing.
A simple potometer that can
be used to measure water uptake over short
periods of time. It can be made even simpler
by omitting the three-way tap and syringe.
72
of
do
water
determined
Figure 1.5.2
vegetation
It
is
also
involved
possible
in
to
use
remote
transpiration.
sensing
devices
to
detect
the
energy
changes
Module
When
need

setting
to
Cut
be
up
this
sort
of
potometer
there
are
various
precautions
the
leafy
S tudy
twig
under
water
so
that
air
does
not
get
into
the
block
Make
an
oblique
foc us
of
transpiration
are
inuenced
them.
by

maintenance
xylem
Rates
and
Biosystems
that
taken:
vessels
2
cut
to
increase
the
surface
through
which
water
the
degree
of
opening
of
stomata,
is
the
steepness
of
the
water
potential
absorbed.
gradient

Use
a

Place
syringe
the
leafy
attached)
avoid

Use

Leave
a
the
moves
the
air
to
of
has
meniscus
to
back
tubing
water
.
into
(with
Push
the
with
the
water
.
rubber
twig
rubber
or
or
into
leaves
plastic
the
plastic
tubing
quantity
tubing
rubber
tubing
that
support
for
a
set
to
the
while
become
put
of
potometer
and
until
air
the
constant.
conditions
more
the
between
and
can
to
will
the
of
water
bottom
will
rate
The
be
at
the
the
the
leafy
drawn
which
plant
before
into
of
with
into
the
results
are
capillary
air
water
suggest
inside
vapour
hold. Try Question
and
how
4
that
on
results
the
the
page
these factors
the
the
and
air
80
are
recorded.
twig.
the
capillary
meniscus
should
the
atmosphere,
responsible for
readings
new
reservoir
tubing
water
.
to
take
any
the
of
bubbles
stand
not
capillary
and
bowl
apparatus
Do
adjust
the
twig
a
upwards
syringe
ll
absorption
clamp
tubing.
to
into
getting
prevent
to
be
given
taken.
tubing
Use
and
Summary q uestions
time
1
the
Explain
push
Figure
tube.
water
why
1.5.2
the
potometer
measures
uptake
and
not
in
rates
of
rates
of
transpiration.
The
be
distance
recorded
travelled
and
transpiration
and
dividing
is
by
used
by
to
the
determined
the
meniscus
calculate
time
by
the
over
rate
of
calculating
taken
for
the
certain
water
the
periods
uptake.
volume
meniscus
to
of
of
time
The
water
move
the
can
rate
of
2
Write
absorbed
set
up
a
is
another
design
of
a
potometer
in
Question
6
on
page
potometer
of
3
factors
fairly
on
are
the
easily
presence
used
rate
using

light

air
and
of
Discuss
water
the
of
to
determine
the
transpiration.
simple
effect
These
of
different
factors
can
of
environmental
be
absence
water
of
light
for
investigated
plants
in
Explain why
and
their
it
temperature
humidity

intensity
leafy
twig.
of
rates
transpiration
natural
habitat.
is
important to
and
light
keep
intensity
investigating the
temperature.

speed on water
movement
table
shows
ways
in
which
these
ve
Environmental factor
Design of
presence

place
a

place
another

place
a

place
other

measure

place
a

place
another
air
the
the
potometers:
uptake
and
absence
light
light
a
determining
uptake
effect of wind
of
by
limitations
constant when
The
on
affect transpiration
4

investigate
different factors
potometers for
Potometers
to
setting
81.
uptake
Factors that
instructions for
distance.
effect
There
out
intensity
movement
potometer
temperature
the
light
the fan

adjust
the
set
up
in
leafy twig.
investigated.
or
drying
potometers
in
the
agent
at
dark
is
well
room
netting
with
room
hairdryer
of
that
lit
or
in
a
box
Sun
movement
humidity
a
a
a
under
potometer
air
in
intensity
potometer
using
in full
potometers
adjust

be
somewhere
potometer
potometer

and
could
a
investigation
continuous
humidity
factors
by
a
with
still
identical
over
to
air
like
the
give
give
different
degrees
of
shading
meter
air
and
no
conditions
draughts
except
use
a fan
or
hairdryer
to
create
in
plastic
plant
different
around
calcium
different
to
light
times
the
wind
speeds
potometer
chloride
during
or
the
by
silica
day
enclosing
gel
and
to
give
record
it
dry
the
a
clear
bag
air
temperature
73
2
Biosystems
2.
1
Phloem
maintenance
The
Learning outcomes
movement
translocation ,
On
completion
should
be
able
of
this
section,
you
transports
and

state
that
movement
of

is
state
which
Sucrose
transported
sap
simply
and
are
amino
the
source
means
which
across
from
leaf
from
to
sink
one
place
compounds
acids
into
are
the
is
known
to
another
.
produced
produced
nearest
in
ne
as
by
the
Phloem
plant’s
mesophyll
endings
of
cells
the
phloem
phloem
sap
phloem
assimilates,
metabolism.
to:
of
sieve
tubes.
translocation
that
sucrose
assimilates
are
and
Phloem
tissue
phloem
sap
is
always
found
close
to
xylem
tissue.
The
composition
of
other
transported
is
very
different
to
that
of
xylem
sap
as
it
contains
in
assimilates.
phloem
sap
In

state
that
sieve
tubes
plant
where
composed
of
sieve
tube
recognise
phloem
substances
tissue
microscope
in
Section
slides
in
draw
and
label
companion
sieve
tubes
and
1,
the
in
the
water
is
loaded
leaves.
It
will
xylem
is
in
potato
again,
new
back
to
information
pages
on
the
8–13 for
products
sink
are
unloaded
used
from
to
describe
transport
the
places
tissue.
As
we
into
also
xylem
be
vessels
unloaded
in
in
the
roots
owers,
and
fruits
one
direction
from
the
sources
and
(roots)
seeds.
to
stage
mature,
stem
these
can
be
seeds
tubers.
over
stores
and
are
and
quite
different
Rhizomes
very
dry
leaves
sources
or
and
cold
sinks
not
in
store
and
yet
assimilates
are
such
sinks
rhizomes
in
When
amino
the
to
of
acids
roots,
ginger
form
growth
are
photosynthesising.
phloem
are
transported
as
energy
periods.
sucrose
are
since
and
organs,
tubers
very
and
that
and
leaves
storage
mobilised
young
both
is
photosynthesising
fruits,
survival
shoots
transport
of
begins
sent
to
Some
transport.
the
The
light-independent
for
organs
of
by
Phloem
owers,
starch
Link
etc.)
produced
stems,
cells.
and
Look
and
and
photographs
(leaves,

source
into
and
T
ransport
in
terms
loaded
in
unloaded
prepared
the
are
elements
saw

transport,
are
conducting
cells
in
phloem
form
sieve
tubes,
which
are
made
from
of
specialised
cells
known
as
sieve
tube
elements.
These
cells
differentiate
photosynthesis.
from
meristematic
different
sizes.
are
companion
the
cytoplasm,
cytoplasm
a
that
larger
divide
cells
Sieve
tube
companion
many
are
longitudinally
sieve
tube
elements
cells
mitochondria
lose
retain
to
to
form
elements
their
their
provide
nuclei
nuclei
two
and
and
and
cells
the
of
smaller
much
have
a
of
dense
energy.
–
across
sieve
plate
companion
Figure 2.1.1
cells
cells.
but
with
sieve tube
sectioned
The
cell
A cross section of phloem
tissue from a squash plant, Cucurbita
pepo (× 60)
sieve tubes
–
Figure 2.1.2
A drawing made
sectioned
from phloem tissue similar to that
between
sieve
in Figure 2.1.1 (× 100)
plates
Figure
stem.
thick
a
2.1.1
Y
ou
cell
shows
should
walls
companion
cross-section.
Figure
74
2.1.3.
and
cell.
Y
ou
some
be
able
are
to
see
tubes
the
adjacent
sections
also
sieve
recognise
usually
Some
can
phloem
have
sieve
from
sieve
to
a
sieve
plates
much
plates
in
a
vascular
tubes
the
as
they
thinner
as
you
bundle
do
cell,
can
not
which
see
longitudinal
in
in
a
have
is
the
section
in
Module
Sieve
tubes
plates
are
within
them.
companion
as
sucrose,
When
tube
the
cells,
are
a
elements
of
are
drawing
Sieve
tissue
tube
is
68.
are
thought
hydrostatic
and
to
prevent
pressures
between
sinks
and
tissue,
Do
an
not
where
follow
shade
annotation
cytoplasm
and
cytoplasm
tube
sieve
that
sieve
develop
tubes
and
assimilates,
such
is
that
more
the
to
to
same
show
indicate
there
is
heavily
advice
the
as
for
contents
that
dense
the
of
sieve
cytoplasm
stained
than
in
the
for
sieve tubes
the
transport
of
phloem
sap.
have:
Figure 2.1.3

cell
membranes
maintenance
elements.
phloem
adapted
elements
sources
phloem
label
The
sieve
that
high
plasmodesmata
in
page
some
cells.
Adaptations of
Phloem
a
walls
the
Biosystems
unloaded.
of
on
use
have
the
of
many
and
tissue
companion
end
result
especially
Instead
contents
a
loaded
xylem
cells.
as
There
making
drawing
the
perforated
expanding
2
that
retain
sucrose
and
other
assimilates
within
A longitudinal section of
phloem tissue from Cucurbita
the
pepo
showing sieve tubes with sieve plates
cells
(× 40)

little
of

cell
contents
phloem
sieve
any
reduce
resistance
to
ow
sap
plates
resist
to
to
hold
internal
sieve
tubes
together
and
pressure
mitochondrion
sieve

sieve
pores
to
allow
ease
of
ow
between
sieve
plate
tube
elements.
nucleus
Companion

many
cells
mitochondria
solutions

many
have:
into
the
to
provide
sieve
plasmodesmata
energy
to
companion
move
cell
tubes
to
allow
easy
movement
of
rough
phloem
sap
into
and
out
of
the
sieve
tubes
endoplasmic

pump
cell
proteins
surface
and
co -transporter
membranes
for
proteins
absorption
of
in
reticulum
the
sucrose
Golgi
from

the
some
cells
apoplast
pathway
plasmodesmata
for
transport
pathway
(in
of
some
from
shared
sucrose
mesophyll
with
via
sieve tube
mesophyll
the
body
cells
element
symplast
species).
Figure 2.1.4
This drawing was made from transmission electron
micrographs. It shows a sieve tube and a companion cell in
longitudinal section (× 300).
Summary q uestions
1
Indicate
of
the
position
cross-sections
for
Summary
of
of
the
root,
question
6
phloem
stem
in
1.
1
and
of
on
the
leaf
this
drawings
that
you
3
made
Make
tissue
module.
three
light
2
Find
colour
companion
following
page
images
cells
the
of
in TS
advice
phloem
and
given
LS
in
sieve
and
this
tubes
make
diagram
of
composed
companion
a
of
longitudinal
three
cells
as
sieve
they
section
tube
of
phloem
elements
would
be
seen
and
in
the
microscope.
and
drawings
section
a
and
4
on
Explain
how
phloem
tissue
is
adapted for
its
role
in
transport.
68.
5
Calculate
the
mean
C. pepo shown
in
diameter
Figure
of
the
sieve
tubes
of
2.
1.
1.
75
2.2
Translocation
Phloem
Learning outcomes
bright
On
completion
should
be
able
of
this
section,
you
it

explain
how
assimilates
is
and
unloaded
in
that
has
from
owers,
pulled
move
in
good
leaves
seeds
upwards
either
conditions
to
roots
and
by
direction
fruits.
for
and
a
plant.
For
photosynthesis,
also
Xylem
transpiration.
in
upwards
sap
the
phloem
from
moves
During
leaves
only
life
example,
of
in
a
sap
to
one
on
a
hot,
moves
growing
direction
plant,
phloem
as
sap
are
may
loaded
day
may
downwards
points,
to:
sap
travel
in
both
directions
through
an
individual
sieve
tube.
When
a
leaf
the
starts
to
grow
,
it
is
not
photosynthesising
but
using
sucrose
imported
from
phloem
other

explain
the
phloem
mechanism
sap
by
which
moves.
leaves
ow
through
There

S tudy
to
provide
photosynthesising,
are
sieve
three
Sucrose
it
and
its
cells
with
becomes
tubes
in
a
the
energy.
net
opposite
main
principles
other
assimilates
Later
,
exporter
with
loaded
when
the
sucrose,
direction
involved
are
of
to
that
at
transport
at
the
leaf
which
the
in
source
is
will
then
start.
the
phloem:
where
there
is
a
foc us
build
Translocation
is
another
example
of

A
up
of
pressure
through
mass ow.

The
gradient
sieve
Sucrose
low
hydrostatic
and
is
tubes
other
hydrostatic
mechanism
pressure.
responsible
from
source
assimilates
for
to
are
movement
of
phloem
sap
sink.
unloaded
at
the
sink,
so
forming
a
pressure.
for
phloem
transport
is
pressure
ow.
Pressure flow
Figure
S tudy
2.2.1
opposite
shows
these
three
processes.
Look
at
the
gure
foc us
while
reading
about
the
processes
of
loading,
pressure
ow
and
unloading.
Loading
and
dependent
you fully
and
on
osmosis.
understand
water
involved
unloading
potential
in
phloem
are
Make
how
sure
1
osmosis
gradients
Mesophyll
Sucrose
are
absorbed
species,
transport.
in
S tudy
for
foc us
2
These
those
proton
in
their
energy
redox
are
mitochondria
chloroplasts.
as
pumps
of
transport
chain
as
in
(see
not
the
11
cell
The
passes
maintain
and
similar
cell
change
cells
from
cells
by
a
it
products
pathway
form
of
is
gradient
converted
of
along
active
plasmodesmata
diffusion
cells
the
apoplast
through
the
have
energy
wall
that
from
the
to
surface
proteins
electron
pages
use
protons
use ATP
the
companion
companion
Companion
These
coupled
the
to
the
sucrose
for
photosynthesis.
cell
from
and
In
as
another
soon
form
of
is
some
mesophyll
sucrose,
into
walls
transport.
cells;
as
it
sugar
transport.
the
these
energy,
transferred from
reactions
to
and
However,
source
similar
into
make
through
sucrose
order
enters
cells
passes
A
TP
in
pump
sucrose
transfer
in
of
spaces.
and
protons
into
cell
the
the
creates
membrane.
cytoplasm
a
gradient
into
for
mitochondria.
cells
on
surface
from
This
companion
and
them
the
protons
chloroplasts
membranes
to
pumps
to
intercellular
those
accept
shape
proton
the
have
co -transporter
external
surface
and
cytoplasm.
and
The
proton
gradient
drives
this
active
transport
of
sucrose
into
the
29).
companion
3
Sucrose
cell,
diffuses
plasmodesmata
4
The
movement
potential
very
far
than
away,
Remember
membrane,
and
The
to
76
to
from
of
so
that
turgor
the
the
the
of
is
into
moves
tube
of
water
pressure
of
to
concentration
cells
phloem
the
sieve
tissues.
by
cells
intact
loss
high
companion
surrounding
sieve
a
adjoining
sucrose
water
which
prevent
maintaining
into
the
absorption
the
so
sieve
tube
into
are
the
surrounded
allow
the
absorption
sucrose.
extensive
tube.
creates
There
osmosis
are
through
of
by
of
a
lower
xylem
sieve
cell
water
vessels
tube
not
cells.
surface
water
by
osmosis
sucrose.
builds
other
up
a
plant
high
hydrostatic
cells.
pressure
similar
Module
5
The
the
be
pressure
pressure
upwards
may
be
the
sink,
enzyme
active
7
The
cells
also
uptake
so
areas
of
cells
sink
of
water
the
Also
in
or
of
sucrose
some
the
is
loaded
sieve
points,
storage
energy
out
as
Some
tissues
is
greater
tube.
owers
This
or
maintenance
than
may
fruits;
or
organs.
neither
required
sucrose
by
will
tubes
Also
it
invertase)
the
takes
sink
the
is
loaded
sieve
be
nor
tubes
unloaded
down
broken
into
absorption
of
the
sieve
it.
also
into
out
decreases
of
using
known
sugars
end
is
Biosystems
as
the
to
stems.
are
moves
sucrose
growing
roots
diffuses
that
other
where
provide
absorbed.
water
the
where
leaves,
towards
(also
by
movement
loss
tubes
at
new
in
for
sucrase
gradient,
The
sink
sucrose
into
are
sieve
mitochondria.
energy
gradient
which
cells
probably
lack
provide
At
the
downwards
unloaded
6
in
the
towards
Companion
latter
in
2
of
its
glucose
sucrose
concentration
down
by
and
is
the
fructose,
passive,
but
place.
tissues
sieve
creates
tubes
hydrostatic
into
a
the
pressure,
so
water
sink
potential
Figure 2.2.2
tissues.
maintaining
a
This transmission electron
micrograph shows a specialised
companion cell – a transfer cell. Notice
pressure
gradient
from
source
to
sink.
The
pressure
gradient
drives
the
ingrowths of the cell wall (× 5000).
movement
of
phloem
Sealing damaged
Damage
to
pressure
drops
pores.
phloem
Plants
response
to
See
the
model
of
this
on
page
79.
sieve tubes
tissue
suddenly
make
sap.
is
callose,
wounding
repaired
within
and
a
sieve
by
plants
tubes,
polysaccharide
this
also
helps
to
very
quickly.
proteins
made
seal
block
from
If
up
the
the
S tudy
β-glucose,
damaged
sieve
foc us
sieve
in
tubes.
Look
then
carefully
answer
Think
about
companion
read
when
at
Figure
Summary
2.2.2
the function
cells
that
6.
of
you
answering
and
question
the
have
just
question.
water
chloroplast
Summary q uestions
1
water
source
in
the
terms
translocation,
assimilates, source,
2
sucrose
Define
Explain
why
parts
sink
of
a
plant
may
made
be
cytoplasm
a
source
year
and
a
at
one
sink
at
time
of
the
another.
Key
3
Transport
in
the
described
as
an
phloem
is
sucrose
active
process.
molecules
4
Explain
why
Explain
the
in
loading
phloem:
starch
this
is
roles
of
sucrose
proton
so.
the following
into
the
pumps,
proton
grain
gradient,
co-transporter
proteins
water
and
5
sink
plasmodesmata.
State
three
transport
ways
in
the
in
which
phloem
differs
water
from
6
Suggest
in
water
Figure 2.2.1
transport
why
Figure
in
the
2.2.2
the
xylem.
transfer
has
many
cell
wall
ingrowths.
Mechanisms involved in translocation. Read carefully the notes on each stage.
77
2.3
Assessing the evidence for phloem transport
This
Learning outcomes
section
which
On
completion
should
be
able
of
this
section,
you
tubes
in
to:
has
so
the
compare
xylem
the
sap
composition
with
phloem
compare
the
structure
with
phloem
analyse
and
transport
in
the
extracts
study
because
have
most
of
investigations
plants
been
bizarre
phloem
sap
is
to
into
used
to
seal
to
use
phloem
transport,
wounds
investigate
the
compare
stylets
with
in
sieve
movement
of
sap-sucking
xylem
sap.
feed
on
phloem
sap
by
inserting
(froghoppers)
insert
their
their
stylets
stylets
into
into
individual
xylem
sieve
vessels
on
xylem
sap.
The
young
stage
of
spittlebugs,
which
are
pests
and
which
they
of
tissue
interpret
evidence for
to
the
techniques
perhaps
obtain
Spittlebugs
tropical

difcult
V
arious
of
xylem
feed
tissue
to
Aphids
sap
of
proved
fast.
some
of
tubes.

about
phloem;
insects

is
the
methods
of
insect,
plants.
or
with
radioactively
a
for
single
be
a
tubes
a
long
phloem
under
exude
have
miniature
continue
sieve
stylets
injected
grasses,
Researchers
leaving
xylem
single
leaf
pasture
themselves.
to
ow
and
time
pressure
for
tube
out.
xylem
to
sieve
it
to
frothy
liquid
through
through
They
total
Phloem
This
continue
stylets
the
been
volumes
element.
with
the
which
have
vessels.
give
tube
a
cut
far
to
excess
that
that
cover
types
of
sample
exudes
in
shows
both
contents
able
sap
of
the
of
the
the
from
of
from
cut
contents
phloem
length
phloem
sap
the
the
of
sap
of
must
owing
for
time.
used
investigate
the
movement
external
the
xylem
stylet
aphid
Ringing
solutes
(also
in
removed,
sieve
known
stems.
as
A
shown
in
The
concentrations
that
were
stem
of
ringed.
an
as
girdling)
complete
Figure
of
unringed
were
were
control
of
to
tissue
to
of
is
2.3.2.
sucrose
Samples
is
ring
determined
also
plant.
taken
The
in
from
results
several
the
are
same
shown
parts
of
a
positions
in
the
stem
on
the
table.
tube
Part of the
aphid
phloem
plant
sap
where
Concentration of
Ringed
stylet
drop
from
oozing
liquid
sieve tube
Figure 2.3.1
units
plant
Unringed
(control)
plant
oozing
anus
a
sucrose/arbitrary
sample taken
in
the
stem
above
the
ring
0.60
0.43
in
the
stem
below
the
ring
0.00
0.41
in
the
roots
0.03
0.30
b
a An aphid feeding on
phloem. Aphids have mouthparts that are
like a hypodermic syringe, which they
insert into individual phloem sieve tube
elements. b Aphid stylet used to collect
Radioactive
tracers
became
available
in
the
middle
of
the
20th
century.
liquid from a sieve tube.
Leaves
were
supplied
with
carbon
dioxide
labelled
with
the
radioisotope
14
carbon-14
C).
(
This
was
done
by
enclosing
14
with
a
leaf
in
a
transparent
bag
14
C
some
labelled
carbon
dioxide
(
CO
).
Radioactivity
was
detected
2
in
up
the
a
rest
of
stem,
well
as
in
the
plant
some
radioactivity
the
roots.
was
hours
later
.
detected
Radioactive
in
sucrose
When
applied
growing
was
tips,
detected
to
a
leaf
owers
inside
halfway
and
fruits
as
phloem
sieve
phloem
is
ringed
tubes
in
leaves,
stems
and
roots.
area
The
most
mass
popular
ow,
with
mechanism
movement
proposed
due
to
for
transport
differences
in
in
the
hydrostatic
pressure
transverse
between
section
of
sources
and
sinks.
This
mechanism
was
modelled
in
1926
by
stem
Ernst
with
Münch
(1876–1946).
explanatory
Figure
2.3.2
shows
a
diagram
of
his
model
notes.
longitudinal
section
Figure 2.3.2
of
stem
S tudy
foc us
A cross-section and a
longitudinal section of a stem to show the
It
is
possible to
see that
aphid
stylets
are
inserted
into
single
sieve tube
elements
procedure of ringing in which the phloem
by taking
is removed from a stem
78
sections of
stems
infected
by
aphids
and observing with
a
microscope.
Module
glass
Cell
A
–
has
membrane
tube
linking
cell
A
to
cell
B
represents
the
2
phloem
permeable
Cell
only
to
water.
with
sucrose.
a
It
It
contains
high
a
solution
concentration
represents
the
leaf
direction
of
of
of
sucrose
flow
of
solution
B
–
has
only
to
with
little
a
membrane
water.
It
permeable
contains
sucrose.
It
a
solution
represents
a
respiring
or
storage
regions
of
the
plant
glass
tube
linking
plant,
A
the
Water
enters
cell
A
by
e.g.
osmosis
two
vessels
represents
the
–
xylem
Water
because
it
has
a
lower
than
leaves
because
it
is
forced
water
out
potential
roots
B
the
due
to
the
high
pressure
water
direction
surrounding
of
water
flow
potential
created
in
A
it
Provided sucrose is continually produced in A (leaf) and continually removed at B (e.g. root), the mass flow of sucrose from A to B continues
Figure 2.3.3
Here
is
a
Münch
Ernst Münch’s model of pressure ow
list
of
the
proposed
most
his
important
discoveries
about
translocation
since
Did you know?
model:
Aphids

The
distance
travelled
by
sucrose
in
the
phloem
is
very
long
–
up
crops
about
100
The
serious
such
as
pests
peppers
of
and
many
beans.
metres.
Not

are
to
speed
at
which
sucrose
travels
in
phloem
is
between
0.05
by
–1
only
do
they
reduce
the
yield
and
removing
assimilates from
the
–1
and
0.25 m h
may
be
as
high
as
1.00 m h
.
Sucrose
diffuses
from
cell
phloem,
they
transfer
disease-
–1
to
cell
at
speeds
of
less
than
.
20 mm h
causing

When
leaves
freezing
and
decrease.
phloem
and
to
stems
low
Adding
are
oxygen
exposed
to
temperatures
concentrations,
respiratory
inhibitors
to
ow
just
rates
phloem
in
organisms
such
as
viruses.
above
phloem
prevents
any
ow
of
sap.
Summary q uestions

The
hydrostatic
pressures

Phloem

Over
tube
of
sap
time,
1000
to
moves
the
changes.
growing,
pressures
but
2000 kPa
in
opposite
direction
Phloem
is
inside
exported
have
is
been
directions
taken
sap
phloem
by
phloem
those
tubes
are
high
–
recorded.
in
transported
from
sieve
1
adjacent
sap
into
leaves
in
phloem
an
new
when
sieve
individual
leaves
mature
as
tubes.
the
differences
sieve
they
Describe
are
of
xylem
of
phloem
1.3
and
and
similarities
and
between the
tissue
and
tissue
the
(see
structure
structure
Sections
2.
1).
photosynthesising.
2

The
concentration
of
sucrose
in
phloem
sap
is
between
10
and
Summarise
between
in
mesophyll
cells
it
is
Companion
cells
have
many
mitochondria;
A
TP
is
present
in
in
higher
concentrations
than
in
other
sap
and
The

Sucrose
pH

The
of
the
contents
of
companion
cells
phloem
of
sap.
Suggest
why
aphids
are
likely
to
cells.
show faster

differences
composition
these
3
cells
the
0.5%.
xylem

the
30%;
is
about
growth
rates
than
8.0.
spittlebugs.
is
loaded
into
phloem
sieve
tubes
but
other
sugars
are
not.
4
cell
surface
membranes
of
companion
cells
have
pump
Explain
as
for
hydrogen
ions
and
co -transporter
proteins
for
sucrose
the
shown
in
the
of
ringing
table
on
the
and
opposite
hydrogen
effect
proteins
page.
ions.
14

The
water
tubes
The
the
potential
gure
mechanism
mechanism
of
observations
loading
at
of
mesophyll
about
ow
transport.
about
source
and
cells
is
about
–1.5 MPa,
for
sieve
5
–2.5 MPa.
pressure
phloem
made
the
is
of
is
when
generally
However
,
phloem.
The
unloading
at
it
accepted
does
pressure
the
by
not
gradient
sink.
The
scientists
explain
is
all
created
companion
as
between
use
energy
source
and
and
both
sink
processes
does
not
are
require
active.
energy,
The
so
nectar
roots
by
and
of
living
intact
and
not
dead
through
case,
answer
to
the
why
are
sieve
xylem,
cell
are
may
protect
membranes
like
walls.
they
be
tubes
they
do
Sieve
there
that
against
vessel
elements
sieve
not
a
offer
xylem
tubes
are
under
lignied?
have
necessary
plates
since
bursting
not
are
This
support
resistance
lignied
high
may
do
are
xylem?
be
sucrose
to
not
due
and
to
ow.
have
pressures.
sieve
that
both
starch
sucrose
grains
in
in
the
plant.
Identify
the
given
this
in
pieces
of
evidence
This
If
this
may
fact
is
that,
ideas
and
that:
be
the
loading
sieve
the
may
case
the
of
sucrose
into
away
tubes
is
an
active
process
The
plates
which
section for
act
why
unlike
b
movement
phloem
Explain
is
of
by
your
C,
became
tube
‘leaking’
them?
sieve
In
in
leaves,
movement
why
in
prevent
vessels
not
the
to
a
in
to
radioisotope,
cells
a
because
the
applied
against
elements
how
incorporated
the
the
6
involved
Explain
solutes
in
the
pressure ow.
answers.
function.
79
2.4
Practice
The
exam-style
uptake
minerals;
Answers to
1
Plants
a
all
exam-style questions
absorb
Explain
mineral
why
potassium,
A
solution
plants
was
was
prepared
of
seedlings
maintained
table. After
a
require
magnesium
concentrations
Some
ions from
with
mineral
were
at
the
week
in
[6]
in
soil
solution,
concentrations
given
of
six
water.
b
which
in
within
the
root
cells
were
Explain,
of
plants
ii
water
are
shown
in
the
and
phloem
terms
the
Dene
ii
Explain
the
of
absorb
moves
i
water
potential,
water from
across
the
the
how:
soil
cortex
[3]
of
the
root
xylem vessels.
the
term
how
[3]
transpiration.
transpiration
movement
of
water
is
in
[2]
responsible for
the
xylem.
[4]
the
Xylem vessels
are
adapted for
the
transport
of
water
determined. The
over
results
in
i
the
4
ions
a
into
as found
this
water
accompanying CD.
3
ions.
of
the
same
concentrations
the
in
phosphate,
sulphate
the
ions
grown
be found on the
soil.
nitrate,
and
transport
transport
can
the
and
questions:
long
distances.
table.
a
Describe
b
Explain
the
structure
of
a
xylem vessel.
[3]
–3
Ion
Concentration/mmol dm
how
transport
Soil
solution
Root
cell
water
1.00
used
uptake
they
0.01
a
of
are
long
potometer
leafy
were
at
to
shoots
different
able
to
adapted for
the
distances.
[4]
measure
of
croton,
the
rate
of
Codiaeum
times
investigate
during
the
the
effect
day
so
that
of
1.00
temperature. The
potassium
1.00
calcium
1.000
table
shows
their
results.
75.00
Experiment
magnesium
over
8.00
variegatum,
phosphate
xylem vessels
water
contents
Students
nitrate
of
0.001
0.
10
Temperature/
Wind
speed
Mean
°C
(setting on
rate of
fan)
movement
0.45
of
gas
bubble/
sulphate
0.25
9.50
–1
mm h
b
With
reference
i
describe
ii
explain
to
the
the
the
suggest
the
2
a
cell
to
explanation for
the function
cells;
in
between
potassium
concentrations
Describe
plant
an
of
each
of
of
case
ions
the
calcium
each
of
relate
the
endodermal
ii
sieve
15
low
2
15
high
22
difference
3
25
low
24
4
25
high
45
5
35
low
64
6
35
high
in
ions.
[2]
the following
the
structure
of
the
cell
element
Using
b
companion
iv
xylem vessel
Explain
the
transport
c
Explain
80
in
how
transport
cell
in
[3]
element.
terms
source
and
[2]
sink
as
applied
plants.
transport
the
the
data
in
the
table,
describe AND
explain
[2]
the
iii
120
[2]
c
tube
12
[2]
its function.
i
1
[3]
difference
concentrations
iii
table:
results
xylem.
the
phloem
students
d
Make
of
the
two
changed
two
on
criticisms
conditions
the
of
rate
the
of
that
the
water
design
of
uptake.
the
differs from
[4]
e
Columns
process
plants
of
[2]
water
known
survive
[6]
students’
investigation.
to
[2]
in
effects
as
in
xylem vessels
cavitation.
when
this
can
Explain
happens.
break,
briey
a
how
[2]
Module
5
a
b
Flowering
plants
they
a
need
Outline
the
Figure
a
of
sucrose
described
2.4.
1
ginger
in
shows
a
by
cell
sucrose
in
a
leaf
as
to
storage
rhizome.
along
the
in
plant
period. The
you
b.
[6]
potometer
set
up
ready
to
take
debrosba
readings.
leafy
shoot
water
well
results
watered
are
of
plant
water
during
a
hot
throughout
shown
water
in
Figure
the
2.4.2.
end
shoot
transpired
24
20
16
water
12
absorbed
8
4
ssam
of
kept
rates
a
28
fo
syringe
cut
was
of
maintenance
32
retaw
reservoir of
the
transpiration
24-hour
the
pathway
investigated
and
day. The
[4]
involved
students
absorption
it
a
Some
ro
6
as
mechanisms
movement
have
taken
mesophyll
8
[3]
deripsnart
the
why
h/g
such
Explain
a
Explain
system.
Biosystems
1–
organ,
multicellular.
pathway
travels from
c
are
transport
2
0
0
4
8
12
16
20
24
tap
time/hours
rubber
calibrated
air/water
capillary
meniscus
Figure 2.4.2
tube
tube
a
Describe
b
Explain
and
the
the
results
shown
changes
transpiration
in
over
in
rates
the
the
of
graph.
water
24-hour
[4]
absorption
period.
[4]
3
scale
calibrated
in
mm
c
Suggest
how
plants
survive
periods
of
severe
Figure 2.4.1
drought.
a
State THREE
precautions
that
should
be
9
when
setting
up
a
potometer
such
as
[3]
taken
the
one
a
Explain
why
all owering
plants
that
live
on
land
in
transpire.
the gure.
b
b
Explain
how
the
potometer
can
be
The
measure
rates
of
water
uptake
effects
the
rates
conditions
Explain
wind
and
how
speed
the
on
effect
the
transpiration
of
rates
can
light
of
be
intensity
water
and
absorption
investigated
using
potometer.
ii
Describe
in
the
diameter
of
stomata
of
transpiration
under
different
of
evaporation
were
investigated
with
[3]
leaves
i
changes
and
transpiration.
c
of
used
on
to
[2]
[3]
[5]
how
potometer
a
the
results
would
be
taken from
processed
to
of
birch
evaporation
rate
of
the
in
table.
the
were
water
under
trees,
Betula pubescens.
determined
loss from
same
pieces
by
of
conditions. The
Rates
measuring
damp
results
of
the
paper
are
shown
the
give
reliable
Rates of
Rates of transpiration
evaporation/
stomatal diameters/mg 25 cm
at different
–2
data for
the volumes
of
water
absorbed
and
–2
transpired.
[2]
mg 25 cm
–1
h
0
7
Silk
cotton
trees,
Ceiba pentandra,
Mucuna sloanei,
transport
from
to
their
roots
the
water
leaves
on
and
over
the
lianas,
great
–1
h
µm
4
µm
6
µm
e.g.
distances
100
0
60
62
200
0
102
120
600
0
330
375
1000
0
590
625
topmost
branches.
a
Describe
the
from
soil
the
pathway
to
the
taken
tops
of
by
silk
water
as
cotton
it
travels
trees
and
lianas.
b
Explain
[4]
how
water
is
transported
to
the
tops
of
i
these
tall
plants.
Suggest
how
conditions
c
Discuss
the
conditions
these
effects
on
plants.
the
the
scientists
changed
the
[5]
of
changes
rate
of
in
water
around
the
birch
leaves
to
give
environmental
movement
different
rates
of
evaporation.
ii
Describe
the
iii
Explain
the
effect
around
the
leaves
Explain
the
effects
[3]
in
results
shown
in
the
table.
[4]
[8]
iv
the
rates
of
of
changing
on
of
rates
of
the
stomatal
transpiration.
conditions
transpiration.
diameter
[3]
on
[3]
81
2
Biosystems
3.
1
Blood
The
Learning outcomes
On
completion
should
be
able
of
this
maintenance
section,

a
closed

a
double
state
that
system
is
a
the
is
closed
body.
there
blood
is
a
At
because
no
blood
point
does
ows
blood
inside
ow
vessels
out
of
in
these
its
journey
vessels
is
a
cut;
and
blood
clots
quickly
to
seal
external
and
except
internal
to
composed
of
red
and
white
describe
the
and
blood
through
the
loss.
The
heart
circulation.
is
There
the
are
pump
three
that
main
keeps
types
the
of
blood
blood
blood
vessel
platelets
limit
tissue
owing

circulation
circulation
that
cells,
is
closed,
wounds
state
mammal
system
system
where

a
mammalian
around
double
of
to:
the
circulatory
system
you
The

circulatory
in
a
closed
system:
arteries,
blood
high
capillaries
and
veins.
plasma
composition
Arteries
transport
delivery
to
at
pressure
from
the
heart,
giving
efcient
of
tissues.
Capillaries
are
where
substances
are
exchanged
between
blood
blood

outline
the formation
of
blood.
and
the
tissue
accommodate
The
one
double
any
uid
volume
circulation
complete
that
of
surrounds
blood
means
circulation
of
and
that
the
cells.
return
blood
body.
V
eins
it
at
ows
There
stretch
low
pressure
through
are
two
to
the
to
the
heart
heart.
twice
in
circuits:
Did you know?

Sir William
who
Harvey
discovered
Pulmonary
(1578–1657),
the
circulation
in
the
body, famously
said
the
a
that
last
to
it
is
‘the rst
die’.
description
Search
of
to
live
Systemic
and
the
that
show
how
one-way ow
published
in
of
blood
The
is
the
heart
in
heart
the
to
the
lungs
pulmonary
in
circulation
through
–
blood
to
the
body ’s
arteries
heart
main
in
vein
to
is
all
pumped
veins
the
by
that
leading
organs,
the
heart
empty
into
the
except
into
into
the
the
the
vena
lungs.
aorta
cava,
Blood
which
of
blood
in
heart.
advantage
of
the
of
body
a
double
at
circulation
different
is
pressures.
that
blood
Blood
ows
is
sent
to
through
different
the
lower
pressure
than
that
in
the
systemic
circulation.
lungs
This
does
damage
the
the
of
rest
there
capillaries
the
body,
would
example
of
mammals.
at
high
of
mass
Blood
found
from
be
A
in
the
the
lungs.
blood
If
would
insufcient
high
pressures
and
is
a
in
tissue.
other
those
blood
so
pressure
there
cells
spun
in
plasma
a
Red
is
in
blood
be
oxygen
in
an
the
owed
supplied
to
at
on
a
from
very
support
the
means
that
aorta
efcient
watery
as
they
pages
uid,
all
–
liquid
chemicals
just
supply
cells
of
as
a
the
low
high
lungs
to
pressure
metabolic
of
blood
is
rate
delivered
oxygen.
in
the
for
is
blood
more
Every
the
blood
the
at
to
is
the
bottom
cells
lifts’
roles
in
of
in
bone
blood.
the
to
of
composed
materials
equivalent
the
white
‘hitch
about
tissue
hard
cells;
If
tube
are
and
white
of
cells
and
blood
(55%
of
blood
volume)
–
plasma
consists
of
water
it:
3
10
cm
•
nutrients,
e.g.
3
5
such
sodium
•
wastes,
•
blood
•
hormones,
as
and
such
as
proteins,
glucose,
chloride
urea
such
and
as
amino
acids,
lipids,
vitamins
ions
carbon
albumen
dioxide
and
antibodies
cm
white
blood
such
cells
as
insulin,
and
Blood cells photographed
red
blood
Figure 3.1.1
glucagon,
platelets
cells
using the high power of a microscope
The composition of blood
is
with
3.1.1.
blood
dissolved
true
use
settle
Figure
part
the
disease).
such
plasma,
the
in
are
144–149
against
shown
plasma
with
cells
substances,
centrifuge,
top
and
(see
defence
The
on
blood
tissues
tissues
extracellular
cartilage.
82
at
not
blood
ow.
(× 1,100)
is
1628.
another
Figure 3.1.2
the
veins.
foc us
movement
vessels
from
the
that
and
S tudy
ows
to
valves
much
he
blood
returns
Harvey’s famous
parts
ensure
then
returns
online for
The
experiment
–
and
of
and
blood
arteries
of

blood
circulation
pulmonary
and
adrenaline.
and
mineral
ions,
Module
Blood
Figure
2
cells
3.1.2
shows
some
microscope.
Figure
3.1.3
blood
cells
shows
a
under
labelled
high
power
drawing
of
of
a
light
some
blood
cells.
phagocyte
The
table
shows
the
features
of
the
cells
shown
in
Figure
3.1.2.
red
Production of
The

blood
bone

populate
The
is
of
cells,
blood
originate
platelets,
in
different
neutrophils
and
places:
monocytes
are
made
in
marrow.
Lymphocytes

cells
blood
components
Red
blood
are
lymph
water
ltered
in
in
also
plasma
the
made
nodes
in
where
is
bone
they
absorbed
kidney,
which
marrow,
divide
from
the
reabsorbs
but
during
early
stomach
most
in
life
they
infections.
of
it
and
intestines.
leaving
a
little
It
Figure 3.1.3
to
The main types of blood
cells that you should be able to recognise
be
lost
as
urine.
Substances,
such
as
ions
(e.g.
sodium
ions),
proteins,
in slides of blood and in photographs
amino
acids,
removed
Type of
red
from
blood
blood
glucose,
it
as
cholesterol
blood
cell
ows
and
fats
through
are
added
capillaries
to
in
plasma
and
tissues.
Features
cell

small

shape:

exible

no
Functions
cell
(7 µm
diameter)
biconcave
disc
can
membrane
nucleus;
no
organelles
RER, Golgi
body)

cytoplasm
is full

contains
the
change
(mitochondria,
more
space
transport
of
shape
and t
easily
through
capillaries
to ll
oxygen
with
and
haemoglobin
carbon
to
dioxide
haemoglobin
enzyme
carbonic
anhydrase
catalyses
reactions
to
help
transport
carbon
dioxide
neutrophil

large

lobed
nucleus

small
nucleus:
polymorphonuclear

mitochondria,
leucocyte

many
(phagocytic
also
known
‘white
lobed
cell)
as
meaning
blood
cell
cell
(10 µm
diameter)
lobed
cytoplasm
ratio
RER, Golgi
body
lysosomes
protein
for
with
lymphocyte

larger

bean-shaped
cell
(12–20 µm

mitochondria,

smaller

large

highly
cell
specic
body
blood
through
synthesis
to
make
digestion
hydrolase
of
bacteria
enzymes
and
pathogens
which are long-lived phagocytic cells
diameter)
cytoplasm
cell
leave
where they become long-lived macrophages,
RER, Golgi
to
cells
these cells are in the blood travelling to tissues,
diameter)
nucleus
(4–6 µm
nucleus
helps
walls
intracellular
other
nucleus’
monocyte
nucleus
capillary
surface
activated
ratio
secrete
receptors
to
become
antibodies;
specialised for
for
be
certain
page
secreting
pathogens;
activated
(see
plasma
many
by
are
cells
which
memory
antibodies
ready
infection
by
and
cells
specic
waiting
those
to
pathogens
144)
Summary q uestions
1
Dene
2
Explain
3
List
4
Explain
the
the
terms
why
closed circulatory system,
blood
is
components
the
a
double circulatory system
tissue.
of
advantages
blood
to
and
state
mammals
of
the
main function
having
a
double
of
each.
circulatory
system.
83
3.2
Blood vessels
Blood
Learning outcomes
of
On
completion
should

be
able
describe
veins
of
section,
blood
explain
body
in
blood
vessels.
There
are
three
main
types
vessel:

artery
structure
of

vein

capillary.
arteries,
capillaries
how
the
structures
three
are
vessels
are
related
lined
by
an
endothelium,
which
is
a
single
layer
of
of
squamous
blood
the
you
All

around
to:
the
and
this
ows
to
cells.
The
endothelium
forms
the
wall
of
capillaries,
but
the
their
walls
of
arteries
and
veins
are
also
composed
of
smooth
muscle
tissue
functions
and

make
labelled
drawings
arteries
of
and
annotated
cross-sections
and
bre-secreting
elastin.
of
The
between
veins.
very
the
triple
There
from
stretched
are
that
make
collagen.
and
recoils
capillaries
in
produce
structure
polypeptides
different
when
cells
helical
it
the
brous
collagen
very
Rather
when
the
of
resistant
like
an
proteins
and
to
elastic
all
collagen
the
stretching.
band,
and
hydrogen
it
bonds
Elastin
is
elongates
released.
walls
of
arteries
and
veins,
supplying
oxygen
Link
and
far
Revise
the
structure
of
nutrients
away
from
of
Module
1
muscle
the
blood
cells
in
and
the
bre-secreting
middle
of
these
cells.
These
vessels
to
be
cells
are
supplied
too
by
collagen from
diffusion,
1.8
to
in Unit
and
in
most
veins
and
some
arteries
the
blood
transported
is
1.
deoxygenated.
The
S tudy
Smooth
foc us
muscle
often
table
describes
the
functions
Blood vessel
Function
artery

carries
of
these
blood owing
blood
vessels.
away from
the
heart
at
high
causes
pressure
problems. As
would
be
vessels.
its
name
good for
suggests
lining
Endothelium,
the
which
it

stretches

delivers
is
not
lining
tissue, forms
of
the
blood
the
recoils
to
maintain
the
blood
pressure
blood
to
organs
at
a
pressure
slightly
less
than
a
when
muscle
and
blood
it
left
the
heart
smooth
vessels.
vein

carries

expands
blood owing
to
take
towards
increasing
the
heart
volumes
of
at
low
blood,
pressure
e.g.
during
exercise

as
by
capillary

blood
carries
allows
water
Figure 3.2.1
is
low,
valves
at
blood owing
pressure

pressure
semi-lunar
and
the
low
of
blood
is
prevented
between
arteries
and
veins
at
low
speed
exchange
between
backow
intervals
of
blood
respiratory
and
gases,
solutes
and
tissue uid
Cross-sections of an artery
and vein (× 10)
Figure 3.2.2
This electron micrograph
of a cross section of a capillary shows
that a red blood cell is about the same
diameter as that of the blood vessel
(× 4250)
84
Module
Blood vessel
Structural features
Relationship
2
between
structure
and
function
endothelium
artery
thick
smooth inner lining to reduce chances of
layer of
high
muscle
ratio
of
wall
thickness:
turbulent ow, which promotes blood clotting
and
diameter
elastic fibres
of
lumen
elastic tissue stretches as blood is pumped into
thick
layer
of
elastic
tissue
thick
layer
of
smooth
thick
outer
an artery; it recoils to maintain pressure
muscle
smooth muscle maintains a tension in the
artery to help maintain blood pressure
thick
small
space
outer
through
layer
of
collagen bres
collagen bres give strength to prevent
which
layer
bursting
blood flows
vein
two
endothelium
outer
layers
low
muscle
and
are
elastic
ratio
smooth
wall
thickness:
lumen
lining
diameter
of
(see
vein
above)
increases
to
take
more
blood
diameter
fibres
thinner
little
than
of
elastic
tissue
and
smooth
blood
pressure
is
low
so
less
of
these
are
arteries
muscle
large
present
space
thin
outer
through
outer
layer
of
collagen bres
which
layer
semi-lunar
blood flows
capillary
only
an
valves
prevent
endothelium,
no other
short
cells or bres
red
blood
a
diffusion
vessels
of
blood
distance
so
no
cell
is far from
a
capillary
cells
pores
inside
thin
backow
between
the
endothelial
perforated
with
pores
to
allow
water
and
capillary
cells
solutes
to
pass
out
into
tissue uid
by
pressure ltration
When
the
heart
contracts,
blood
surges
into
the
arteries.
The
high
blood
S tudy
pressure
in
the
causes
blood
the
aorta,
stretches
the
which
elastic
is
an
elastic
bres.
The
artery,
ow
of
to
widen.
blood
in
The
foc us
energy
arteries
is
Answer Question
pulsatile;
energy
the
as
the
stored
blood
blood
in
their
forwards.
pressure
falls
stretched
The
the
state
stretch
and
is
elastic
bres
returned
recoil
to
means
recoil
the
that
so
that
blood.
the
This
blood
the
about the factors that
end
than
of
high
for
in
the
the
Arterioles
the
main
aorta.
arteries,
blood
to
provide
a
Blood
as
they
ow
pressure
enter
the
straight
resistance
to
entering
organs,
into
the
blood
the
small
is
thin-walled
ow
which
98 to nd
the
exchange of water
inuence
forces
and
solutes
pressure
only
plasma
and tissue uid
slightly
as
less
page
out
between the
at
2 on
the
arteries
is
blood ows through
capillaries.
too
capillaries.
reduces
the
blood
Summary q uestions
pressure.
pass
Flow
through
is
still
pulsatile,
capillaries
but
without
the
pressure
bursting
them,
becomes
but
high
low
enough
enough
to
to
1
enable
pressure
filtration
to
occur
(see
page
Explain how capillaries are adapted
114).
for the functions they carry out.
Blood
that
ows
out
of
capillaries
has
a
very
low
blood
pressure,
which
2
makes
it
difcult
for
blood
to
return
to
the
heart
in
veins.
The
blood
is
Explain the roles of the following
in
in blood vessels: endothelium,
danger
of
pooling
in
the
veins
or
owing
backwards.
The
contraction
of
smooth muscle, collagen, elastic
skeletal
muscles
around
the
veins
squeezes
them
and
helps
to
push
blood
tissue.
along.
helps
with
The
The
to
pressure
draw
blood
it
blood
has
semi-lunar
a
in
the
back
chest
into
negative
valves
decreases
the
heart.
pressure,
prevent
when
When
which
backow
by
you
the
also
breathe
heart
draws
lling
and
in
and
expands
blood
closing
to
from
veins
this
ll
3
veins.
contain
ows
the
wrong
why
the
walls
of
arteries
capillaries.
when
4
blood
Suggest
Name
an
artery
that
caries
way.
deoxygenated
that
5
carries
Make
a
veins
and
and
oxygenated
table
structure
blood
to
compare
and function
a
vein
blood.
of
the
arteries,
capillaries.
85
3.3
The
heart
Figure
Learning outcomes
The
On
completion
of
this
section,
3.3.1
heart
is
be
able
a
state
that
describe
mammals
the
structure

make
a
section
of
a
have
into
a
be
heart
external
the
and
internal
heart
drawing
of
external
muscular
structure
pump
that
of
the
forces
of
a
the
It
This
is
what
blood
pulmonary
pumped
a
into
good
happens
atria
and
consists
of
two
pumps
blood
through
working
in
the
series.
both
relax
the
ows
into
systemic
opportunity
as
it
beats.
ventricles
the
circulation;
side
of
the
blood
heart,
returns
which
to
the
pumps
heart
it
to
circulation.
to
watch
Y
ou
contract
right
oxygenated
an
should
to
force
animation
see
the
blood
of
events
out,
and
the
of
heart
systole,
diastole,
showing
when
when
the
they
longitudinal
and
ll
with
blood.
heart.
The
Blood vessel
Type of
table
shows
blood
the
functions
of
the
main
blood
cavae
vessels
near
the
heart.
Blood travelling
from
venae
heart.
to:
four-chambered

large
system.
Deoxygenated

the
you
circulatory
should
shows
deoxygenated
all
to
the
organs
except
the
right
atrium
lungs
pulmonary
arteries
deoxygenated
right
pulmonary
veins
oxygenated
lungs
left
oxygenated
left
all
aorta
ventricle
lungs
ventricle
atrium
the
organs
except
the
lungs
coronary
arteries
oxygenated
base
of
aortic
coronary
veins
deoxygenated
aorta
( just
above
capillaries
valve)
capillaries
within
heart
cardiac
muscle
aortic
within
heart
muscle
right
sinus
emptying
into
atrium
arch
superior
(anterior)
aorta
vena
cava
left
pulmonary
right
pulmonary
artery
pulmonary
artery
vena
cava
artery
pulmonary
pulmonary
veins
semi-lunar
veins
right
valves
left
atrium
coronary
cavity
of
artery
right
atrium
cavity
right
left
ventricle
coronary
left
right
artery
atrio-
valve
ventricular
cardiac
vein
tendons
valve
right
of
atrium
ventricle
inferior
(posterior)
vena
cava
vena
cava
left
descending
aorta
apex
cavity
right
Figure 3.3.1
of
ventriole
right
ventricle
The external structure of the heart showing the
ventricle
apex
septum
main blood vessels and the heart’s own blood supply
Figure 3.3.2
valves
86
The internal structure of the heart showing the four
Module
Structure
right
Function
atrium
tricuspid
collects
valve
deoxygenated
vena
right
ventricle
from
ventricle
right
collects
from
into
cava;
atrium
to
prevents
atrium;
pulmonary
blood
of
systole
diastole
contracts
relaxes
opens
closes
contracts
relaxes
contracts
relaxes
to
blood
right
blood
pumps
arteries
blood
to
lungs
Figure 3.3.3
left
atrium
collects
maintenance
backow
deoxygenated
right
blood
pumps
one-way ow
ventricle;
right
Biosystems
Action during
from
ensures
2
oxygenated
pulmonary
veins;
blood from
pumps
A heart dissected to show
the internal structures of the left-hand
side. You can see the left atrium, bicuspid
blood
valve, left ventricle, valve tendons and the
to
left
ventricle
papillary muscles at the base of the
tendons.
bicuspid
valve
ensures
from
one-way ow
left
atrium
prevents
left
ventricle
collects
left
left
blood
opens
closes
contracts
relaxes
ventricle;
backow
oxygenated
atrium;
aorta
to
of
and
pumps
blood from
blood
systemic
into
circulation
S tudy
semi-lunar
ensure
valves
from
one-way ow
of
blood
open
close
We
ventricles
into
have three types of
such
of
the
chambers
of
the
heart
are
different
thicknesses.
The
muscle,
as the
skeletal
walls
are
thinner
than
the
walls
of
the
ventricles
as
they
have
less
Atria
contract
to
develop
a
low
pressure
to
move
blood
into
muscle,
left
ventricle
which
blood
there
the
The
are
as
very
ow.
are
a
of
blood
The
left
the
the
tissue
capillaries.
to
ventricle
right
with
ventricle
arterioles
high
right
from
spongy
many
different
therefore
wall
pressure
is
blood
in
to
how
present
needed
is
the
and
the
high
a
rest
much
a
than
pumped
arterioles
determine
Arterioles
thinner
ventricle
few
pumps
is
the
to
low
of
the
is
to
is
which
as
its
attached to our
muscle,
which
all of the
appearance
lungs,
body,
in organs
name
skeleton;
makes
up
heart. They differ
in
the
to
and
in the
under the
microscope
way they function.
where
distributed
resistance
systemic
of
resistance
the
blood
wall
is
blood vessels;
the
almost
ventricles.
which
and
cardiac
cardiac
muscle.
gut
atrial
suggests
walls
muscle tissue:
arteries
smooth
The
foc us
ow
into
and
circulation.
S tudy
foc us
Summary q uestions
Arterioles
1
Draw
a ow
through
the
chart
diagram
heart
and
to
show
through
the
the
pathway
pulmonary
taken
by
blood
as
it ows
circulation.
conditions
but
2
Outline
3
Describe
the
systemic
circulation
in
the
control
capillaries. They
they
by
are
pulmonary
4
State
valve,
5
the
artery
position
semi-lunar
Explain
and
why
the
in
of
the following
vein,
the
valves.
coronary
heart
of
chambers
of
the
blood
vessels:
opening
also
to
and
into
local
closing,
controlled
by
vena
cava,
aorta,
centre
in
the
the
cardiovascular
brain.
artery.
the following:
Describe
blood ow
body.
nerves from
the functions
the
respond
the function
heart
do
not
bicuspid
of
each
have
valve,
tricuspid
valve.
walls
of
the
same
thickness.
87
3.4
Pulse
and
blood
The
Learning outcomes
pulse
routinely
On
completion
of
this
section,
be
able
dene
the
terms
pulse
and
blood
the
role
of
blood
the
is
the factors
that
felt
as
by
the
aorta.
an
aspects
indication
a
surge
of
contraction
The
The
the
page
of
of
our
our
circulation
state
of
that
are
health.
blood
elastic
stretch
pulse.
The
of
tissue
and
the
ows
into
the
ventricle.
stretches
recoil
pulse
left
aorta
rate
travels
is
The
under
and
then
as
wave
a
equivalent
to
surge
recoils
along
the
of
blood
when
the
heart
the
arteries
rises
and
falls
considerably
in
the
left
ventricle
rate.
(see
The
Figure
93),
but
less
so
in
the
arteries
thanks
to
elastic
recoil.
table
gives
the
minimum,
maximum
and
normal
pulse
rates
and
pressure.
pressures
circulation.
exercise;
values
S tudy
foc us
vary
question
1
may
heart
calculate
cardiac
humans.
maximum
normal
apply
values
when
people
does
not
Blood
gures
are
people
so
it
pump
pressures
is
a
for
people
are
not
out
are
for
xed
more
blood
responds
pumping
pumped
out
out
beats
min
easy
volume
by
returns
in
the
by
expanding
the
increased
each
to
a
veins
to
of
per
greater
volume
ventricle
is
of
and
strenuous
minimum
and
decide
blood
systemic
the
rates
minute
the
Blood pressure in
cardiac
volume
blood
stroke
3
blood
what
all
the
is
pressures
‘normal’.
time.
During
than
per
during
at
rest.
beat.
volume.
diastole
The
The
This
and
volume
is
about
then
of
blood
between
3
at
60–80 cm
rate/
doing
rest,
Pulse
the
output.
heart
Pulse
for
people
at
asleep.
always
are
to nd
exercise,
to
for
The
the
amongst
The
Summary
how
contracts,
relaxes.
on
blood
out
give
two
affect
The
Answer
to
are
circulation
discuss
blood
the
pressure
3.6.2

pressure
pressure
blood
in
heart
created
stretches
and
explain
measured
the
ventricle
pressure

blood
to:
pressure

and
you
When
should
pressure
rest,
output
is
increasing
the
volume
to
200 cm
of
blood
during
pumped
strenuous
out
per
exercise.
The
minute.
–1
arteries/kPa (mmHg)
Pulse
Systolic
Diastolic
The
maximum
36.6
200
(275)
23.9
(180)
Y
ou
the
normal
60–100
minimum
40–50
15.8
(120)
13.3
(100)
10.5
(80)
8.0
(60)
person
your
right
should
wrist
artery
and
as
be
relax
the
mean
pulse
Now
star
for
take
30
while
you
second
until
the
Blood
Blood
are
pulse
the
pressure
88
Taking the pulse at the wrist
in
dilate
the
wait
radial
you
Make
sure
T
ake
rest
feel
your
another
could
spot
30
then
for
stabilises
is
in
to
2
vary
that
3
a
who
two
in
artery,
is
a
take
runs
swelling
sitting
minute
minutes
and
over
of
the
down
and
write
calculate
amongst
regular
of
photograph.
which
are
for
ngers
the
slight
you
pulse
or
as
considerably
those
do
for
repeat
each
at
step
a
ups,
few
seconds.
W
rite
this
your
shuttle
minutes.
your
people,
exercise
after
resting
runs,
Now
down
procedure
minute
rapidly
increase
as
arteries
all
and
by
If
The
of
the
body
but
and
your
so
ups,
your
pulse
you
exercise.
press
take
have
Keep
pulse
rate
30
going
value.
resistance
and
There
is
the
not
distribution
arterioles
all
blood
veins.
the
ows.
body.
it.
the
on
blood
the
determined
to
overcome
acting
which
vessels
is
needed
pressure
through
blood
drops
Figure 3.4.1
the
Place
way
pressure
capillaries
and
in
pulse.
same
volumes.
the
and
her
the
What
often
Y
ou
recorded
rate
at
are
on
then
waiting
pulse
atmospheric
vessels
exercise.
rates
it.
for
rates
in
pulse
minutes.
stroke
run
taking
skin.
this
rate
large
and
the
the
is
wrist
through
Pulse
just
seconds
feel
few
pulse
with
or
a
left
to
Repeat
rate.
some
jumps
to
surges
for
low
hearts
your
close
value.
with
photograph
on
able
blood
then
have
the
bones
down
those
in
hand
these
ows
that
into
at
ow
blood
once,
capillaries
to
the
blood
blood
to
ll
all
through
reduce
the
and
from
small
enough
of
constrict
open
to
many
blood
there
blood
ow
pressure
is
little
left
Module
Constricted
greatest
lungs
in
than
ventricle
diverted

is
greater
V
olume
of
(see
page
are
blood
to
be
left-hand
by
by
the
ow
fewer
pumped
than
on
of
blood.
arterioles
out
oxygenated
circulation.
side
three
the
are
by
and
This
the
the
blood
means
This
in
is
the
right
is
not
that
blood
right.
factors:
heart;
blood
pressure
increases
if
in
the
blood
blood
vessels;
vessels.
It
blood
falls
if
pressure
there
is
is
high
blood
loss
if
there
or
is
more
arteries;
harden.
blood
This
pressure
happens
rises
with
if
age
the
and
arteries
with
become
some
Figure 3.4.2
Link
161).
sensory
Taking blood pressure
diseases
cells
in
the
body
that
detect
changes
in
blood
pressure.
There
The
maintenance
capillaries.
the
or
the
systemic
pumped
in
into
of
elastic
the
all
to
There
Biosystems
increases.
blood
less
resistance
tissue
the
inuenced
blood
ows
as
lung
in
on
blood
of
of
Elasticity
There
is
volume
V
olume
blood
as
a
circulation.
organs
through
pressure
plenty

other
goes
stroke

in
provide
systemic
elsewhere
pressure
Blood
arterioles
the
2
cardiovascular
centre
in
the
brain
responds
by
coordinating
is
more
about
the
coordination
the
of
the
heart
and
blood
vessels
on
following:
page

changes

loss

constriction
or
blood
circulation;
of
in
the
water
heart
from
rate
the
and
strength
kidneys
if
the
of
90.
contraction
blood
volume
is
too
high,
and
S tudy
in
the
dilation
of
arterioles
to
constriction
alter
the
increases
distribution
the
blood
of
foc us
the
pressure
and
When you draw the
dilation
High
and
blood
decreases
low
blood
pressure
enough
may
oxygen.
problems,
such
it,
restoring
pressures
mean
High
as
so
that
blood
heart
are
it
to
indications
tissues,
pressure
of
people’s
especially
is
graph for
normal.
an
the
indicator
health.
brain,
of
do
many
Low
not
receive
health
disease.
Summary question
5, you
the vertical
pulse on the
axis for
can draw
left
and the vertical axis for blood pressure
on the
right. Alternatively, you
draw two
this,
separate
graphs.
put one directly
other
and
scale. This
use the
underneath the
same
helps to
can
If you do
horizontal
make
comparisons.
Summary q uestions
3
1
A
person
has
a
stroke
volume
at
rest
of
70 cm
. The
heart
Time/min
rate
The
is
75
beats
cardiac
3
25 dm
per
minute. Calculate
output for
a
man
doing
the
cardiac
strenuous
exercise
;
calculate
the
stroke
volume
if
the
rate/
beats
per
Blood
pressure/kPa
heart
min
Systolic
Diastolic
is
–1
min
Pulse
output.
rate
is
0
65
16.0
10.0
5
69
16.5
10.3
–1
120 beats min
2
Suggest
why
ventricles
volumes
3
Dene
the
terms
Distinguish
5
The
table
20
a
Draw
who
minutes
a
volumes
the
during
rates
rested for
graph
then
to
blood
at
ejected
any
one
by
time,
left
and
and
b
right
the
7
100
19.5
10.3
9
120
21.4
10.0
11
121
23.7
10.5
13
122
25.0
10.3
15
121
25.4
10.7
17
123
25.6
10.2
19
124
25.7
10.6
20
123
25.3
10.4
21
115
16.3
10.3
23
80
21.3
10.3
25
68
17
.3
10.2
exercise.
and
systolic
pulse
and
of
same
pulse rate
between
shows
athlete
for
the
always
increase
4
an
a
are
5
and
and
diastolic
blood
minutes,
rested
show
blood pressure
the
blood
pressure
took
pressures.
recordings for
vigorous
exercise
again.
changes
in
pulse
rate
and
blood
pressure.
b
Describe
pressure.
and
explain
the
changes
in
pulse
rate
and
blood
89
3.5
Control
of
the
Every
Learning outcomes
split
On
completion
should
be
able
of
this
section,
heart
time
second
arteries.
you
the
later
,
These
dene

state
the
term
nervous
myogenic
the
sino-atrial
node
heart’s
state
that
specialised
cells
throughout
explain
conduct
the
how
activity
discuss
affect
the
the
as
the
muscles
contract
heart
in
described
skeletal
comes
from
heart
the
of
brain
the
together
together
muscle
need
forcing
to
be
and
then,
blood
a
into
the
coordinated.
on
muscle
your
arms
pages
in
and
120
that
it
to
is
legs
125.
is
done
entirely
Cardiac
myogenic
as
muscle
the
by
the
is
stimulus
to
within
muscle
the
cells
muscle
that
itself.
initiate
There
(start)
is
a
the
system
heart
of
beat
impulses,
which
spread
across
cardiac
muscle
so
it
by
contracts
and
that
the
way.
It
ensures
ventricles
that
contract
the
from
ventricles
the
base
contract
upwards.
after
the
in
atria
This
system
is:
right
atrium;
inuences
sino -atrial
node
(SAN)
situated
in
the
muscle
of
the
this
heart
internal factors
heart
cardiac
coordinated
is

of
contract
impulses

the
ventricles
atria
cardiac
a

two
pacemaker
emitting
muscle
of
from
specialised

the
is
contract
the
the
actions
system
different
that
beats
to:
Coordination

heart
often
called
the
heart’s
‘pacemaker ’
that

atrioventricular

Purkyne
node
(A
VN)
situated
between
the
atria
and
the
ventricles
action.
bres
muscular
that
wall
run
between
down
the
towards
ventricles
the
and
apex
into
of
the
the
heart
within
ventricular
the
muscle.
Did you know?
S tudy
The
human
heart
beats
about
Muscles
–1
75 beats min
.
Heart
rates
of
are
very
resting
muscle. They
skeleton that we
are
not
use
myogenic. The
in
movement
instructions to
are
skeletal or
contract
come from
different. The
the
elephant’s
attached to the
other
striated
mammals
foc us
heart
rate
is
brain
and the
muscles
are
neurogenic.
about
–1
30 beats min
and
the
tiny
Etruscan
–1
pigmy
shrew’s
is
Cells
1500 beats min
in
the
impulses
Cardiac
SAN
that
act
travel
muscle
as
the
across
consists
of
heart’s
the
‘pacemaker ’
cardiac
muscle
interconnected
by
in
cells
emitting
the
so
atria.
that
the
superior
aorta
vena
impulse
cava
spreads
across
the
muscle
in
all
directions.
This
impulse
pulmonary
stimulates
the
atria,
which
begin
to
contract.
The
impulse
vein
sinoatrial
cannot
pass
directly
from
the
atria
to
the
ventricles
because
there
node
is
right
a
ring
of
impulse
atrium
passing
non-conducting
reaches
to
the
the
AVN
Purkyne
brous
where
bres
it
that
tissue
is
separating
slowed
conduct
for
the
the
0.1 s
two.
The
before
impulse
to
the
left
atrioventricular
base
of
the
ventricles,
and
then
to
the
rest
of
the
muscle
in
the
atrium
node
walls
of
the
ventricles
so
they
contract
from
the
bottom
upwards.
left
right
ventricle
ventricle
S tudy
foc us
Purkyne
tissue
Figure 3.5.1
‘The AVN
The positions of the SAN, AVN and
of
the
delays
and
relays’
–
a
way
to
remember
the
role
of
this
part
heart.
Purkyne fibres in the heart
The
but
AVN
after
therefore
a
short
The
heart
The
activity
rate
is
relays
the
impulse
from
the
SAN
to
the
ventricles,
delay.
not
entirely
dependent
on
the
rate
of
ring
of
the
SAN.
Did you know?
of
the
SAN
is
inuenced
by
the
nervous
system
and
by
hormones.
Purkyne bres
Purkyně
them.
named
(1787–1869)
His
Purkinje.
are
name
is
after Jan
who
also
discovered
spelt
as
The
cardiovascular
monitors
by

the
internal
The
heart
and
cardiac
accelerator
90
centre
rate
in
and
external
factors.
accelerator
nerves
to
the
medulla
increases
There
centre
the
SAN,
oblongata
and
are
sends
AVN
at
decreases
two
parts
impulses
and
the
the
to
via
base
rate
this
the
throughout
as
of
the
centre:
cardiac
the
brain
inuenced
heart.
Module

The
cardiac
inhibitory
centre
sends
impulses
via
2
the
brain
cardiac
Figure
The
decelerator
3.5.2
shows
terminals
of
the
the
neurotransmitter
nerves
to
the
SAN
arrangement
cardiac
of
these
accelerator
nor-adrenaline.
The
and
AVN.
nerves.
nerve
SAN
release
also
the
responds
cardiac
to
the
hormone
adrenaline.
The
terminals
of
the
inhibitory
centre
cardiac
decelerator
decelerator
nerve
release
acetylcholine .
These
three
sinoatrial
nerve
chemicals
of
SAN
bind
cells
to
and
receptor
proteins
inuence
the
in
rate
at
the
cell
which
membranes
they
(inhibitory)
node
cardiac
emit
(SAN)
accelerator
atrioventricular
impulses.
centre
node
(AVN)
Did you know?
spinal
The
cardiac
nervous
accelerator
system
that
nerve
we
use
is
part
during
of
the
times
sympathetic
of
cord
(stimulatory)
danger
Figure 3.5.2
and
stress. The
cardiac
parasympathetic
decelerator
nervous
system
nerve
that,
is
part
of
amongst
the
other
The activity of the heart is controlled by the
cardiovascular centre in the brain, which sends impulses along
these nerves to increase or decrease heart rate and force of
things,
contraction
controls
digestion.
sympathetic
Some
system,
people
but
it
is
have
survived
impossible
to
without
survive
a
without
Did you know?
the
parasympathetic
system.
The
cardiac
part
Factors that
affect
heart
rate
a
of
Latin
There
Stretch
receptors
changes
to
the
in
in
blood
heart
in
the
aorta,
pressure.
the
vena
carotid
During
cava
arteries
exercise,
increases.
and
the
This
in
the
volume
increases
vena
of
cava
blood
the
and
increases
impulses
to
the
brain,
which
an
a
and
rate
via
carotid
increase
heart
in
the
cardiac
artery
are
impulses
accelerator
stimulated
in
the
by
cardiac
nerve.
high
When
blood
decelerator
receptors
of
pressure,
nerve
this
and
a
the
the
pass
neck
down
dioxide
and
oxygen
increases
and/or
increases
to
During
metabolism
heart
slows
nutrients,
such
mammals
that
oxygen
also
decrease
that
spend
rate
and
glucose.
in
long
diving
the
is
is
spend
mammals,
periods
the
dioxide
decreases,
decrease
demand
even
such
in
leads
to
decrease
the
the
the
spine
excitement,
exercise
increasing
the
the
and
then
stimulating
the
more
as
as
for
and
thorax
an
viscera
in
and
even
viscera
the
most
and
or
the
gonads. The
comes from
bowels
of
the
Latin
guts.
carbon
concentration
heart
in
seals,
the
rate
Summary q uestions
and
down
dormancy.
dolphins
1
Dene
2
Explain
the
term
myogenic
body ’s
oxygen
slowing
periods
anticipation
brain
frequency
the
branch
the
innervating
in
and
in
those
Heart
rates
the
the
whales,
the
roles
initiation
heart
beat:
of
the following
and
control
SAN, AVN
of
and
Purkyne bres.
of
to
increase
impulses
in
of
danger
the
heart
the
cardiac
and
rate.
the
start
This
is
of
done
accelerator
The
SAN
830 ms
by
nerve
SAN
is
emits
in
a
not
release
of
adrenaline.
Both
stimulate
the
SAN
impulses
person
at
every
rest.
inuenced
by
If
the
any
and
other factors
by
side
submerged.
anger
,
stimulate
either
throughout
abdomen,
3
Pain,
the
blood.
less
long
changes
carbon
pressure
there
There
or
of
blood
and
hibernate
If
detect
concentration
oxygenation
down
as
arteries
concentrations.
the
improve
sleep,
carotid
that
brain. They
in
word for
the
nerves
hind
aorta
rate.
in
is
wandering.
these
originate from
term
Chemoreceptors
of
is
this
increase
in
meaning
pair
nerve
nerve. Vagus
returning
stretch
stimulates
word
is
‘wander’
heart
decelerator
vagus
detect
of
vein
the
what
is
the
heart
and
rate?
AVN
to
increase
the
heart
rate
and
force
of
contraction.
4
The
heart
rate
increases
during
digestion
to
increase
the
blood
supply
Explain
and
the
gut.
The
blood
supplies
oxygen
to
support
a
higher
rate
of
the
nutrients
needed
to
make
body
temperature
increases
during
a
fever
,
the
heart
rate
pump
more
blood
to
the
skin’s
hormonal
rate
Name
when
the
body
temperature
heart
rate
increases
with
system
the
heart
surface
to
lose
heat.
The
decreases
as
in
the factors
heart
inuence
beat.
rate.
that
Explain
inuence
how
the
rate
responds
to
changes
in
the
hypothermia.
factors
The
of
heart
heart
slows
system
increases
the
to
nervous
enzymes.
5
When
the
respiration
the
and
how
to
that
you
have
named.
age.
91
3.6
The
cardiac
cycle
On
Learning outcomes
page
86
Remember
On
completion
should

be
able
describe
of
this
section,
you
to:
the
changes
that
the
heart
during
saw
that
the
left
side
the
same
the
contraction
the
the
right
pumps
on
left
taken
side
of
oxygenated
and
of
route
right
the
as
two
by
the
heart
blood.
the
blood
two
it
ows
pumps
Changes
atria
ventricles.
as
The
deoxygenated
that
contract
two
through
occur
in
together
sides
of
the
the
heart.
blood
the
and
heart
followed
heart
are
by
go
occur
through
within
we
one
the
same
changes
simultaneously.
heart
beat
S tudy

explain
that
the
cardiac
usually
depicted
as
the
cycle
pressure
Trace
changes
that
occur
in
the
the
left
ventricle
explain
how
and
the
heart
pressure
open
and
atrioventricular
changes
close
and
in
to
ensure
taken
within
the
blood
using
through
Figure
the
3.3.2
heart
on
and
page
the
86.
pulmonary
Do
not
and
confuse
the
by
blood
heart
with
during
the
one
cardiac
heart
cycle,
which
is
the
changes
that
occur
beat.
the
biggest
changes
in
pressure
occur
on
the
left
side
of
the
heart
so
it
is
one-way ow
usually
of
by
by
semi-lunar
The
valves
taken
circulations
aorta
route

route
left
systemic
atrium,
foc us
is
the
left
that
is
used
to
show
the
cardiac
cycle
–
all
the
changes
blood.
that
occur
There
are
relaxed
in
and
valves
two
and
drawing
right
within
empty
main
lling
blood
left
into
pressure
are
during
phases
with
to
The
arteries
As
venae
blood
is
beginning
This
ll
heart
cardiac
this
cycle.
and
than
with
is
Imagine
the
the
though
phase
beat.
happens
cavae
ows
higher
to
one
the
blood.
the
ventricles.
the
and
heart
from
atria.
the
in
the
heart
the
open
blood.
T
o
make
heart
is
veins
into
the
atrioventricular
During
ventricles,
the
expands,
pulmonary
diastole.
the
that
this
which
sure
phase
are
blood
nearly
blood
does
not
from
from
ow
back
from
arteries
to
ventricles,
the
semi-lunar
valves
at
the
base
of
lungs
body
the
arteries
phase
the
heart
diastole
are
known
systole.
blood
right
left
atrium
atrium
into
on
the
either
Y
ou
can
graph
side
see
arteries.
of
As
SAN
contract
full
rst,
spreading
start
happens
because
systole
the
the
blood
This
begins,
so
contract
valves
contraction
open.
upwards
to
atrioventricular
the
emptying
valves
ventricular
and
ventricles
the
initiate
with
blood
and
pressures
into
atrial
squeezing
the
shut
is
are
opening
different
valves.
you
changes
are
the
the
atrioventricular
base
This
these
if
the
forcing
valves.
this
shows
at
from
atria
the
ventricles
increases,
semi-lunar
The
keeps
starting
the
Impulses
systole.
which
When
pressure
the
as
ventricles
contractions
filling
closed.
follow
in
the
blood
graph
pressure
in
in
Figure
the
3.6.2
left
side
carefully.
of
the
The
heart
during
left
one
heart
beat.
Follow
the
changes
by
putting
a
ruler
vertically
against
the
ventricle
y-axis
At
right
the
and
moving
beginning
it
of
to
the
the
right.
graph
the
heart
is
lling
with
blood.
The
left
ventricle
atrium
heart full of
and
left
ventricle
are
relaxed
and
blood
is
owing
from
the
blood
pulmonary
bicuspid
veins
valve
into
into
the
the
left
left
atrium.
ventricle.
Some
The
blood
SAN
ows
sends
through
out
an
the
impulse
open
and
to
to
the
atrial
muscles
contract.
Blood
pressure
rises
in
the
atrium
and
blood
lungs
is
forced
The
into
atrial
Purkyne
the
muscles
bres
contract.
left
to
Among
ventricle.
stop
contracting;
muscles
them
at
are
the
the
the
base
of
papillary
AVN
the
sends
impulses
ventricles
muscles
at
that
the
through
start
base
of
the
to
the
heart
tendons
of
the
bicuspid
tendons
become
valve.
The
papillary
muscles
contract,
the
valve
systole
pumping
Figure 3.6.1
Diagrams of the heart at
different stages of the cardiac cycle
92
upwards.
than
in
Blood
the
taut
is
aorta
and
forced
so
the
the
into
ventricle
the
contracts
aorta;
semi-lunar
pressure
valves
open.
from
is
the
bottom
greater
Pressure
in
is
the
ventricle
greater
in
the
Module
2
Biosystems
S tudy
left
atrium
left
ventricle
contracting
You
relaxing
should
graph.
It
maintenance
foc us
be
able
helps
to
interpret
to follow
the
this
changes
relaxing
in
semilunar
valve
opens
semilunar
valve
the
heart
with
searching for
(X)
an
animation. Try
closes
‘cardiac
cycle
(Y)
animation’
to nd
something
to
help
15
aPk
you.
/
erusserp
10
5
atrioventricular
atrioventricular
valve
closes
valve
S tudy
opens
foc us
(Z)
(W)
0
We
are
using
pressure
mc
3
the
is
SI
units
given
medical
as
in
this
kPa.
profession
book,
so
However,
uses
mmHg
/
elcirtnev tfel
(millimetres
150
pressure.
that
80’
If
your
then
of
a
mercury) for
health
blood
that
worker
pressure
is
is
a
systolic
and
a
diastolic
blood
tells
‘120
you
over
pressure
of
100
fo
120 mmHg
emulov
of
80 mmHg
and
is
pressure
perfectly
normal!
50
0
0.
1
0
0.3
0.2
Figure 3.6.2
/
0.7
0.6
0.5
0.4
time
0.8
s
This graph shows the pressure changes in the left side of the heart and the
aorta during one cardiac cycle
left
in
ventricle
the
than
tendons
atrium.
forced
Blood
out
of
in
the
prevents
pressure
the
left
the
rises
ventricles,
atrium
valve
to
a
the
so
the
from
peak
bicuspid
‘blowing
and
muscles
then
relax.
valve
back’
as
all
Blood
closes.
into
the
blood
has
pressure
T
ension
left
Summary q uestions
been
in
the
1
ventricle
falls,
but
thanks
to
elastic
recoil
in
the
aorta
the
pressure
Explain
term
maintained
below
the
above
that
pressure
in
in
the
the
ventricle.
aorta
so
the
Pressure
in
semi-lunar
the
ventricle
valves
close
from
the
aorta
into
the
ventricle.
As
pressure
lower
in
the
ventricle
than
in
the
atria
so
the
bicuspid
Explain
what
valves
graph
shows
that
at
W
and
Z
the
pressures
in
the
left
atrium
and
ventricle
the
W,
left
change
ventricle
the
with
and
respect
the
aorta
to
each
change
other
.
with
At
X
and
respect
to
Y,
the
one
Figure
3.6.2
pressure
This
in
forces
the
the
left
ventricle
bicuspid
valve
increases
to
close.
above
The
that
blood
‘aps’
of
the
valve
and
the
valve
tendons
prevent
the
in
the
moves
left
X,
the
the
into
the
Explain
valve
Y,
This
in
the
causes
left
the
ventricle
semi-lunar
increases
valves
to
so
that
open
so
it
is
above
that
blood
that
left
why
the
so
atria
Z,
blood
ventricle
that
aorta
the
in
it
lls
blood
the
blood
the
does
heart
in
pulmonary
not ow
the
venae
veins
while
is
relaxing
and
expanding.
The
blood
is
lower
the
than
‘pockets’
that
of
of
the
the
blood
semi-lunar
in
the
valves
left
pressure
atrium
of
so
the
the
ventricle
bicuspid
decreases
valve
to
blood-pressure
that
side
of
occur
the
on
heart
the
and
right-
in
pressure
aorta.
and
below
contract.
the
changes
The
they
pulmonary
that
of
artery
during
blood
cardiac
cycle. The
maximum
close.
blood
At
and
Sketch
one
from
beats
of
the
decreases
in
ows
aorta.
the
rate
‘blowing
hand
At
heart
minute.
atrium.
pressure
aorta.
the
0.8 s.
left
5
the
that
lasts for
under
the
At
one
pressures
cavae
into
shows
cycle
away from
back’
closes
during
another
.
4
atrium.
the
and
heart
the
per
At
opens
the
cycle.
Calculate
in
in
again.
cardiac
left
the
valve
3
The
by
it
cardiac
opens
meant
prevent
decreases
the
becomes
is
cardiac cycle
decreases
to
2
backow
what
is
the
artery
pressure
is
in
the
pulmonary
4.0 kPa.
opens.
93
3.7
Haemoglobin
Haemoglobin
Learning outcomes
four
On
completion
should
be
able
of
this
and
section,
you
parts
with
molecule

outline
the
structure
of
of
explain
molecule
is
are
two
associated
iron
changes
protein
in
the
shape,
how
haemoglobin
haem
Each
haemoglobin
to
form
the
transport
group.
When
easier
structure.
polypeptides
for
and
two
Oxygen
this
The
β-globin
combines
happens,
haemoglobin
molecule
can
transport
the
to
whole
accept
four
molecules
more
of
oxyhaemoglobin:
the
oxygen
one
interacts
molecule
→
4O
HbO
of
with
oxygen
oxygen
to
8
in
a
cooperative
haemoglobin
makes
it
fashion.
easier
The
to
binding
bind
dissociation
another;
adult
+
2
of
curve for
quaternary
haem
group.
it
of
Haemoglobin
describe
a
oxygen
is
oxygen

a
α-globin
with
making
Hb
suitable for
with
of
haemoglobin
oxygen

conjugated
Each
the
transport
a
oxygen.
molecule
a
the
polypeptides.
loosely
to:
of
is
the
once
the
second
one
has
bound,
it
makes
it
easier
to
bind
the
human
third
and
so
on.
This
cooperative
binding
is
responsible
for
the
results
haemoglobin
obtained

explain
what
the
shows
about
the
supply
is
S tudy
haemoglobin
oxygen
bright
foc us
dark
a
good
idea
to
revise
binds
of
it
at
all
oxygen
is
a
it
dark
Deoxygenated
volume
in
haemoglobin
to
take
up
changes
of
red
colour
.
blood
oxygen
colour
.
Blood
that
in
that
the
Oxygenated
does
body
has
haemoglobin
blood
about
can
in
not
70%
carry
the
have
of
and
body
the
is
also
fairly
colour
.
pressure
example,
is
the
the
pressure
atmosphere
exerted
is
a
by
one
mixture
of
gas
as
oxygen,
part
of
a
carbon
gas
mixture.
dioxide,
haemoglobin from Unit
nitrogen
before
reading
these
two
haemoglobin
and
and
other
gases.
The
percentage
by
volume
of
oxygen
is
21%.
sections
The
on
of
the
For
structure
in
red.
red
Partial
1
ability
oxygen.
maximum
is
the
oxygen.
any
It
into
transport
As
of
investigations
dissociation
and
curve
from
transport
pressure
exerted
by
the
atmosphere
is
101.32 kPa,
so
the
partial
of
pressure
of
oxygen
)
( pO
is
21.28 kPa.
Blood
is
oxygenated
in
the
alveoli
2
oxygen
and
carbon
dioxide
in
the
in
blood.
See
1.8
in
Module
1
of Unit
the
lungs
where
more
humid
means
the
in
shape
of
a
pressure
oxygen
the
in
pO
is
less
water
the
–
it
is
vapour
alveolar
air
allostery. The
non-competitive
concentration
of
is
the
same,
but
about
exerts
is
a
13%
since
partial
the
in
is
Module
binding
inhibitors
another
1
of Unit
to
parts
of
the
much
This
Partial
example.
oxygen
can
be
equated
pressures
See
3.5
1.
The
in
in
with
the
tissues
are
oxygen
is
of
much
being
The
13.3
oxygen
lower
used
table
pressures
as
of
parts
of
5.0
shows
oxygen
the
muscle
in
muscle,
e.g.
3.5
in
during
different
)/kPa
2
active
partial
(pO
partial
atmosphere.
concentrations
respiration.
Did you know?
pressure of
body
resting
strenuous
body.
exercise
3
100 cm
is
too.
13.3 kPa.
Tissues
of
different
the
Each
air
pressure
lungs
enzymes
the
oxygen
protein
in
is
air
2
The
molecule
of
and
Link
change
total
1.
concentration
The
the
of
blood
of
oxygen. About
can
carry
3
about
20 cm
3
0.3 cm
same
of
oxygen
volume
oxygen
of
know
it
animals,
copper
such
rather
molecules
animal
would
be
as
in
life
as
like
we
impossible.
lobsters,
than
iron
in
Thought
experiment
Y
ou
know
the
water. Without
transport
haemoglobin,
dissolves
have
transporting
that
you
experiment.
exposed
to
changes
can
We
increasing
of
in
availability
haemoglobin
carry
will
out
think
in
in
schools
through
concentrations
of
the
of
oxygen
blood.
or
what
inuence
This
colleges,
happens
is
so
the
not
an
let’s
do
when
a
blood
is
oxygen.
blood
start
with
let’s
just
see
what
happens
to
blood
when
exposed
to
oxygen.
oxygen.
Blood
of
oxygen
to
stand,
This
94
how
capacity
thought
T
o
for
to
investigation
Some
their
need
oxygen-carrying
is
in
the
our
it
taken
even
colour
blood
from
a
though
goes
sample
vein
it
even
is
is
dark
called
darker
which
has
red
in
colour
.
deoxygenated
as
no
oxygen
oxygen
blood.
leaves
in
it.
This
the
has
If
quite
this
is
a
lot
left
haemoglobin.
Module
Part
A.
Bubble
some
oxygen
from
an
oxygen
cylinder
through
some
of
2
Biosystems
the
S tudy
blood
sample.
The
equal
volumes
blood
will
become
3
(e.g.
much
brighter
red.
If
you
5 cm
)
of
this
bright
red
blood
with
the
dark
This
red
blood,
you
will
have
an
intermediate
colour
which
has
50%
of
thought
volume
of
oxygen
that
the
blood
will
carry.
Carry
on
experiment
can
be
the
carried
maximum
foc us
mix
3
+
5 cm
a
maintenance
out for
real
with
equipment
doing
that
controls
the
pressure
of
the
3
this
with
other
mixtures
of
these
two
samples
of
blood
(e.g.
+
7.5 cm
gases
and
determines
the
percentage
3
)
2.5 cm
and
record
the
colours.
saturation
Part
in
B.
it)
the
Now
and
a
valve
take
another
cylinder
on
the
of
sample
oxygen
nitrogen
of
and
cylinder
dark
a
red
blood
cylinder
and
of
expose
(without
nitrogen.
the
blood
any
Start
to
oxygen
by
opening
nitrogen
at
recording
of
haemoglobin
changes
the
blood. The
the
pO
in
the
graph
is
by
colour
printed
of
out
as
the
changes.
2
pressure
of
air
haemoglobin
nitrogen
low
be
in
the
nitrogen
lungs.
of
not
and
W
atch
at
the
the
is
until
colour
blood
remains
nitrogen.
the
Keep
oxygen
oxygen
The
absorb
open
Look
some
and
lungs.
oxygen.
lungs.
as
the
does
slightly
pressure
slightly
in
valve
the
of
total
colour
of
Now
the
gas
the
Now
it
the
change
as
you
dark
reduce
oxygen
keep
gas
red
the
pressure
It
the
will
mixture
the
to
same
in
the
the
as
of
as
it
a
very
Summary q uestions
would
very
pressures
alveoli
oxygen
the
allow
change
changing
increase
colour
cylinder
pressure
blood.
absorbed.
reaches
a
in
pressure
of
the
up
Use
the
and
in
found
in
the
3.7
.
1
have
blood
dark
comparing
the
results
red
to
from
bright
colours
with
our
red.
our
It
thought
is
experiment:
possible
mixtures
of
to
the
quantify
blood
made
colours
these
in
part
of
results
the
Is
the
low
by
percentage
3.7.1
shows
the
results
of
our
thought
experiment
when
oxygen
these
saturation
with
the
is
a
oxygen
of
partial
low,
and
high
pressure
b
or
of
high?
A.
2
Figure
section
alveoli.
qualitative
from
this
answer
to
haemoglobin
W
e
in
to
questions.
1
that
information
Figure
plotted
on
a
What
is
the
likely
percentage
graph.
saturation
a
the
c
active
of
lungs,
haemoglobin
b
resting
in
muscle,
and
100
80
3
htiw
f o noitarutas
negyxo
muscle?
What
happens
to
the
saturation
of
the
pressure
percentage
haemoglobin
as
60
partial
egatnecrep
nibolgomeah
decreases
to
the
of
oxygen
likely
range
in
40
the
20
4
The
of
tissues?
P50
is
oxygen
the
at
partial
which
pressure
the
Figure 3.7.1
0
haemoglobin
0
2
4
6
partial
Why
is
when
this
you
curve(s)
read
to
the
(which
from
right
a
the
represents
left
called
an
right.
left,
you
With
loading
represents
to
pressure
oxygen
graph
8
of
of
12
start
this
at
the
graph
with
unloading
of
dissociation
it
is
(on
better
oxygen
oxygen
dissociates
dissociation curve
origin
from
in
the
to
the
from
curve?
left)
start
and
at
lungs)
the
follow
the
and
blood).
Remember
,
as
you
answer
the
oxyhaemoglobin
questions,
that
the
right
move
As
–
with
oxygen.
your
graph.
you
the
5
does
(which
respond
to
tissues
the
read
hence
graph
How
and
of
response
an
of
experiment
haemoglobin
to
investigate
to
the
graph
of
oxygen.
represent
the
Some
S tudy
points
in
–
but
only
a
few.
Notice
that
What
part
of
the
line
coincides
is
the
Make
a
copy
of
the
pressures
where
of
oxygen
in
the
respiring
oxyhaemoglobin
75%,
haemoglobin
dissociation
provide
decrease
them
in
the
with
oxygen.
in
pO
the
dissociates
A
respiring
oxygen?
the
pressure
of
percentage
of
and
haemoglobin
b
is
90%?
The
on
a
piece
of
graph
partial
can
annotate
show
which
your
part
is
slight
tissues
to
loading
which
in
part
is
the
pressure
of
oxygen
curve
the
lungs
is
13
kPa. What
paper. You
graph
to
the
percentage
to
if
the
partial
pressure
equivalent
in
to
of
oxygen
saturation
tissues
lot
partial
when
happens
partial
a
through
actively
on
the
the
with
are
up
saturation
foc us
in
steep
blood ows
the
7
body
as
the
different
situation
P50 from
the
shows
a
concentrations
saturated
the
oxyhaemoglobin
that
using
oxygen
results
50%
State
Normally
6
name.
is
An oxygen haemoglobin
14
oxygen/kPa
haemoglobin
blood
oxygen
10
lungs
the
lungs falls
slightly?
and
equivalent
8
to
Explain
how
haemoglobin
is
2
stimulates
a
lot
of
oxyhaemoglobin
dissociation,
giving
its
with
oxygen
to
the
unloading
in
to
the
answer
the
tissues. Use
questions.
it
adapted
the
to
lungs
transfer
to
the
oxygen from
tissues.
tissues.
95
3.8
Haemoglobin
and
the
transport
of
carbon
dioxide
More
Learning outcomes
for
On
completion
of
this
section,
you
carbon
this

be
lists
able
the
dioxide
that
a
ions
(HCO
is
of
),
transported
the
carbon
which
are
in
the
blood.
dioxide
is
transported
The
reason
converted
in
the
into
plasma
to
buffer
the
blood
against
changes
in
and
pH.
to:
ways
is
oxygen
proportion
3
help
in
which
carbon
Loading the
dioxide
than
large
hydrogencarbonate
which
should
is
transported
in
blood
with
carbon dioxide
the
Carbon
dioxide
diffuses
into
the
blood
from
respiring
cells.
It
is
highly
soluble
blood
in

explain
the
role
of
water
and
in
the
transport

dioxide
describe
dioxide
the
on
the
plasma
not
effect
haemoglobin
it
dissolves
in
the
plasma.
About
5%
of
carbon
dioxide
of
in
the
blood
is
carried
this
way
.
Some
also
reacts
with
water
in
of
the
carbon
of
carbonic
transported
anhydrase
some
carbon
to
catalysed
form
by
hydrogencarbonate
an
enzyme.
concentration
gradient
diffuses
through
easily
into
the
Most
red
ve
of
the
blood
cell
ions,
but
carbon
cells.
surface
this
is
a
dioxide
Carbon
slow
diffuses
dioxide
membranes
reaction
is
into
down
not
red
as
polar
,
blood
it
is
its
so
it
cells.
oxygen
dissociation
curve.
Some
of
–NH
terminals
the
carbon
of
dioxide
the
that
enters
polypeptides
red
that
blood
make
cells
up
combines
haemoglobin
with
to
the
form
2
carbaminohaemoglobin .
transported
S tudy
are
the ve
membranes
that
cell
carbon
remaining
ions.
surface
dioxide
Inside
anhydrase,
85%
red
of
blood
which
carbon
cells
diffuse
also
pass
through
intracellular
pages
dioxide
in
the
blood
is
is
transported
of
the
as
hydrogencarbonate
enzyme
carbonic
reaction:
anhydrase
carbonic
water
hydrogen
→
hydrogencarbonate
→
membranes from
production. What
are
+
acid
ion
ion
their
carbonic
See
carbon
two
+
of
the
molecules
this
dioxide
site
of
through? They
carbon
will
10%
dioxide
are
catalyses
carbonic
molecules
About
way.
foc us
The
What
this
anhydrase
they?
+
CO
84
and
24 for
answers.
Did you know?
enzyme
into
hydrogen
two
dioxide
Let’s
anhydrase
is
one
in
take
acting
O
→
H
ions
the
the
is
CO
2
catalyses
ions
the
and
most
→
H
+
HCO
3
3
formation
of
carbonic
hydrogencarbonate
important
for
the
acid,
ions.
which
What
transport
of
dissociates
happens
oxygen
next
and
to
carbon
blood.
hydrogencarbonate
ions
rst.
While
the
red
blood
cells
are
of
travelling
the fastest
H
2
The
these
Carbonic
+
2
the
enzymes.
along
capillaries
in
respiring
tissues,
the
hydrogencarbonate
ions
Its
accumulate
inside
the
cytoplasm
of
the
red
blood
cells.
Their
−1
turnover
number
is
600 000 s
,
concentration
which
means
that
as
cells
though
capillaries
tissues,
one
in
respiring
molecule
can
through
to
600 000
associate
molecules
of
per
second,
with
for
the
cells
into
hydrogencarbonate
the
lungs
reaction
it
just
catalyses
as
rapidly.
the
reverse
lower
ions
sodium
hydrogen
they
the
plasma
into
the
so
they
plasma
diffuse
where
out
of
the
they
ions.
would
ions.
If
lower
Haemoglobin
on
as
the
When
it
constant
the
absorbed
carbon
which
is
the
the
these
the
acts
as
rate
there
by
of
of
a
dioxide
allows
lead
When
were
pH
and
buffer
,
to
in
oxygen
to
the
for
allowed
this
to
would
absorbing
of
happens
oxygen.
accumulate
decrease
the
from
in
the
hydrogen
blood
aerobic
reduces
production
the
increases
more
as
ions
red
activity
ions
oxygen
stimulates:
in
the
of
effect
it
the
link
reliance
lactate
the
to
and
in
in
release
occur
of
to
of
and
anaerobic
last
The
the
cells,
during
more
are
in
oxygen,
decarboxylation
Krebs
cycle.
respiration,
to
has
tissues.
increase
more
more
a
sentence
dioxide
tissue
red
have
hydrogen
respiring
the
with
eventually
that
muscle
in
of
carbon
released.
reaction
on
Read
that
does
is
haemoglobin
absorption
produced
respiration
compounds
makes
oxyhaemoglobin
hydrogen
so
it
The
oxyhaemoglobin.
understanding
more
more
this
afnity
haemoglobin
dissociation
would
or
respiration
are
intermediate
extra
pH.
dissociation
key
unloading
exercise,
of
a
‘attractiveness’
promotes
again
96
in
proteins
ions.
maintain
In
that
converting
enzymes.
them
than
channel
carbon
blood
dioxide
greater
special
process
Now
up
is
blood ows
fatigue.
This
which
Module
2
Biosystems
maintenance
100
partial
f o noitarutas
CO
S tudy
pressure
1.0
foc us
kPa
2
2
O htiw
80
Look
partial
carefully
dissociation
CO
at
the
oxygen
pressure
1.5
curves
in
Figure
3.8.
1
kPa
2
egatnecrep
nibolgomeah
60
and
re-read
loading
40
Notice
the
blood
where
paragraphs
with
the
Oxyhaemoglobin
20
tissues
because
carbon
word
the
dioxide.
more
unloads
of
about
is
used.
oxygen
low
pO
in
but,
if
2
the
pCO
in
the
tissues
increases,
2
this
0
0
2
4
8
6
10
12
stimulates
more.
partial
pressure
it
to
unload
even
14
Do
not forget
to
use
the
word
/kPa
of O
2
‘more’
Figure 3.8.1
when
explaining
this
effect.
This graph shows the results of an investigation to find the effect of carbon
dioxide on the oxygen dissociation curve
Unloading
When
the
reverse.
carbon dioxide from the
blood
There
reaches
is
a
low
the
lungs,
all
concentration
the
of
blood
changes
carbon
described
dioxide
in
above
the
go
lungs
into
so
S tudy
some
carbon
dioxide
concentration
of
starts
oxygen
diffusing
in
the
out
alveoli
of
and
the
blood.
this
Also,
diffuses
there
into
the
is
red
a
blood
What
cells.
At
high
concentrations
of
oxygen
haemoglobin
has
a
higher
foc us
high
are
the ve
membranes
for
oxygen
than
hydrogen
ions,
so
these
leave
and
provide
a
substrate
reaction
catalysed
by
carbonic
that
surface
carbon
dioxide
for
molecules
the
cell
afnity
diffuse
through
in
the
anhydrase:
lungs?
carbonic
anhydrase
+
H
+
HCO
→
H
3
The
red
carbon
cells,
dioxide
through
diffuses
ve
cell
CO
2
down
surface
→
H
3
its
O
+
CO
2
2
concentration
membranes
into
gradient
the
out
of
the
alveoli.
Did you know?
The
can
effect
be
study
seen
this
difference
this,
of
put
tissues.
x-axis.
in
the
graph
ruler
Y
ou
Put
at
could
your
with
dioxide
graph.
more
between
a
saturation
that
carbon
The
choose
oxyhaemoglobin
is
is
The
any
less
when
unloads
more
shifted
each
of
partial
and
of
to
important
at
pressure
vertically
oxygen
saturation
curve
saturations
partial
ruler
the
carefully
.
the
a
on
the
pressure
off
carbon
right.
point
partial
oxygen
read
haemoglobin
Use
about
pressure
between
values
of
dioxide
is
3
and
from
a
this
corresponding
the
with
oxygen
ruler
is
oxygen.
to
that
5 kPa
the
present.
This
to
the
the
T
o
in
on
with
the
after
Christian
The
of
oxygen
effect
the
y-axis.
This
see
effect
is
of
it.
the famous
dioxide
on
haemoglobin
known
the
Bohr
discovered
means
carbon
saturation
as
Danish
the
(1855–1911)
His
son
Bohr
physiologist
was
who
Niels
Bohr,
physicist.
oxygen.
Summary q uestions
1
Describe
cells
to
how
red
carbon
blood
dioxide
passes from
respiring
cells.
5
Copy
a
2
a
State four
ways
in
Figure
which
carbon
dioxide
in
the
The
partial
which
of
these
is
the
the
most
of
the
carbon
and
answer
these
pressure
saturation
of
oxygen
of
in
tissues
haemoglobin
is
with
5.0 kPa.
oxygen
pCO
is
1.0 kPa
and
1.5 kPa.
Describe
Explain the role of carbonic anhydrase in red blood cells.
Explain
carbon
the
role
of
the following
in
anhydrase
the
transport
of
State
the
haemoglobin
c
plasma.
of
increasing
with
name
on
the
the
carbon
saturation
of
oxygen.
given
to
the
effect
you
have
described.
d
Explain
the
delivery
b
effect
concentration
haemoglobin
c
dioxide:
carbonic
the
dioxide.
dioxide
a
paper
responsible for
b
4
graph
2
Explain
transporting
3
to
blood.
when
b
on
is
State
transported
3.8.
1
questions:
of
signicance
oxygen
to
of
this
respiring
effect
in
the
tissues.
97
3.9
Practice
The
Answers to
1
a
all
Explain
The
total
some
why
was
multicellular
need
diameter
also
of
three
a
the
were
can
animals,
transport
and
blood vessels
thickness
mammalian
exam-style questions
mammals,
exam-style
the
measured. The
tissues
in
determined. The
the
b
walls
results
are
walls
i
ii
the
table.
c
i
pressures
along
Calculate
the
the
at
in
the
length
effective
the
two
table
of
the
blood
ends
of
do
not
capillary.
[2]
pressure for
the
capillary.
[2]
Blood vessels
ii
Artery
Vein
Capillary
4.0
5.0
0.008
Use
the
overall
blood
[1]
other
change
filtration
Feature
pressure of the
decreases
these vessels
the
why:
the hydrostatic
of
relative
of
in
Explain
[3]
of
system
accompanying CD.
as
system.
thickness
circulatory
be found on the
such
questions:
diameter/mm
thickness
of
thickness
of
wall/mm
1.0
0.5
0.0005
0.5
0.5
0.5
of
d
the
results
directions
the
of
your
taken
calculation
by fluid
at
to
the
state
two
ends
capillary.
[2]
Explain:
i
the
role
ii
how
of
tissue fluid
its volume
is
[1]
kept
constant.
[2]
endothelium/µm
thickness
of
elastic
0.730
0.025
3
0
Figure
the
a
of
smooth
0.34
0.30
is
a
diagram
B
of
A
tissue/mm
thickness
3.9.
1
heart.
i
Name A, B, C and D. [4]
ii
Explain
C
0
why
the
muscle/mm
D
chambers
b
Describe
walls
of
the functions
of
the
three
tissues
in
the
blood vessels.
and
[3]
Y
labelled
have
different
walls
X
of
thickness.
[3]
X
c
i
Calculate, for
each
blood vessel,
the
b
wall
Explain
the
meanings
of
Y
thickness
as
a
percentage
of
the
the
overall
terms
i
blood pressure,
Figure 3.9.1
diameter.
ii
Discuss
the
significance
calculations for
the
of
the
transport
results
of
of
blood
a
The
to function
table
exchange
shows
the
between
a
as
of
capillaries
that
capillary
involved
and
the
in
pulse.
the
[2]
roles
atrioventricular
controlling
4
allow
exchange vessels.
pressures
ii
Explain
[4]
State THREE features
them
c
your
in
these vessels.
2
and
[2]
[3]
The
out
cardiac
by
The
the
surrounding
the
of
output
diagram
is
shows
cycle
over
sino-atrial
and
beating
a
of
in
1
the
node,
Purkyne fibres
the
the volume
each ventricle
cardiac
the
node
in
heart.
of
[6]
blood
pumped
minute.
events
period
of
that
two
occur
in
seconds.
the
During
3
tissue fluid. The
the
arteriolar
distance
end
and
along
the
capillary
the venule
end
Arteriolar
end
is
between
this
time
the
was
75 cm
0.8 mm.
0
Pressures
stroke volume
Venule
0.5
1
1.5
2
end
time/s
atrial
hydrostatic
of
pressure
4.26
a
potential
of
3.33
b
pressure
i
Calculate
the
heart
ii
Calculate
the
cardiac
0.07
diastole
rate.
[1]
State THREE
output.
internal factors
that
[1]
influence
the
0.07
cardiac
of
systole
3.33
blood/kPa
hydrostatic
ventricular
Figure 3.9.2
blood/kPa
solute
systole
1.33
output.
[3]
tissue uid/kPa
c
solute
potential
of
0.67
Describe
the
roles
of
the following
in
the
action
0.67
of
the
heart:
tissue uid/kPa
i
atrioventricular
septum
ii
bicuspid valve
iii
papillary
iv
semi-lunar valve
[1]
[1]
The formula for effective blood pressure for filtration is:
(HP
of
(SP
98
blood
of
–
blood
HP
– SP
of
of
tissue fluid)
tissue fluid)
–
muscle
[1]
at
the
base
of
the
aorta.
[1]
Module
5
a
Describe
what
b
Describe
how
happens
in
the
heart
during
one
cardiac
cycle.
i
the
sudden
heart
responds
demands
of
of
a
exercise
at
an
increase
in
race
could
Explain
in
6
a
b
how
are
the
blood
pressure.
some
have
responses
a
you
have
described
distance
[4]
closed,
double
circulatory
one.
Plot
area
and
Explain
what
is
meant
by
this
blood
(e.g.
Discuss
the
table
gives
advantages
The
table
also
data
statement.
of
this
type
on five features
see
vessels
of
each
arterioles,
all
type
the
total
given
capillaries,
Blood vessel
table
in
of
circulatory
of
six
different
cross-sectional
the
table:
all veins
Length/mm
the
to
draw
x-axis
and
the
of
the
the
axis)
to
each
cross-sectional
blood ow
the
relationship
on
between
the
the
graph
two
system.
through
area
aorta,
both venae
the
[3]
have
to
do
this
because
blood vessels.
of
all
all
the
range
of
lengths
is
so
great.
blood
arteries,
all
cavae.
Overall
Lumen
diameter/mm
sectional
cross-
Blood
pressure/kPa
Speed of
blood
–1
area/mm
flow/mm
Minimum
left
s
Maximum
550.0
25.00
250
12
18
40
35.0
2.00
500
10
16
40
4 000
9
14
10
170 000
8
11
3
renal
as
systemic
2
aorta
the
same
[2]
the
shows
the
giving
on
the gures for
circulation. You
The
in
Make
vessels,
10 mm
speed
blood ows
ii
data
graphs.
system.
to
i
the
[1]
coordinated.
Mammals
use
[2]
different
c
foc us
the
yourself
ii
maintenance
to:
You
beginning
Biosystems
[6]
S tudy
the
2
artery
arteriole
3.0
0.07
capillary
0.8
0.008
left
renal
vena
7
cava
b
Describe
c
Explain
d
There
flow
One
of
vein
and
why
is
not
75.0
6.00
25 000
1
300.0
12.50
1 000
–2
explain
two
enough
through
the
blood
blood
organs
the functions
of
relationship
pressures
is
in
the
human
controlled
blood
is
to
between
(maximum
to
body
make
transport
the
and
diameter
minimum)
to fill
sure
that
all
of
of
the
demands
carbon
given for
capillaries
of
and
each
at
different
0.3
0.5
the vessels
are
0.
1
the
the
20
speed
of
the
blood.
[3]
blood vessel.
same
tissues
are
time.
[3]
Explain
how
blood
met.
[3]
100
dioxide.
partial
a
Outline
shows
dioxide
the
on
respiring
effect
the
of
when
partial
[5]
pressures
dissociation
curve
haemoglobin.
of 5.0 kPa at the two partial
pO
2
pressures of carbon dioxide, 1.0 kPa and 1.5 kPa.
c
i
State
the
pCO
on
name
the
of
the
effect
saturation
of
of
[1]
80
1.0
kPa
60
partial
pressure CO
2
1.5
kPa
40
20
increasing
haemoglobin
2
egatnecrep
State the percentage saturation of haemoglobin
with oxygen at a
pressure CO
it
cells.
two
oxygen
dioxide
nibolgomeah
for
b
3.9.3
carbon
carbon
O htiw
of
blood from
to
2
Figure
the
happens
f o noitarutas
enters
what
with
2
oxygen.
[1]
0
ii
Explain
how
ensures
tissues
an
the
effect
efficient
during
you
have
delivery
exercise.
of
0
named
oxygen
2
4
partial
to
6
pressure
8
of O
10
12
/kPa
2
[4]
Figure 3.9.3
99
2
Bosystems
4.
1
Homeostass
Learning outcomes
mantenance
Working
Y
ou
On
completion
of
this
section,
will
recall
be
able
dene
point,
and

the
terms
homeostasis,
set
negative feedback, receptor
effector
explain
the
effectors
in
of
will
roles
of
receptors
and
in
then
stop.
a
to
enzymes
Most
keep
explain
enzymes
Changes
work
in
efciently
these
two
if
kept
factors
at
cause
a
the
the
enzymes
multicellular
reactions
to
denatured
work
in
inside
the
organism
change.
and
the
cells.
cytoplasm
there
is
a
If
The
and
limit
the
changes
reactions
to
cells
have
nucleus
what
they
are
catalyse
various
constant,
each
can
but
achieve.
homeostatic
near
concept
homeostatic

that
pH.
are
conditions
Homeostasis
explain
1
and
enzyme-catalysed
extreme
ways
mechanisms

Unit
temperature
to:
rates

from
you
constant
should
efficiently
that
and
of
using
the
maintenance
level.
various
This
ways
is
to
of
done
conditions
by
inside
monitoring
maintain
these
the
body
physiological
within
narrow
at
a
factors
limits.
equilibrium
negative feedback
mechanisms
is
constant
are
Temperature
control
dynamic.
Birds
and
methods
these
mammals
to
control
animals
are
the
their
varies,
only
own
but
it
animals
body
is
that
have
temperature.
usually
complex
The
somewhere
in
body
the
physiological
temperature
range
of
35 °C
of
to
Link
42 °C.
below)
This
the
is
a
good
effect
enzyme
and
3.6
of
opportunity
temperature
Module
1
1.
of Unit
only
that
of
can
their
they
maintain
surroundings,
the
temperature
they
can
keep
it
above
(or
slightly
constant.
revise
and
activity from Unit
in
to
Not
pH
See
on
T
emperature
control
is
achieved
by:
3.5

monitoring

comparing
the
temperature
of
the
body
and
the
surroundings
1.
the
temperature

controlling
actual
or
set
body
temperature
with
the
desired
point
effectors
to
conserve
heat,
generate
heat
or
lose
heat.
body
temperature
effects on
°C
humans
The
body
increase
Figure
47
cells
damaged
4.1.1
44
temperature
heat
stroke
limit
body
of
normal
lower
34
temperature
beats
23
breathing
receptors
heart
of
normal
of
very
narrow
little.
temperature
Y
ou
limits.
can
change
see
outside
It
does
from
serious,
if
not
this
fatal.
This
is
an
example
mechanism
of
has
one
the
of
the
body ’s
following
homeostatic
components:
that
monitor
core
body
temperature
and
the
temperature
of
range

control

coordination
centre

effectors
systems
–
nervous
system
circulatory
system
and
hormonal
and
muscles
system
irregularly
in
the
skin,
to
bring
about
stops
stops
to
alter
the
temperature
of
the
body.
beating
body ’s
does
it
spinal
from
Effects of changes in body
temperature on humans
thermostat
have
flowing
100
effects
very
regulation fails
The
Figure 4.1.1
within
surroundings
changes
20
kept
temperature
36
25
is
fluctuates
range
the
limit
the
are
control
mechanisms.
upper
mean
range
T
emperature

37
that
but
regulation fails
42 fever
37
.6
temperature
decrease
permanently
narrow
45
core
and
its
own
through
cord
nerve
and
the
endings
of
useful
the
when
warning’
that
heat
and
loss
the
the
cells
but
organs
in
the
hypothalamus
that
it
skin.
starts
body
promote
to
the
Skin
and
get
in
the
the
information
temperature
this
lose
fall
conservation
is
from
of
in
if
heat.
body.
is
It
nothing
the
the
often
information
and
will
brain.
Not
temperature
temperature
cold
temperature
heat
monitor
receives
about
surroundings
body
the
in
brain,
other
temperature
is
nerve
only
the
nerves
blood
close
blood
in
and
to
the
also
the
particularly
acts
is
of
as
done
an
to
‘early
reduce
Module
If
the
temperature
is
less
than
the
set
point,
the
posterior
part
of
2
Biosystems
the
S tudy
hypothalamus
from
the
skin
instructs
surface.
the
skin
Muscles
to
in
conserve
the
heat
arterioles
by
in
diverting
the
skin
blood
contract
blood
supply
to
capillaries.
This
is
vasoconstriction.
If
this
to
fails
the
core
temperature
near
the
set
point,
the
posterior
to
the
body
to
produces
generate
heat.
The
heat.
rate
The
of
contraction
respiration
in
of
the
muscles
liver
this
heat.
heat
is
individual
Blood
then
hairs
flowing
through
distributed
to
trap
a
muscles
around
deeper
the
layer
and
body.
of
air
,
the
liver
Mammals
which
acts
is
warmed
with
as
about
of
the
homeostasis,
terms
a
set
point,
used
narrow
in
limits,
during
increases
receptors,
fur
effectors
and
learn
details
to
corrective
release
use
section:
monitor,
shivering
write
make
hypothalamus
this
instructs
you
to
try
keep
foc us
away
When
reduce
maintenance
action.
and
raise
the
good
S tudy
foc us
insulation.
The
are
effectors
to
take
‘correct’
actions
the
actual
that
are
level
of
called
the
corrective
physiological
actions
factor
as
so
their
that
it
effects
You
of
back
to
do
the
temperature
hypothalamus
the
need
to
the
temperature
control. We
have
normal.
used
If
not
goes
skin
is
more
instructs
surface
and
to
than
the
the
the
skin
to
sweat
set
point,
lose
heat,
glands.
the
by
anterior
part
diverting
Muscles
in
of
more
arterioles
as
a
principles
the
blood
to
it
good
of
example
of
the
homeostasis.
to
the
Summary q uestions
sweat
glands
allowing
and
more
the
blood
rest
of
the
skin
relax
flow
to
capillaries.
so
This
these
is
vessels
widen,
vasodilation.
1
The
hypothalamus
which
helps
Animals
to
seek
also
control
out
controls
heat
shade
or
the
way
in
conservation,
go
into
which
heat
burrows
mammals
loss
during
and
the
heat
behave,
gain.
hottest
parts
of
When
it
is
cold
they
curl
up,
reducing
the
body
surface
exposed
the
heat,
generate
heat
air
.
Humans
temperature
The
monitoring
make
have
and
and
adjustments
narrow
limits.
process
–
a
outside
this
a
since
variety
we
control
to
the
one
of
body
Maintaining
dynamic
of
don’t
–
behavioural
have
body
so
this
that
fur
we
responses
rely
temperature
that
the
core
homeostatic
never
stops.
If
on
to
carries
on
equilibrium
to
all
is
is
temperature
keep
the
time
kept
a
warm.
3
range,
cells
function
less
efciently.
State
the
Dene
fluctuates
at
all,
but
internal
and
external
changes
location
in
the
of
temperature
body.
the
terms
homeostasis,
negative feedback,
receptor,
effector
and
corrective
action.
continuous
fluctuates
Y
ou
will
and
body.
set point,
might
ask
Explain
always
why
homeostatic
control
why
of
it
the
to
within
4
narrow
in
that
heat
changing
clothes
temperature
lose
to
receptors
the
effectors
conserve
the
2
day.
Identify
body
temperature
is
a
dynamic
influence
process.
the
core
there
body
are
factor
temperature.
changes
has
to
that
fluctuate
Also
the
stimulate
in
order
control
effectors
for
the
to
system
make
control
does
not
corrective
system
to
work
unless
actions.
The
5
work.
Draw
to
the
show
Negative feedback
a feedback
the
one
in
what
loop,
Figure
4.
1.2,
happens
temperature
of
similar
to
when
the
blood
decreases.
The
control
negative
always
mechanism
feedback
for
because
counteract
the
body
the
change
temperature
responses
in
body
is
negative
stimulated
temperature.
by
A
feedback .
the
It
is
hypothalamus
negative
6
The
temperature
aeroplane
system
like
this
is
always
attempting
to
reduce
the
difference
between
cabin
body
temperature
and
the
ideal
temperature
or
set
point.
shows
how
negative
feedback
is
involved
in
controlling
person
when
The
the
blood
corrective
temperature
actions
can
be
increases
‘switched
as
off ’
it
does
when
of
returns
showing
how
to
normal.
this
The
control
feedback
loop
in
Figure
into
4.1.2
is
store
a
in
vasodilation
in
and
the
temperature
is
–18 °C.
in
the
Describe
changes
that
body
to
occur
keep
in
a
the
constant
normal
temperature.
blood
the
the
sweating
hypothalamus
nerve
nerve
impulses
impulses
hypothalamus
promote
heat
temperature
7
Make flow
blood
at
original
temperature
=
turns
to
off
corrective
chart
diagrams
loss
summarise
that
Figure 4.1.2
at
loss
thermoreceptors
centre
temperature
store
skin
heat
blood
cold
a
core
central
in
36 °C.
operates.
person’s
rise
is
aircraft
blood
the
way
landing
the
during
the
cold
temperature
on
leaves
airport. The
exercise.
air
body
walks
temperature
an
23 °C. The
Figure
A
4.1.2
is
the
temperature
actual
in
feedback
measures
negative feedback
occur
the
when
temperature
a
changes
the
body
increases,
and
b
decreases.
This feedback loop shows what happens when the temperature of the blood
increases, for example during exercise
101
4.2
Hormones
Learning outcomes
n
mammals
Cell
signalling
Communication
On
completion
of
this
section,
chemicals
should
be
able
dene
the
terms
hormone,
ductless (endocrine)
gland
and
target cell

identify
a
This
tends
to
for
some
electrical
impulses,
explain
of
the
the
how
coordination
section
of
activities
are

Cell
is

Did you know?

that
some
four
of
Cells
in
severe
contains
Nerve
is
known
name
which
and
used
you
in
is
a
long
to
are
communicate,
specialised
distances,
cells
allowing
although
that
quite
send
fast
chemical
is
communication
in
Chapter
using
hormones.
6.
in
which
cells
signal
to
each
by
cells
other
using
chemicals:
chemicals
is
area.
are
released
These
histamine
(see
glands
are
sometimes
page
secrete
to
influence
called
local
other
cells
hormones;
144).
hormones
into
the
blood
104).
endings
release
other
neurotransmitter
neurones
or
effectors
chemicals
such
as
at
synapses,
muscles
and
which
glands
(see
124).
Nerve
endings
page
release
hormones
into
the
blood;
this
is
neurosecretion
116).
may nd
paracrine
secretion
(b)
nerve
impulse
nor-adrenaline,
neurotransmitter
is
way
websites. A
compound,
hormone,
slow
Nerves
In
(a)
related
release
distant
as
(see
this
Cells
and
allergic
adrenaline.
adrenaline
epinephrine
electrical.
neighbouring
people

the USA,
a
over
nerves
ductless
page
page
reactions
by
immediate
stimulate
case
rather
often
ways
example
(see
TM
in
be
functions.
about
signalling
the
an
carry
and
other
in
in
EpiPen
of
hormones function
mammals.
The
chemical
ductless
There
in
is
activity
mammal
Communication

cells
the
communication.
some
of
influence
adequate
This
glands
to
to:
cells.

between
you
known
in
and
the USA
a
histamine
as
(c)
endocrine
secretion
nerve
nor-epinephrine.
target
cell
direction
cells
of
nerve
adrenaline
impulse
S tudy
Sending
energy;
foc us
nerve
impulses
sending
uses
hormones
blood
is
a
much
‘cheaper’
blood
is
circulating
in
much
the
option
as
(d)
concentrations
of
anyway
and
hormones
in
blood
the
neurosecretion
antidiuretic
the
neurotransmitter
hormone
blood
are
tiny
so few
molecules
need
acetylcholine
to
be
produced. That
signalling
via
the
makes
blood
chemical
muscle
energy
cell
another
efcient.
receptor
target
or
nerve
cell
cells
molecules
S tudy
Ductless
foc us
glands
are
Figure 4.2.1
also
known
as
This
endocrine
with
glands.
ducts
that
sweat
glands
These
are
glands.
Examples
you
and
will
know
salivary
examples
of
of
glands
are
glands.
exocrine
section
glands
Figure
and
that
is
are
4.2.1).
directly
into
carry
these
in
about
hormones,
transported
Ductless
the
the
information
of
102
Different methods of cell signalling
blood
glands
rather
secretion
about
Unit
1.
the
long
to
which
contain
than
another
main
are
distances
secreted
in
cells
that
secreting
place.
hormones
the
in
ductless
(see
secrete
them
The
by
blood
into
table
c
in
hormones
tubes,
or
ducts,
summarises
mammals.
Y
ou
studied
some
Module
Hormone
(chemical
Ductless
gland
Target
cells
2
Effects
nature)
antidiuretic
(peptide;
see
adrenaline
from
an
page
91)
insulin
page
hormone
page
posterior
cells
116)
adrenal
acid;
lining
the
convoluted
(derived
amino
pituitary
see
gland
(medulla)
distal
tubules
collecting
ducts
liver
cardiac
cells;
cells
in
the
in
stimulates
and
the
(protein;
see
pancreas
liver
cells;
tissue;
water
muscle
stimulates
heart
from
adipose
muscle
cells
in fat
heart
stimulates
cells
and
release
page
(protein;
liver
cells
are
hormones.
binds
compound
The
that
means
its
is
soluble
an
cannot
these
When
messenger
with
further
it
arrives
an
quickly
the
inactive
to
to
to
stimulates
target
for
the
to
as
cell
enzymes
out
cells.
to
the
synthesis
release
hormone
is
a
passes
steroid
hormone
through
the
that
is
not
phospholipid
of
glucose
liver
a
in
the
activate
signal
effect.
Calcium
many
animals.
ions
are
second
processes
See
page
in
messengers
plants
124 for
and
an
example.
so
This
message.
adrenaline
T
estosterone
glucose
Link
surface,
within
the
of
glycogen;
these
produce
‘signal’
amplify
carry
the
at
enzyme
taking
able
their
specically
enzymes
enzymes
respond
enter
cells
activates
interacts
activate
can
and
second
activated
cells
of
example.
receptor
a
and
surface
messenger
many
the
the
as
enzymes
are
that
to
acts
second
These
there
water
on
Adrenaline
adrenaline
them.
are
receptors
glucose
rate
uptake
storage
from
hormones
There
that
pancreas
104)
Some
cell.
see
of
liver;
stimulates fat
glucagon
of
kidney
increases
104)
reabsorption
water
bilayer
soluble.
and
in
the
blood
This
interacts
with
a
cell
receptor
inside
the
cytoplasm.
It
acts
to
activate
transcription
of
certain
genes.
of
Hormones
then
circulate
broken
molecules
urine
or
down.
that
do
broken
in
the
This
not
down
bloodstream,
happens
interact
in
the
within
with
liver
.
interact
their
target
The
with
target
cells
are
receptors
cells.
of
a
inactive
are
over
time.
concentration
very
short
in
The
the
half-lives
half-life
blood
(e.g.
to
of
a
hormone
decrease
adrenaline
by
a
is
half.
160–190
the
out
time
Some
in
longer
ones
(e.g.
testosterone
>
30
taken
hormones
seconds)
cell
enzyme
the
and
for
have
others
enzyme
its
ATP
cyclic AMP
have
Figure 4.2.2
much
liver
hormone
active
decreases
a
Hormone
passed
concentration
and
surface
membrane
minutes).
Adrenaline acts at the cell
surface membrane to stimulate the
formation of cAMP, which is a second
messenger. cAMP activates the rst of
Summary q uestions
several enzymes in a cascade that results
in very many enzymes becoming active to
1
Dene
2
Explain
the
the
ductless
of
a
terms
principles
glands
hormone
short
term,
hormone,
in
c
3
Explain
the
4
Explain
why ADH
5
Outline
6
Suggest
term
what
the
has
long
signalling
each
half-life
as
secretion
may
Include
of
by
in
break down glycogen.
target cell
using
your
the following
hormones
answer
effects:
at
a
secreted
least
one
by
example
instantaneous,
b
term.
happen
advantages
multicellular
cell
mammals.
that
and
of
ductless gland,
organisms.
of
applied
is
an
to
hormones.
example
when
a
using
chemical
of
hormone
neurosecretion.
arrives
at
a
target
communication
cell.
within
Figure 4.2.3
Adrenaline will be coursing
through the blood vessels of both horses
and riders at the start of this race
103
4.3
Regulaton
Learning outcomes
of
Blood
Our
On
completion
of
this
section,
be
able
state
that
blood
glucose
cells
but
within
the
in
roles
the
the
explain
blood
how
involved
supply
in
the
of
glucose
brain,
only
so
use
that
they
glucose
can
and
respire.
cannot
of
insulin
parts
of
the
body
work
together
to
supply
include:
digestive
the
system
–
digests
starch
to
glucose
and
absorbs
glucose
blood
and
the
endocrine
system
insulin
and
–
the
islets
glucagon
to
of
Langerhans
control
the
in
the
pancreas
concentration
of
glucose
glucose
negative feedback
with
Many
These
homeostatic
in

else.
glucose.
secrete
of
those
limits

control
constant
as
anything
with
into
glucagon
a
such
is

maintained
describe
require
cells,
to:
concentration fluctuates

concentraton
sugar
cells
respire

glucose
you
Some
should
blood
blood
the
blood
is

the
liver
and
muscles

the
circulatory
store
glucose
as
glycogen
glucose
system
–
transports
glucose,
insulin
and
glucagon
control.
dissolved
The
glucose
narrow
in
the
plasma.
concentration
limits.
It
is
not
in
the
blood
constant.
The
fluctuates
but
concentration
is
is
kept
within
usually
within
the
3
range
80–120 mg
glucose
per
blood
100 cm
and
is
normally
about
–3
90 mg 100 cm
.
glucose
ltered
in
the
that
urine.
is
If
it
This
rises
too
from
happens
high
the
if
then
blood
the
the
and
kidney
some
concentration
cannot
will
of
be
reabsorb
lost
glucose
from
in
the
all
the
the
body
blood
is
–3
above
urine
,
180 mg 100 cm
is
obviously
not
which
respired
is
the
or
renal
stored
threshold .
as
glycogen
Glucose
or
as
fat.
lost
If
in
the
the
–3
glucose
concentration
enough
for
When
Figure 4.3.1
the
the
brain
falls
cells
concentration
below
and
a
,
60 mg 100 cm
person
increases
may
above
enter
the
set
then
a
there
is
not
coma.
point:
Islet tissue is scattered
throughout the pancreas. The surrounding
1
β
cells
in
the
islets
of
Langerhans
act
as
glucose
detectors.
This
is
tissue produces enzymes, which are
because
they
have
protein
channels
in
their
enter
cells
cell
surface
membranes
secreted through the pancreatic duct into
that
let
glucose
molecules
the
as
the
concentration
rises.
the small intestine (× 175).
2
β
cells
secrete
glucose
in
released
enzyme-secreting
cells

the
into
insulin
blood.
the
as
in
(α
blood
glucose
acts
the
Insulin
circulates
response
cells
by
stop
liver
to
an
increasing
releasing
cells.)
The
concentration
glucagon
so
increasing
glucose
of
is
not
concentration
of
stimulus.
cell

cell
3
target
4
The
insulin
membrane
adipose
5
in
the
bloodstream
and
binds
to
insulin
receptors
on
cells.
Binding
receptor
of
the
is
a
target
transmembrane
cells,
which
are
protein
muscle
in
the
cells,
cell
liver
surface
cells
and
cells.
of
messenger
insulin
that
to
its
receptor
activates
target
blood
stimulates
cells
to
the
absorb
formation
and
use
of
a
second
glucose.
containing
glucagon
fall
normal
in
liver

blood
the
glucose
cells
in
blood
pancreas
glucose
gluconeogenesis
concentration
concentration
Figure 4.3.2
The α cells secrete
glucagon and the β cells secrete insulin
blood
into the capillaries within the islet. These
at
normal
glucose
concentration
turns
off
hormones are carried away via veins into
corrective
measure
=
negative
feedback
the hepatic portal vein that carries blood
directly into the liver.
104
Figure 4.3.3
This feedback loop shows how glucagon raises the blood glucose concentration
Module
Insulin
stimulates
muscle
cells
and
adipose
cells
to
insert
more
2
Biosystems
glucose
S tudy
transporter
to
increase
proteins
the
(GLUT
uptake
of
proteins)
glucose.
into
The
their
cell
enzymes
in
surface
glucose
to
glycogen
are
activated.
The
muscle
enzymes
cells
that
that
other
to
fat
are
activated
in
adipose
hormone
as
insulin
has
a
number
of
effects
on
liver
It
stimulates
of
more


the
glucokinase
GLUT
carriers
It
increases
It
stimulates
activating
increased
enzymes,
the
use
the
the
in
of
uptake
which
the
conversion
of
glucose
by
phosphorylates
for
of
example
glucose
glycogen
increasing
glucose,
the
not
activity
by
putting
See
It
inhibits
the
enzymes

It
inhibits
the
conversion
this
stored
activity
as
storage.
blood
results
glycogen
The
for
overall
in
that
of
fats
glucose
is
in
the
the
page
134 for
of failure
to
and/or
the
to
respond
secrete
to
it.
in
into
respiration.
glycogen
( glycogenesis )
Link
by
synthetase.
break
short-term
effect
glucose
insulin
down
glycogen
to
and
proteins
being
‘put
storage
that
the
or
into
away ’
described
in
1.4
of
1
in Unit
1.
glucose.
for
later
.
converted
concentration
is
glucose.
Module
All
of
consequences
Glycogen

same
membranes.
glucose,
enzyme
the
decreasing
cells:
blood.

in
cells.
concentration
Insulin
has
convert
effects
glucose
foc us
membranes
No
convert
maintenance
to
of
Glucose
fat
for
glucose
is
long-term
in
Link
the
decreases.
Read pages 115 and 117 to nd out
When
the
concentration
decreases
below
the
set
point.
about the reabsorption of glucose in
1
α
cells
in
the
islets
concentrations
cells
to
stop
of
of
Langerhans
glucose
secreting
by
respond
releasing
to
decreasing
glucagon.
They
the kidney and the simple test to show
also
stimulate
β
that glucose is present in urine. A
insulin.
positive result may indicate problems
2
Glucagon
receptors
3
The
circulates
on
liver
receptor
as
of
the
bloodstream
and
binds
to
glucagon
with blood glucose control that is not
cells.
interacts
concentration
effect
in
cyclic
adrenaline
in a homeostatic equilibrium.
with
other
AMP
(see
membrane
inside
page
liver
proteins
cells
and
to
this
increase
has
the
the
same
103).
Summary q uestions
Glucagon
has
these
effects
on
liver
cells:
1

It
stimulates
glycogenolysis
(literally:
splitting
glycogen)
by
Explain
why
glucose
the
enzymes
that
break
down
It
stimulates
the
conversion
concentration
of
in
the
blood
must
not
be
glycogen.
allowed

the
activating
of
fat
and
protein
into
to fall
too
low
or
rise
too
intermediate
high.
metabolites
that
are
converted
into
glucose
–
this
is
known
as
gluconeogenesis
These
liver
two
cells
processes
so
that
2
lead
glucose
to
an
increase
diffuses
out
in
into
the
the
concentration
blood.
The
of
glucose
glucose
in
the
blood
increases
and
this
keeps
cells
the
synthesis
in
supplied
with
Explain
Negative feedback
with
temperature
feedback.
and
β
The
cells
4
the
control,
concentration
monitor
If
the
the
this
of
method
blood
of
control
glucose
concentration
and
is
kept
respond
involves
within
when
it
negative
limits.
The
increases
concentration
of
glucose
rises,
then
insulin
is
to
a
lowering
of
the
concentration.
If
the
released
concentration
falls,
then
glucagon
is
released
by
α
cells,
leading
to
an
why
insulin
surface
α
by
the
of
insulin
control
of
and
the
of
Draw
This
maintains
the
homeostatic
are
receptors
glucagon
liver
on
the
cells.
loop
similar
to
one
in
Figure
4.3.3
to
show
of
increase
happens
when
the
blood
in
concentration
increases
equilibrium.
above
6
S tudy
there
and
a feedback
glucose
concentration.
concentration.
β
what
the
insulin.
and
the
leading
glucose
roles
in
glucose
Explain
for
5
decreases.
cells,
of
and
resource.
blood
As
sites
glucagon
a
glucagon
valuable
precise
of
concentration
3
of
State
the
Explain
set
why
point.
there
are
no
foc us
receptors for
glucagon
on
muscle
cells.
Show
axes
the fluctuations
on
glucose
graph
in
paper. The
blood
glucose
horizontal
concentration. Add
by
axis
is
some gures
drawing
time
to
a
and
your
sine
the
wave
on
vertical
vertical
a
axis
axis from
pair
is
of
blood
this
section.
7
Why
is
serious
insulin
deciency
medical
a
condition?
105
4.4
Plant
hormones
Communication
Learning outcomes
Unit
On
completion
should

be
able
dene
the
of
this
section,
you
1
you
cytokinins
ethylene,
to:
term
between
learnt
and
about
the
three
gibberellins.
which
is
also
different
parts
different
A
very
known
as
groups
different

describe
the
(ethene)
on
discuss
the
of
commercial
C
uses
of
Ethylene
is
a
is
small
diffuse
other
hormones
plant
growth
different
diffuses
out
into
plants
are
also
substances
known
and
auxins,
hormone
is
in
that
from
is
the
other
volatile
through
the
H
air
and
spaces,
atmosphere.
vicinity.
plant
forms
a
are
other
no
regulators
gas
influences
Unlike
There
growth
almost
its
PGRs,
other
as
target
it
similar
(PGRs).
soon
cells
has
as
and
effects
It
it
is
may
on
compounds
regulators.
In
this
that
as
a
like
or
effects.
ripening
section,
has
effects
on
growth,
ageing,
leaf
fall
and
cell
death.
The
only
plant
role
regulator
similar
as
Ethylene
described
have
plant
Fruit
growth
hormones:
plant
In
foc us
Plant
is
quite
molecule
It
ethylene
ethylene
of
chemicals.
C
H
of fruits
formed.
growth
plant
type
by
H
ethylene
ripening
ethylene.
S tudy
of
is
plant regulator
effects
the
plants
ethene:
H

of
simply
as
of
ethylene
that
you
need
to
from
Unit
1
know
about
is
its
effects
on
fruit
a
ripening.
regulator
molecule.
Y
ou
will
remember
containing
dispersed.
the
ripening
illustrate

seeds.
Fruits
Ethylene
of
the
Unripe
fleshy
tomatoes
in
fruits.
changes
synthesising
protect
helps
that
are
that
the
the
fruits
seeds
are
until
coordination
The
effects
fertilised
of
they
of
are
the
ovaries
ready
to
processes
ethylene
on
be
involved
tomatoes
in
will
happen.
green.
chlorophyll
At
and
the
start
start
of
ripening
producing
the
they
red
stop
pigment,
lycopene.

Enzymes

V
olatile
convert
characteristic
Figure 4.4.1
Many forest trees produce

Enzymes
succulent fruits that are eaten by monkeys
starch
chemicals
together
are
organic
acids
that
give
to
sugars.
ripe
tomatoes
their
smell.
hydrolyse
and
and
produced
once
pectins
broken
in
cell
down,
walls.
the
Pectins
fruits
hold
become
cellulose
much
bres
softer
.
that disperse the seeds, either by throwing
them away or passing them through their
These
changes
which
in
are
all
stimulated
by
ethylene,
which
stimulates
ripening,
guts. The simultaneous ripening of many
turn
triggers
even
more
ethylene
production.
This
is
an
example
fruits attracts monkeys like this Capuchin
monkey, Cebus
capucinus, in Nicaragua.
of
a
positive
production
effects
Did you know?
why
Polygalacturonidase
is
the
enzyme
In
a
of
hydrolyses
pectins
in
cell
some
engineers
ethylene
that
did
a
the
that
not
express
to
there
which
events
rise
attract
stimulate
the
to
a
climax
animals
enzymes
that
that
–
eat
in
this
them.
produce
it,
case
One
the
of
which
the
is
occurs.
is
a
and
steep
rapid
increase
increase
in
in
ethylene
the
rate
production
of
that
respiration
stage
of
ripening.
This
rapid
increase
in
just
respiration
is
climacteric
codes for
this
resulting
‘non-squashy’
were
very
and
banana,
avocado
and
tomato
are
examples
of
the
fr uits.
The
climacteric
is
the
time
when
these
fr uits
have
enzyme. The
the
best
taste
and
texture.
Figure
4.5.3
on
page
109
shows
the
changes
tomatoes
in
not
is
sudden
 nal
climacteric
gene
fruits,
feedback
fr uits,
which
produced GM
the
tomatoes
ripe
in
walls.
before
Genetic
of
positive
stimulates
that
feedback
successful
in
ethylene
concentration
and
rate
of
respiration
in
banana
during
the UK
ripening.
because
–
even
tomato
106
of fears
the
use
paste.
about GM food
of GM
tomatoes
in
Since
fruit
it
is
a
nearby.
gas,
ethylene
released
by
one
ripening
fruit
influences
other
Module
Not
all
fleshy
fruits
are
climacteric;
examples
are
citrus
fruits
and
2
Biosystems
grapes,
S tudy
which
release
ethylene,
but
without
it
triggering
the
rapid
rise
maintenance
foc us
in
respiration.
You
can
carry
out
a
controlled
–3
Ethylene
By
is
active
comparison,
greater
.
trigger
An
at
the
apple
ripening
very
concentrations,
concentration
that
in
low
has
begun
surrounding
inside
to
an
ripen
apples
as
little
apple
releases
and
the
as
may
1 ppm
be
2500
ethylene
whole
lot
times
that
may
experiment
).
(1 µl dm
in
will
go
and
sold.
such
the
as
Apples
summer
or
long-ter m
want
any
apples
by
cold
the
the
grow
their
and
of
air
fr uit
throughout
the
for
sale
the
that
the
over
to
the
next
dioxide
dioxide.
carbon
dioxide
year.
crisp
Carbon
are
put
10
can
dioxide
of
the
some
happens
over
you
a
ripe
unripe
to
banana
tomatoes.
the
time. What
control
use?
or
the
be
They
to
the
be
into
do
keep
store
removes
to
late
apples
they
for mation
sent
inhibits
so.
so
times
going
in
their
apple
fl ow
at
are
har vested
ethylene,
air
ripen
they
months
inhibits
apples
all
many
through
The
can
where
and
producing
carbon
 r m,
apples,
places
Growers
start
carbon
and
the
climates
autumn.
apples
fl ush
and
near
temperate
3–5%
so
tomatoes
nowhere
in
storage
atmosphere
from
are
during
of
what
putting
applications
bananas,
fr uits
with
tomatoes
would
Commercial
when
bag
Watch
soft
inedible.
Fr uits,
a
by
to
not
the
give
an
ethylene
of
ethylene
markets
enzyme
that
produces
ethylene.
Figure 4.4.2
Bananas
are
picked
when
they
are
still
green
and
unripe.
They
are
Harvesting bananas. Fruits
then
that are to be shipped overseas are picked
shipped
in
damaged
containers
by
chilling
refrigeration
ethylene
at
board
which
with
that
is
ship,
uses
a
the
may
and
any
again,
this
to
the
to
kept
17 °C
sodium
the
risk
convert
which
fruit
Any
does
bananas
or
lower
not
into
potassium
bananas
of
for
24
sealed
for
may
hours.
The
that
about
reach
in
3
to
and
taste
plastic
bananas
good.
bags
manganate(
the
is
ripened
the
or
kept
air
are
green and packaged into plastic bags that
are carefully labelled.
Where
with
VII)
4
higher
then
days
by
at
for
an
and
The
an
to
The
fruit
the
The
100
an
is
ethylene,
mixed
generator
are
to
range
the
then
occur
.
30
to
is
1000 ppm
accidental
is
packed
ethylene
and
remove
room
ripening
in
using
ethylene
17 °C.
vented
temperatures
by
sometimes
between
accumulated.
or
gas,
ethylene.
and
Any
room
has
of
explosion,
ethanol
is
are
canisters
concentration
dioxide
fruit
13.3 °C.
ripe
packing
from
the
explosion.
at
the
a
sealed
an
as
at
the
ripening.
reduce
to
kept
and
arrival,
room,
carbon
time
on
give
room
cause
such
introduced
catalyst
into
introduced
and
or
either
are
available,
preventing
nitrogen
tightly
not
absorbent,
effective
On
is
that
injury
spark
ethylene
closed
During
40 °C
and
Figure 4.4.3
they
from
release
the
large
quantities
of
carbon
dioxide,
which
must
be
vented
Bananas packed in plastic
bags for sale in a supermarket in the UK
store.
Summary q uestions
1
Explain
ripen
the
as
advantages for
described
on
the
plants
of
opposite
having fruit
that
4
page.
Explain
and
2
Suggest
release
the
advantages
ethylene
as
they
of
trees
having fruits
Suggest
5
ripen.
the
require
Avocado
be
airtight,
refrigeration
rooms
yet
and
have
in
temperate
good
heating
ventilation,
equipment.
start
pears
are
ripening
climacteric fruits,
until
after
they
yet
they
do
have fallen from
why:
the
a
banana-ripening
must
that
not
3
why
countries
temperature
of
bananas
increases
tree.
Suggest
what
prevents
avocados
ripening
during
before
they fall from
the
tree.
Explain
how
you
might
ripening
encourage
b
carbon
dioxide
ripening
must
be
vented from
avocados
to
ripen.
banana-
stores.
107
4.5
Practce
exam-style
questons:
Homeostass
Answers to
1
a
b
all
Dene
the
Outlne
blood
c
exam-style questions
term
the
role
can
be found on the
homeostasis.
of
the
ler
[2]
n
the
control
the
3
of
ways
n
whch
cells
chart
pathways
carbohydrate
[3]
dfferent
The flow
the
glucose.
Descrbe
accompanying CD.
n
Fgure
noled
n
the
4.5.2
n
the
human
shows
some
metabolsm
of
of
body.
sgnal
carbohydrate
to
2
each
Thyroxne
other.
s
a
[6]
hormone
secreted
by
the
in food
thyrod
A
gland,
whch
thyroxne
body.
s
s
to
a
ductless
ncrease
gland. One
the
Negate feedback
of
producton
s
noled
n
the
of
roles
heat
the
of
by
the
control
glucose
of
in
blood
thyroxne.
B
a
Explan
why
the
thyrod
gland
s
a
gland.
the
chart
release
of
n
Fgure
thyroxne
4.5.
1
by
shows
the
the
anteror
control
of
in
J
acids
glucose
liver
in
and
the
glucose
liver
muscle
in
tissue
ptutary
D
gland
F
[1]
amino
The flow
C
ductless
E
H
G
hypothalamus.
glycogen
hypothalamus
in
TRH
anterior
pituitary
a
State
each
TSH
thyroid
muscle
in
tissue
Figure 4.5.2
gland
heat
glycogen
liver
the
of
letter
or
letters,
A
to
J,
that
ndcates
the followng:
i
glycogeness
[1]
ii
glycogenolyss
[1]
iii
gluconeogeness
iv
processes
promoted
by
nsuln
v
processes
promoted
by
glucagon.
gland
[1]
thyroxine
thyroxine
[1]
[1]
body
b
TRH
=
thyrotropin
TSH
=
thyroid
releasing
stimulating
c
Explan
to
there
arrow
why
t
concentraton
4
the
why
drecton
hormone
hormone
Figure 4.5.1
Use
Explan
nformaton
aboe
to
answer
Insuln
and
s
s
no
arrow
glucagon
the
opposte
F.
[1]
mportant
of
n
blood
hae
to
regulate
the
glucose.
[4]
antagonistic effects
to
the followng
mantan
the
homeostatic eq uilibrium
for
blood
questons
glucose. Ths
b
State
what
wll
happen
to
the
secreton
s
a
dynamic process
that
s
acheed
by
of
negative feedback.
thyroxne
nto
the
blood
f:
a
i
the
secreton
of TSH
ncreases
Explan
the
ii
the
secreton
of TRH
decreases
context
the
producton
i
State
of
heat
ncreases
greatly.
a
target
organ for
n
the
thyroxne.
The
half-lfe
of
thyroxne
s
about
7
the
term
half-life
as
the
of
terms
the
n
talcs
n
concentraton
appled
blood.
of
[4]
Explan fully
how
nsuln
and
equlbrum for
glucagon
blood
mantan
glucose.
a
[6]
days.
c
Explan
by
control
[1]
homeostatc
ii
meant
the
[1]
b
c
s
of
[1]
glucose
iii
what
[1]
Explan how the acton of the plant growth
to
regulator ethylene dffers from the acton of
hormones.
[1]
anmal hormones, such as nsuln and glucagon.
d
TRH s a neuropeptde. Explan what ths means.
e
Explan
how
secreton
108
of
negate feedback
thyroxne.
s
noled
n
[2]
the
[3]
[2]
Module
table
nsuln
lfe
of
n
a
shows
the
the
blood
concentratons
plasma
at
of
glucose
dfferent
tmes
and
n
7
Fgure
shows
and
the
the
rate
changes
of
n
concentraton
respraton
n
a
teenager.
140
h
1–
g
1–
Insulin
120
concentration
in the
in the
plasma/
OC l
2
concentration
plasma/
prolonged
100 cm
arbitrary
60
respiration
=
ethylene
25
20
100
units
noitaripser
mg
=
/
–3
6
starvation
80
15
60
10
40
fo
an
80
etar
during
of
banana frut.
30
Glucose
during
4.5.3
ethylene
the
maintenance
9
overnight fast
enelyhte
The
Biosystems
mpp/noitartnecnoc
5
2
5
20
0
1
after
a
large
160
2
3
4
5
6
7
8
9
10
70
time
after
harvest/days
breakfast
Figure 4.5.3
after
the
70
absorption
meal
a
is
of
a
10
b
complete
Descrbe
Descrbe
the
the
relatonshp
between
i
concentratons
of
glucose
and
State
the
fruts
as
gen
Explan
the
n
the
nsuln
n
the
changes
n
the
Outlne
the
and
nsuln
n
the
concentratons
when
t
s
Dscuss
blood
durng
a
Explan
the
absorbed.
low
Use
concentratons
of
nsuln
s
terms
controlled:
the
set
pont,
n
to
explan
how
stmulus,
s
the
a
plant
correcte
acton
Durng
when
the
conerted
rpenng
to
ethylene
a
descrbed.
[3]
s
used
to
prode frut
of
[3]
hormone
of
whch
the
4.5.4
at
that
s
produced
secreted
danger. One
by
of
the
ts
adrenal
target
t
stmulates
to
release
organs
glucose
term
hormone.
[2]
shows
the
what
surface
of
happens
a
ler
when
cell
wth
adrenalne
the
of
the
second
messenger,
cyclc AMP.
by
rpen.
in
the
blood
enzyme
process
reducng
hae
[7]
regulator
they
you
and
adrenaline
bananas
the
blood.
Dene
producton
s
controllng
receptors,
negate feedback.
Ethylene
n
blood
arres
6
[4]
ethylene
qualty.
tmes
ler,
Fgure
effectors,
of
[3]
a
glucose
clmacterc
durng
and fastng.
the followng
n
rpen.
role
that
how
Adrenalne
nto
d
occur
[3]
[5]
s
staraton
ethylene
meal
medulla
c
the
respraton.
of
8
and
that
of
[2]
marketable
glucose
between
rate
blood
table.
c
b
the
changes
they
changes
as
and
the
ii
plasma
relatonshp
concentraton
a
n
bananas
starch
s
cell
of
sugars.
surface
a
liver
membrane
cell
enzyme
a
Outlne how you would nestgate the change n
carbohydrate content n bananas as they rpen.
b
Bananas
are
clmacterc fruts.
Explan
the
[5]
term
ATP
climacteric.
Potassum
ethylene
c
manganate
to
Explan
preent
how
an
(vii)
s
used
bananas from
ethylene
as
an
absorbent
rpenng.
absorbent,
such
activates
of
manganate
(vii),
preents
enymes
in the
cytoplasm
Figure 4.5.4
as
b
potassum
cyclic AMP
[1]
Explan why adrenalne does not enter the ler cell.
bananas
[2]
from
rpenng.
[1]
c
d
Outlne
and
the
anmal
dfferences
hormones.
between
plant
regulators
Use
Fgure
adrenalne
4.5.4
to
arres
descrbe
at
the
what
surface
happens
of
the
when
ler
cell.
[2]
[3]
d
Explan
the
role
of
a
second
messenger,
such
cyclc AMP.
e
Descrbe
the
f
the
as
[2]
response
producton
of
of
the
ler
cell followng
cyclc AMP.
[2]
Adrenalne stmulates arteroles n the gut and skn
to constrct. Explan the adantage of ths.
[4]
109
2
Biosystems
5.
1
Excretion
maintenance
Excretion
Learning outcomes
products
On
completion
should
be

dene

list
able
the
of
this
section,
you
term
of
are
removal
metabolism
The
produced
and
table
and
from
body
substances
lists
the
the
the
of
toxic
that
excretory
metabolic
substances,
are
in
excess
products
processes
that
in
the
waste
of
mammals,
make
where
them.
excretion
Excretory
the
the
requirements.
they
to:
is
excretory
products
product
Site of
production
Metabolic
process
in
carbon
mammals
dioxide
all
respiring
cells
aerobic respiration:
decarboxylation in the link

explain
why
excretory
products
reaction and Krebs cycle
must
be
removed from
the
body
(see page 26)

outline
the
produces

describe
the
process
which
urea
the
kidney:
gross
structure
external
and
ammonia
liver
deamination
urea
liver
urea
of
the
vertical
cycle
(also
known
as
in
ornithine
cycle)
section.
uric
acid
liver
purine
metabolism
(breakdown
S tudy
and
foc us
guanine
and from
Remember the denition of
of
adenine
in
the
nucleic
diet
acids
and
nucleotides)
metabolism from Unit 1: all the
bile
pigments
liver
breakdown
of
haem from
chemical reactions that occur in
(biliverdin
and
bilirubin)
haemoglobin
organisms. The most important of
these is respiration; in this section you
These
excretory
substances
have
various
effects
on
the
body
if
allowed
to
see that deamination and the reactions
accumulate:
that produce urea are also important

in producing metabolic waste.

Acidosis
is
normal

The
cytosol
cytoplasm
is
the
that
organelles.
It
is
part
of
the
surrounds
where
all
range.
place
(see
page
blood;
increases
such
as
caused
cells
the
are
pH
in
respiration
by
high
concentrations
damaged
if
blood
cytoplasm;
and
with
it
pH
of
falls
interferes
receptors
for
carbon
below
with
the
metabolic
neurotransmitters
brain.
is
highly
diffusible
potential
cytoplasm
very
so
that
and
passes
water
is
into
cells;
absorbed
by
this
decreases
osmosis,
their
making
the
‘watery ’.
glycolysis

takes
the
Urea
water
the
the
Ammonia
in
foc us
condition
in
processes
S tudy
a
dioxide
Uric
acid
can
form
crystals
in
joints,
causing
a
form
of
arthritis
called
22).
gout,

Bile
which
causes
R
Urea
H
an
is
pigments
a
very
–
painful.
accumulation
yellowish
appearance
in
the
skin
known
as
and
other
areas
of
the
body
jaundice.
production
amino
COOH
Excess
amino
acids
cannot
be
stored;
they
are
a
good
source
of
energy
,
but
acid
the
group
–NH
has
to
be
removed
before
they
are
respired.
Once
this
is
2
H
R
removed,
the
rest
of
the
molecule
is
an
organic
acid,
similar
to
those
in
the
an
Krebs
cycle.
The
group
–NH
immediately
forms
ammonia
and
the
2
COOH
NH
organic
3
ammonium
ion.
This
is
highly
toxic,
so
is
converted
to
urea.
The
process
by
acid
ammonia
Figure 5.1.1
110
H
Deamination of an amino acid
which
and
this
partly
happens
in
the
is
a
cycle
cytosol.
of
This
reactions
cycle
is
that
shown
occurs
in
partly
outline
in
in
mitochondria
Figure
5.1.1.
Module
2
NH
Krebs
maintenance
Link
3
from
Biosystems
cycle
CO
2
and
link
reaction
See Question
7 on
page
119 for
an
2ATP
example of
O
O
a
blood-eating
animal
2ADP
that
H
C
N
O
P
produces
large quantities of
urea.
(1N)
O
2
carbamyl
phosphate
–
O
ornithine
P
(2N)
citrulline
(3N)
O
ornithine
cycle
C
H
2
NH
2
urea
(1N)
2
from
(2N)
(an
H
arginine
O
aspartic
amino
acid
acid)
(4N)
2
Figure 5.1.2
Urea is synthesised in liver cells from ammonia and carbon dioxide by a cycle
of reactions. The numbers refer to the number of nitrogen atoms in each compound.
This
to
cycle
uses
produce
Urea
the
diffuses
hepatic
production
tigers
The
and
amino
little
be
in
a
other
who
than
are
proteins
to
are
nitrogen
are
a
cavity
of
from
see
the
as
of
a
a
is
of
is
diet,
are
their
a
acids
less
In
of
nitrogen
nitrogen
in
to
are
acids,
External view of the kidney
of a lamb showing the renal vein, renal
artery and ureter
people
muscle
the
they
Figure 5.1.3
to
in
contrast,
and
life.
said
nitrogen
balance
protein
of
give
amino
energy;
deaminated
negative
its
lions,
way
diets
people
diet.
source
in
as
acids.
excess
excreting
in
as
little
away
such
people’s
These
dioxide,
A
TP
.
uctuates
amino
by
carbon
of
carried
blood
high-protein
excrete.
tissue
than
and
the
lot
There
they
a
in
and
form
high-protein
eat
proteins
in
the
inuenced
to
amino
organic
and
are
are
eating.
excretory organ
bean-shaped
the
with
organs
diaphragm.
the
surrounding
different
as
in
urea
below
kidney
the
urea
are
main
pair
just
a
proteins.
the
people
is
often
muscle
down,
These
eat
ions
in
blood
urea
deaminate
balance
using
the
of
daily
little
energy
into
that
muscle
muscle
and
are the
view
dissected
can
produced
consuming
are
broken
kidneys
Animals
building
are
cells
concentration
nitrogen
more
abdominal
liver
ammonium
require
carnivores,
make
they
Kidneys
Figure
the
urea
starving
excreting
Y
ou
of
respired.
external
top
are
positive
who
The
of
The
deamination
urea
acids
out
products:
reactions
uctuates.
acids
so
waste
The
vein.
quantity
Athletes
two
urea.
renal
vein,
connective
regions
of
the
situated
Figure
renal
tissue
kidney
in
the
fat
back
shows
artery
and
a
at
5.1.3
and
of
the
an
ureter
tissue.
vertical
section
as
in
Figure 5.1.4
5.1.4.
An internal view showing the
cortex, medulla, pelvis and ureter
Summary q uestions
1
Dene
2
List
the
term
6
excretion
Explain:
i
the
excretory
products
in
mammals.
State
why
rates
higher
and
where
each
product
is
Explain
from
why
the
excretory
products
need
to
be
5
Outline
what
happens
during
Explain
how
urea
is
be
in
produced
and
list
the
production
are
in
the
some
mammalian
quantity
day
to
of
urea
species
excreted
than
others
may uctuate
day.
which
it
travels from
why
a
bodybuilders
positive
and
nitrogen
elite
athletes
are
likely
balance.
Make
drawings
site
of
of
the
external
view
and
the
vertical
structures
section
production
to
of
the
kidney from
Figures
5.
1.3
and
5.
1.4.
site
Label fully
of
urea
deamination.
8
through
and
body.
to
Explain
why
from
removed
7
4
deamination
made.
ii
3
of
how
and
annotate
with
the functions
of
each
excretion.
structure
and
region
labelled.
111
5.2
The
kidney
In
Learning outcomes
nephron
4.3
two
On
completion
should

be
state
able
that
draw
and
this
section,
you
nephron
unit
of
the
describe
is

a
hormones
The
and
into
the
pelvis
in
cortex,
medulla
sections
insulin
The
The
islets
and
islets
are
functional
of
Langerhans
glucagon
–
functional
unit
of
the
in
that
the
pancreas
control
units
kidney
as
is
blood
each
the
one
secrete
the
glucose
performs
these
nephron.
nephron
structure
nephron
recognise
–
the
the
kidney
the
that
concentration.
Each
of
saw
functions.
to:
the
functional

of
we
of
the
nephron
a
Each
consists
collecting
nephron
glomer ulus;
is
duct
of
a
that
lined
collects
associated
surrounding
tube
with
each
a
by
urine
tight
nephron
a
simple
from
knot
are
a
epithelium
number
of
of
capillaries
many
more
that
drains
nephrons.
known
as
a
capillaries.
kidney
branch

recognise
the
parts
of
a
of
renal
artery
efferent
arteriole
nephron
glomerulus
afferent
in
sections
of
the
kidney
arteriole

draw
sections
of
the
kidney from
distal
convoluted
Bowman’s
the
tubule
microscope.
capsule
cortex

describe
the
appearance
of
the
branch
regions
of
a
of
nephron.
renal
collecting
vein
thick
duct
region
ascending
proximal
S tudy
of
limb
of
convoluted
foc us
loop
of
Henle
vasa
recta
tubule
You
should
be
able
to
make
a
medulla
descending
labelled
diagram
of
a
nephron
of
this
one from
limb
like
loop
of
Henle
thin
memory.
region
ascending
‘hairpin
bed’
of
of
loop
Did you know?
of
of
limb
loop
of
Henle
Henle
tissue
urine
to
pelvis,
ureter
fluid
and
The
total
length
of
the
in
your
body
is
bladder
kidney
Figure 5.2.1
tubules
then
about
A kidney nephron with associated blood vessels. The flow of blood is shown
80 km.
with solid arrows; flow of filtrate and urine with open arrows.
glomerulus
lumen
of
Bowman’s
distal
capsule
convoluted
tubule
(no
border
of
brush
microvilli)
proximal
convoluted tubule
(with
of
brush
border
microvilli)
glomerulus
Figure 5.2.2
A glomerulus surrounded by
capillary
the Bowman’s capsule (white space) and
sections of proximal and distal convoluted
tubules (× 300)
112
Figure 5.2.3
Drawing of part of the
section shown in Figure 5.2.2
Module
capillaries
the
vasa
loop
of
2
Biosystems
maintenance
of
recta
Henle
(thick)
nucleus
collecting
loop
of
duct
Henle
(thin)
Figure 5.2.4
Figure 5.2.5
A cross-section through the
Drawing of a section through the medulla showing some loops, collecting
ducts and capillaries
medulla of the kidney showing loops of
Henle and collecting ducts (× 600)
Y
ou
may
be
expected
photographs
and
to
study
drawings
microscope
should
help
slides
you
to
of
kidney
interpret
tissue.
what
The
you
see.
S tudy
Features
light

of
the
different
regions
of
the
nephron
that
can
be
seen
with
Search for
microscope:
Glomerulus
are
large
–
cells
capillaries
known
as
containing
podocytes
red
blood
which
cells;
have
in
between
prominent
foc us
the
some
micrographs
of
and
you
the
glomerulus
is
a
white
space
which
is
the
DCTs
so
this
capsule
is
surrounded
by
squamous
have
PCTs
an
nuclei;
of
the
three-
Bowman’s
dimensional
capsule;
electron
glomeruli,
there
appreciation
around
scanning
the
epithelium.
structure
of
the
Figure
nephron.
5.2.6

is
a
drawing
of
scanning
electron
Proximal
convoluted
made
of
made
up
a
glomerular
capillary
and
a
podocyte
made
from
micrographs
cuboidal
tubules
epithelial
(PCT)
cells;
–
cross-sections
cells
are
lined
by
are
a
near
brush
circular;
border
basement
of
many
membrane
microvilli.
endothelial

Loops
of
Henle
–
cross-sections
are
circular;
thin
sections
of
loops
cells
have
thin
squamous
epithelium;
thick
sections
of
loops
have
of
blood
thicker
,
capillary
cuboidal

Distal
epithelium;
convoluted
no
brush
tubules
border
.
(DCT)
–
Surrounded
cross-sections
by
are
many
capillaries.
circular
but
not
podocyte
as
wide
as
the
PCT
.
Cuboidal
epithelium
without
a
brush
border
.
cell
foot-like

Collecting
ducts
(CD)
–
cross-sections
are
wider
than
those
of
other
process
parts
of
the
nephron.
Cuboidal
epithelium
without
any
brush
circular
Summary q uestions
pores
endothelial
Figure 5.2.6
1
Explain
what
is
meant
by
the
term
functional unit
as
applied
to
of
podocyte
border
.
between
cells
A small part of a capillary in
organs,
a glomerulus with surrounding podocytes
such
2
as
Make
duct
a
the
kidney.
large
and
labelled
associated
diagram
blood
of
a
nephron
vessels. Add
to
with
your
a
glomerulus,
diagram
collecting
drawings
of
cross-
S tudy
sections
of
boundary
the
PCT,
between
loop
the
of
Henle,
cortex
and
DCT
the
and
collecting
duct.
Show
medulla.
Put
3
Write
4
Find
a
description
of
the
structure
of
foc us
the
the
nephron.
the ngers
between
of
hand. The ngers
more
photographs
of
sections
through
the
kidney;
print
them
out
you
have
now
left
hand
your
in
right
a
model
interdigitate
of
the
them fully.
projections
5
of
and
and
label
your
the ngers
Name
the
parts
of
the
nephron
in
a
the
cortex,
and
b
the
medulla.
you
can
see
of
in
the
podocytes
Figure
that
5.2.6.
113
5.3
The
excretory functions
The
Learning outcomes
kidney
useful
On
completion
should
be
able
of
this
section,
you
that
state
that
excretory
the
kidney
is
the
complex
The
the
such
waste
as
system
excretory
everything
includes
substances

a
substances.
principle
This
to:
has
of
below
for
ions
in
certain
that
and
kidney
ltering
system
a
products
glucose,
the
blood
mammals
size
are
the
to
amino
is
reabsorbing
operates
ltered
be
and
from
excreted
on
the
and
the
blood.
useful
acids.
main
organ
Ultrafiltration

explain
the
how
kidney
blood
and
is ltered
explain
how
glomerulus
and
capsule
adapted for
are
in
the
Blood
ows
occurs
Bowman’s
efcient
in
into
all
the
glomerulus
capillaries,
but
the
at
high
pressure.
glomerulus
is
Pressure
adapted
for
filtration
efcient
ltration.
ltration


describe
selective
Blood
head

outline
the
processes
the formation
of
involved
pressure
arterioles
reabsorption
of

The

pressure
capillaries
in
each
need
a
diagram
of
you
read
this
notes
in
to
the
diagram
that
on
answer
page
The
to
Summary
is
sometimes
excretory
only
is
a
acts
mass
capsule.
by
form
described
The
which
efferent
builds
up
a
pores
in
their
walls
that
are
at
least
basement
like
a
membrane
mesh
to
allow
that
is
made
everything
of
with
(RMM)
This
is
the
of
less
only
than
barrier
69 000
through
a
between
blood
into
and
the
the
accumulates
in
the
Bowman’s
capsule.
capillaries
podocytes,
are
cells
suspended
with
within
projections
that
the
do
Bowman’s
not
lining
around
the
capillaries.
Instead
the
form
cells
a
interdigitate
are
organ. Urea
present
because
lose
it
is
in
and
sodium
sweat,
but
of
to
heat,
those
substances.
not
to
the
excrete
to
The
enlarge
carrier
the
of
cells
is
of
from
Figure
5.2.6
reabsorbed
the
and
of
region
ltrate
to
membrane
surface
one
area
that
the
for
changes
facilitated
this
the
surface
cytoplasm
molecule
in
cell.
a
on
the
the
page
113.)
proximal
blood.
the
are
convoluted
adapted
Figure
lumen
and
carrier
ion.
move
The
tubule
absorption.
Each
to
the
glucose
sodium
shape
of
lining
for
move
diffusion.
5.3.1
of
This
tubule
them
absorption
they
into
shows
one
of
of
these
PCT
has
microvilli
has
many
molecule
When
movement
membrane
sodium
the
for
ions
has
are
the
from
two
both
the
sites
full
on
the
–
the
cytoplasm.
depends
ltrate
one
to
for
carrier
This
is
existence
a
of
form
a
foc us
concentration
The ltrate
(See
reabsorption
molecules
glucose
S tudy
pores.
ltrate
The
substances
cells.
made from ltered
blood
slit
as
(PCT).
chloride
and
glomerular
Selective
foc us
Most
an
heart.
113.
S tudy
skin
the
question
to
The
near
arterioles,
you
complete
2
are
afferent
glomerulus.
numerous
capillary
molecular
that
capsule
drew
the
kidneys
the
section.

Add
the
than
the
ltrate
as
as
foc us
Bowman’s
will
in
have
proteins
relative
nephron
high
diameter
.
Around
brous
You
is
narrower
in
urine.
4 nm
S tudy
are
has
composition
as
the
same
tissue uid
82). Try Question
lateral
2
to
test
(see
and
of
for
sodium
membranes
concentration
gradient
into
concentration
gradient
for
move
the
ions.
Sodium
sodium
tissue
ions
uid.
pump
proteins
against
This
in
the
their
provides
the
page
absorption
of
sodium
ions
and
glucose
at
the
your
luminal
understanding
gradient
basal
surface.
The
sodium
potassium
pump
proteins
require
A
TP
,
this.
which
is
supplied
Selective
by
the
reabsorption
many
mitochondria
involves
movement
in
each
through
cell.
the
PCT
the
upper
cells.
The
Link
cells
are
cells.
Look
at
the
data
on
the
attached
These
blood
plasma, ltrate
Question
reading
the
5
the
on
page
next
answers
to
119
and
urine
a
and
b.
of
Reabsorption
about
As
more
ltrate
be
114
‘sticky
tight
strips’
junctions
that
hold
around
the
cells
together
part
and
of
the
prevent
uid
between
cells
from
the
lumen
of
the
PCT
into
the
blood.
in
before
section. Think
parts
like
by
composition
movement
of
are
together
by
and
and
continues
more
blood
active
is
until
all
removed,
becomes
transport.
the
the
steeper
.
glucose
is
removed
concentration
This
explains
from
gradient
why
the
ltrate.
between
movement
has
to
Module
lumen
of
2
microvilli
PCT
S tudy
tight
The
junction
absorption
example
of
transport
rough
foc us
of
glucose
secondary
in
that
the
is
an
active
movement
endoplasmic
needs
energy,
but
the
gradient
is
reticulum
provided
by
something
ions. The
mitochondrion
lateral
pump
else,
this
pumping
of
case
sodium
sodium
and
membrane
potassium
ions
is
transport. These
cleft
proteins for
in
in
basal
called
indirect
primary active
are
and
sometimes
direct
active
basement
membrane
transport.
membrane
basal
Figure 5.3.1
membrane
A cell from the proximal convoluted tubule, showing how it is adapted for
selective reabsorption
The
luminal
membranes
of
PCT
cells
also
have
carrier
proteins
for
the
S tudy
reabsorption
across
the
of
amino
cells
of
the
acids.
PCT
About
as
50%
these
of
the
molecules
urea
in
diffuse
the
ltrate
easily
through
Many
membranes.
The
movement
of
solutes
across
the
cell
creates
an
small
and
gradient
into
water
moves
from
the
ltrate
down
a
water
are
to
loops
too
such
the
ltrate
that
blood
transport
as
leaves
the
PCT
,
it
enters
the
loop
of
Henle.
Mammals
iron,
transported
big
to
and
like
are
are
proteins.
they
some
this.
be ltered
substances
After
the
Some
blood.
ions,
Into the
in
potential
attached
the
substances
osmotic
transported
gradient
foc us
moves
so
carry
vitamins
Proteins
are
the
are
not ltered
have
either.
short
loops
loops
that
and
As
short
the
limb
that
loops
ltrate
of
the
The
uid
is
less
role
in
of
it
extend
the
ltrate
loops
medulla.
and
is
the
far
that
to
all
into
to
from
which
a
the
and
water
of
up
end
of
the
the
tissue
the
of
long
medulla.
ascending
loop
loop
to
from
in
uid
the
long
less
solution
from
and
mixture
the
then
enters
concentrated
tip
a
and
concentrated
reabsorb
medulla
have
the
limb
concentrated
that
the
Humans
extending
passes
highly
to
at
descending
provide
used
if
medulla.
more
than
This
is
very
the
10–20%
rst
concentrated
ducts
of
down
gets
The
tip
about
moves
the
the
collecting
not
to
with
loop
concentrated.
DCT
do
extend
the
the
the
PCT
.
tissue
surrounds
the
Summary q uestions
urine.
1
The
highly
concentrated
tissue
uid
is
mainly
the
responsibility
of
Make
the
upper
part
of
the
ascending
limb,
which
has
cuboidal
epithelial
a
large,
labelled
cells
many
pumps
tissue
mitochondria
reabsorb
uid;
sodium
this
part
is
to
provide
ions
from
A
TP
the
impermeable
for
protein
ltrate
to
and
pumps.
pump
nephron
and
the
dilute
uid
enters
the
them
into
the
2
water
.
descending
Make
a
table
components
limb
of
the
loop
it
are
a
region
permeable
potential
to
with
more
water
,
gradient.
The
concentrated
which
walls
diffuses
are
tissue
out
of
uid.
the
impermeable
to
The
ltrate
ions
epithelial
down
and
a
urea.
bend
lower
at
part
the
of
base
the
of
the
loop,
ascending
the
limb
is
uid
is
at
permeable
its
to
most
to
water
3
Explain
and
urea.
the
high
chloride
tissue
Sodium
solute
ions
passively
uid.
ions
Sodium
diffuse
concentration
are
either
through
in
pumped
channel
ions
the
as
are
into
the
medulla.
well
proteins.
recycled
ltrate
as
like
Along
sodium
this
the
ions
ions,
from
to
that
the ltrate
do
and
not.
how
the following
are
their functions:
PCT
cells;
cells
at
the
but
of
the
ascending
limb
of
the
the
of
Henle;
DCT
cells.
maintain
nephron,
or
of
the
blood
concentrated.
sodium
loop
surrounding
show
the
the
top
not
with
section.
walls
water
At
that
glomerulus;
The
to
of
part
adapted for
hairpin
annotate
each
passes
those
through
of
These
become
As
of
lled
the functions
with
diagram
the
diffuse
4
Make
a
table
permeability
of
the
water,
to
of
nephron
sodium
compare
different
(PCT
ions
the
parts
to CD)
and
to
urea.
115
5.4
Osmoregulation
The
Learning outcomes
kidneys
volume
On
completion
should
be
able
of
this
section,
would
you
to
to:

dene
the
explain
term
the
role
coordinating
contain
of ADH
the
duct
and
but
much
dangerously
water
controls
in
activity
of
water
when
to
of
osmoregulation.
this
is
reabsorbed;
dehydrated
dissolve
the
in
the
volume
of
with
solutes
water
that
lost
in
The
if
fatal
we
the
kidneys
not,
then
lter
the
consequences.
need
to
urine
remove.
by
a
large
tissues
Urine
has
The
water
in
in
the
the
body
is
dehydrating
compared
to
when
reabsorbing
there
is
more
sufcient
body.
the
ltrate
that
enters
the
distal
convoluted
tubule
from
the
loop
is
very
determining
dilute
volume
effectors
osmoregulation
The
collecting
the
water
,
become
kidney

of
are
concentration
as
most
of
the
ions
have
been
pumped
out.
The
DCT
is
of
responsible
for
determining
how
much
of
the
remaining
ions
are
urine
excreted.

explain
the
feedback
role
in
of
duct
negative
(CD)
straight
osmoregulation
The
uid
has
the
through
concentration.

describe
and
explain
changes
potential
of ltrate
in
the
discuss
the
presence
in
signicance
uid
glucose
and
protein
through
urine
change
the
in
and
the
it
collecting
may
pass
composition
collecting
ducts,
or
to
maintain
the
high
concentration
of
some
solutes
urea
in
is
the
in
the
to
medulla.
water
The
cells
depending
on
lining
how
the
CD
much
we
can
need
change
to
their
retain.
‘Osmostat’
hypothalamus
that
narrow
blood
monitor
limits.
plasma
osmosis
plasma
causes
them
to
ADH
the
water
water
too
too
and
send
the
and
blood.
and
websites
or
duct
and
to
the
ADH.
target
If
posterior
When
cells
you
of
by
less
the
blood
osmosis.
water
the
cells
function
point,
by
the
point,
out
This
potential
pituitary
stimulated,
are
the
gland
these
epithelial
where
cells
cells
of
the
textbooks
of
collecting
duct
0
H
2
alternative
vasopressin. This
luminal
membrane
will nd ADH
H
its
set
cells
efciently.
set
nerve
within
DCT
.
lumen
the USA,
by
and
kept
foc us
collecting
called
the
passes
the
into
special
is
burst.
of
The
This
below
water
above
passes
less
contains
dehydrated
increases
impulses
vesicles
it
blood.
decreases
water
may
as
the
become
function
cells
contain
into
potential
of
concentrated
potential
the
‘
osmostat’
potential
which
dilute
swell
cells
body ’s
water
tissues,
much
terminals
release
read
the
‘
osmostat’
nerve
S tudy
too
the
the
becomes
increases
The
If
If
is
the
becomes
from
efciently.
you
dilute
little
into
urine.
cells
from
as
trickles
of
The
If
ows
with
and
nephron
clinical
of
DCT
composition
bladder
urine
helping
permeability

the
the
and
tissue
urine
same
to
As
leaves
in
reabsorbed
water
that
0
2
name
suggests
that
it
tight
junction
tight
increases
the
blood
pressure.
It
vesicle
doesn’t,
at
least
not
at
the
aquaporin
concentrations
in
the
junction
with
2
H
0
2
normally found
body.
aquaporin
3
lateral
membrane
Cyclic
H
0
2
AMP
ADH
receptor
ATP
blood
Figure 5.4.1
A cell of the collecting duct responding to
ADH. Aquaporin 1 is in the cell surface membranes of cells
in the PCT and descending limbs of the loops of Henle.
116
H
ADH
plasma
0
2
Module
ADH
the
interacts
with
movement
towards
with
the
ow
and
urine
water
on
the
of
membrane.
into
of
the
the
potential
cell
containing
membranes
sur face
the
membranes
low
receptors
vesicles
luminal
cell
from
lateral
the
the
of
the
membrane,
epithelial
makes
Other
epithelial
in
the
This
cells.
sur face
aquaporins.
cells
much
aquaporins
cells.
medulla
it
These
The
are
where
easier
are
solutes
sodium
leading
vesicles
in
that
ions,
for
fuse
water
basal
contribute
chloride
to
and
to
ions
that
have
the
is
reabsorbed
same
shape
solute
concentration
When
restored
half-life
cells
Australian
genus
hopping
to
(10–30
remove
decreases
to
mediated
by
the
the
set
to
Notomys are
remove
the
of
so
ADH
its
blood
of
vessels
Henle
secretion
concentration
from
these
excess
second
the
loops
to
in
the
the
producing
urine. They
can
of
×25
of
the
world
concentrate
compared
of
record
concentrated
their
it
with
blood
by
a
the
plasma.
medulla.
maintain
the
high
medulla.
aquaporins
water
the
point,
minutes)
the
permeability
in
enters
as
mice
holders for
concentration
water
They
maintenance
Did you know?
factor
urea.
The
Biosystems
move
they
the
to
2
the
cells
water
.
luminal
decreases.
The
messenger
,
effect
cyclic
stops.
in
the
surface
The
of
and
urine
ADH
AMP
ADH
blood
(see
has
a
short
decreases.
The
the
concentration
on
its
page
target
cells
is
103).
Counter-current ow
Y
ou
will
parallel
have
with
concentrated
limbs
of
the
between
sodium
vasa
that
another
.
tissue
loops
them
and
diffusion
the
noticed
one
uid
are
from
in
all
through
chloride
the
ions
which
blood
ows
down
blood
ows
up
to
into
the
recta
medulla.
together
tissue
in
lose
vasa
and
arrangement
the
close
ascending
recta,
loops,
This
the
uid.
lower
and
medulla.
The
the
sodium
are
ascending
substances
concentrates
same
and
all
a
and
medulla
The
reverse
ducts
produce
exchange
nephron
of
limb.
gain
to
descending
they
The
part
descending
water
The
and
collecting
helps
because
principle
chloride
exchanges
the
there
ions
occur
is
applies
as
as
to
the
the
Figure 5.4.2
These test strips are used to
test urine for albumen, ketones and
glucose in urine
through
the
use
thick
section
away
and
This
point
is
kept
of
of
the
method
blood
the
medulla.
energy
the
to
control
within
triggers
events
is
the
limbs.
effect
of
negative
narrow
that
counter
drive
ascending
concentrating
of
This
limits
return
current
pumping
Without
the
the
of
any
water
sodium
this
medulla
feedback
and
multiplier
as
the
the
ions
solutes
would
slight
be
water
of
works
from
potential
the
the
would
diffuse
lost.
deviation
potential
only
from
blood
of
the
to
the
set
the
set
Summary q uestions
point.
1
Dene
2
Explain
the
term
osmoregulation.
Urine tests
T
est
strips
like
those
shown
in
Figure
5.4.2
are
used
to
test
urine
the
following

glucose
to

–
its
conrm
ketones,
for
the
presence
the
diagnosis
which
body
to
using
fat
of
diabetes,
to
may
are
indicate
(see
present
in
metabolise;
instead.
Their
page
the
they
diabetes,
but
requires
more
urine
presence
in
gland, ADH
if
there
produced
indicates
is
not
when
poorly
enough
the
body
glucose
3
switches
managed
Explain
involved
in
which
is
a
plasma
protein
and
should
not
be
blood.
A
positive
result
suggests
high
blood
ltered
pressure,
a
Imagine
or
problems
with
kidney.
is
osmoregulation.
you
are
given
someone
a
yellow
with
from
diabetes
and
told
it
kidney
is
infection
pituitary
negative feedback
undiagnosed
the
posterior
and
how
liquid from
albumen,
the
control
4

of
osmoregulation:
hypothalamus,
tests
134),
are
roles
for:
urine.
Explain
how
you
would
ltration.
use
it
5
a
chemical
contains
Explain
a
why
indicators
of
test
to
reducing
urine
show
that
sugar.
tests
are
useful
health.
117
5.5
Practice
The
Answers to
1
all
Excretion
a
kidney,
exam-style questions
is
a feature
the
of
term
exam-style
all
living
can
questions:
excretion
be found on the
organisms.
Dene
ii
Explain why carbon dioxide must be excreted
excretion.
osmoregulation
accompanying CD.
3
i
and
Figure
5.5.3
shows
a
kidney
nephron
and
associated
blood vessels.
[3]
L
A
from the body and outline how this happens. [5]
B
Many
have
b
humans,
a
along
high-protein
Explain
are
why
with
large
produced
many
other
mammals,
diet.
by
[3]
quantities
of
nitrogenous
C
waste
mammals.
D
K
c
Outline
how
this
nitrogenous
waste
is
processed
J
and
excreted.
[5]
H
2
The
kidneys
main
of
are
excretory
the
body.
E
the
C
organs
Figure
G
5.5.
1
F
B
shows
a vertical
section
Figure 5.5.3
of
a
a
kidney.
i
Identify
the
parts
the
of
kidney
A
ii
to
a
the
following
labelled
D.
Match
letters
given
in
Figure
5.5.3
to
the
statements.
i
site
ii
region
of
ultraltration
[1]
iii
blood vessel with the highest concentration
[4]
Describe
briey
D
of
lowest
water
potential
[1]
A
the functions
of
urea
[1]
Figure 5.5.1
of
the
parts
iv
labelled
C
and
D.
b
Selective
reabsorption
site
of
action
occurs
in
the
tubule
of
Explain
the functional
each
nephron
in
the
5.5.2
shows
a
hormone ADH.
[1]
cell
from
this
part
of
of
advantage
structures
E,
of
H, G
the
and
parallel
J
in
the
kidney.
medulla
Figure
the
proximal
arrangement
convoluted
of
[2]
of
the
kidney.
[3]
a
Diabetes
insipidus
is
a
rare
condition
in
which
large
nephron.
quantities
this
of
dilute
condition
peptide
was
urine
are
treated
hormone. The
produced. A
with
person
injections
mean volume
of
of
with
a
urine
3
produced
After
per
daily
day
before
injections
treatment
given
over
10
was
days,
5.75 dm
the
.
mean
3
volume
c
of
urine
Suggest
explain
taken
d
an
Explain
4
The
a
kidney
Outline
it
had
to
the
be
peptide
injected,
hormone
rather
[2]
effect
of
the
the volume
is
of
peptide
roles
of
hormone
in
urine.
responsible for
the
and
than
mouth.
the
reducing
3.45 dm
identity for
why
by
was
[3]
the formation
ultraltration
of
urine.
(pressure
Figure 5.5.2
ltration)
formation
b
Explain
how
this
cell
is
adapted for
Explain
what
composition
through
118
the
[5]
happens
of
the
to
the volume
convoluted
b
as
tubule.
Explain
of
and
glomerular ltrate
proximal
of
selective
reabsorption
in
the
urine.
[4]
selective
reabsorption.
c
and
it ows
[5]
c
urine
Discuss
how
is
the nal volume
determined
the
roles
homeostasis.
of
by
the
the
and
concentration
kidney.
hypothalamus
[3]
in
[6]
Module
5
The
table
shows
the
glomerular ltrate
composition
and
of
blood
plasma,
b
Describe
urine.
to
c
the
increase
Use
this
2
Biosystems
response
the
water
example
to
carried
out
potential
explain
maintenance
by
of
how
the
the
effectors
blood.
[3]
negative
–3
Component
Concentration/g 100 cm
Increase
feedback
is
used
to
maintain
homeostatic
equilibrium.
Blood
Glomerular
plasma
ltrate
7
The
common vampire
found
protein
7–9
[5]
Urine
0
0
in Trinidad
glucose
0.
1
0.
1
0
urea
0.03
0.03
2.0
–
the
60%
blood
of
its
of
and Central America. This
sleeping
body
mass
protein-rich food
bat’s
0.0001
0.0001
ions
0.32
0.32
blood
0.30–0.35
blood
90–93
97–99
Explain
is
mammals,
bat feeds
blood
the
stomachs
same
is very
ingesting
with
each
water
potential
‘watery’
of vampire
about
meal. This
with
bats
a
as
the
high
concentrate
quickly.
×1
96
collected
–
urine
a
in
but
meals very
Urine from
water
has
plasma
volume. The
0.0400
the
sodium
Desmodus rotundus,
–
on
ammonia
bat,
a
captive
during
and
the
an
urine
common vampire
investigation. The
concentration
bat
rate
were
was
of ow
of
determined
1
why:
over
a
period
of
8
hours. The
bat
took
a
blood
meal
2
glucose
but
not
[2]
2
hours
results
in
[2]
in
the
in
is
plasma
of
[2]
urea
in
the
urine
is
the ltrate
are
present
the factors
by
[1]
in
the
which
urine.
the
[2]
concentrations
compared
c
Urine
is
waste
with
the
routinely
are
blood
increased
in
the
urine
plasma.
tested for
etar
nitrogenous
[2]
glucose
and
are
the
shown
what
steps
might
be
taken
by
a
in
of
the
Figure
investigation. The
5.5.5.
4
of flow
concentration
0.25
3
0.20
0.
15
2
0.
10
1
0.05
0.00
protein.
0
0
Suggest
start
rate
marg
fo
of
after
0.30
the
ydob
ions
the ltrate
ssam
than
in
rep
Calculate
the ltrate,
concentration
concentration
sodium
the ltrate
mc/wofl eniru
b
in
in
3
the
as
present
present
ruoh
urea
protein
rep
urine
the
higher
v
is
the
same
iv
no
yrartibra/eniru
ii
iii
is
fo noitartnecnoc
there
stinu
i
1
2
3
4
5
6
7
8
9
doctor
time/hours
who
identies
glucose
and
protein
in
the
urine
of
Figure 5.5.5
a
patient.
[4]
a
6
The
water
potential of the
blood
is
maintained
Describe
the
narrow
limits. The ow
the
water
chart
potential
of
in
the
Figure
blood
5.5.4
is
it
of
effect
urine
and
of feeding
its ow
on
rate. You
shows
use gures from
the
graph
to
illustrate
controlled
your
when
immediate
concentration
should
how
the
within
answer.
[4]
decreases.
b
X
Explain
the
effect
of feeding
on
the
rate
of
urine
Y
production.
c
Explain
of
effectors
why
[3]
D. rotundus
excretes
large
quantities
urea.
[3]
decrease
d
Vampire
bats
are
concentrated
water
the
produce
that
a
much
produced
more
by
humans. Suggest
how
they
are
able
to
do
this.
[2]
blood
Did you know?
Figure 5.5.4
a
to
than
increase
potential
response
of
able
urine
Name:
Search
i
the
part
ii
the
hormone
of
the
iii
the
effectors.
brain
shown
shown
by
Y
by
box
X
[1]
[1]
of
online for
‘common
D. rotundus feeding
two
other
parasitic
species
of
on
vampire
livestock,
vampire
bat’. You
such
bat. These
as
can nd lm
pigs. There
three
are
the
are
only
mammals.
[1]
119
2
Biosystems
6.
1
Structure
maintenance
of
Learning outcomes
neurones
Structure of the
The
On
completion
should
be
able
of
this
section,
nervous
describe
to:
and
the

motor
structure
of
central
describe

neurones
the functions
divided
into
two
parts:
nervous
system
(CNS),
which
is
divided
into
the
brain
and
cord
sensory
peripheral
nerves

is
system
you
spinal

system
nervous
nervous
attached
to
system
the
(PNS),
brain
and
which
spinal
consists
nerves
of
nerves
attached
to
–
cranial
the
spinal
of
cord.
neurones
nerve

in
the
transmission
of
impulses
describe
the
structure
of
There
are
two
which
are
also
state
the
effect
of
myelination
distances.
speed
of
outline
the
surface
within
neurones,
the
nervous
transmit
system.
Nerve
information
very
cells,
fast
These
cells
are
supported,
protected,
and
in
some
over
cases
by
glial
cells
impulses
There

types
as
on
insulated,
the
cell
known
myelin
long

main
structure
membranes
of
of
are
three
types
of
neurone:
cell
neurones.

sensory

relay
neurone
neurone
(also
known
as
connector
neurone
or
intermediate
neurone)
Link

We
used
unit
in
the
the
kidney.
idea
of
pancreas
(See
page
No
the functional
and
in
motor
neurone
simplest
the
consists
112.)
which
SENSORY
nucleus
NEURONE
cell
body
neurone
can
bring
functional
of
one
controls
myelin
node
sheath
Ranvier
of
about
unit
each
the
in
of
knee
a
piece
the
the
jerk
of
behaviour
nervous
neurones.
reex,
system
In
there
some
is
no
Sensory
of
on
is
a
its
own.
reex
reex
arcs,
connector
The
arc,
which
such
as
that
neurone.
neurones:
axon

transmit
impulses
from
sensory
terminals
cells
on
(receptor
or
sensory
relay
nerve
or
cells)
endings
to
the
CNS
motor

have
their
cell
bodies
in
neurones
axon
dendron
swellings
on
nerves
just
outside
sensory
the
CNS
dendrites

Figure 6.1.1
A sensory neurone
terminate
neurones
Motor
MOTOR
NEURONE
dendrites
myelin
node
of
sheath
Ranvier
axon
on
connector
within
the
CNS.
neurones:
axon
terminals

on
transmit
to
impulses
effectors,
such
from
as
the
CNS
muscles
and
effectors,
glands
such
as

have
their
cell
bodies
within
the
muscles
CNS.
or
nucleus
cell
glands
body
Relay
Figure 6.1.2

S tudy
neurones:
A motor neurone
transmit
impulses
to
neurones
motor
from
sensory
foc us

are
found
entirely
within
the
CNS.
Take
care
structure
neurone
over
using
with
many
is
a
nerve
the
terms
nerve
cell.
nerve
cells
and
neurone. A
surrounded
by
nerve
is
a
multicellular
protective fibrous
tissue. A
Myelinated
impulses
without
120
neurones
much
faster
myelin.
transmit
than
neurones
Module
Component
Structural features
cell
nucleus
body
(with
2
Function
nucleolus);
RER
and
transcription
and
translation
to
produce
membrane
proteins
mitochondria
cell
surface
phospholipid
+
membrane
impermeable
bilayer;
+
to
ions;
+
/K
Na
pump
channel
proteins;
pump
proteins
dendron
long,
thin
dendrites
similar,
axon
long,
process(es) from
terminal
swollen
endings
mitochondria
but
thin
allow
smaller
than
process from
end
molecules
of
of
axon
and
cell
body
cell
body
release
large
of
in;
ions
towards
surface for
impulses
through
across
cell
away from
synaptic
the
membrane
body
in
synapses from
neurotransmitter
impulse
neurotransmitter
K
impulses
transmits
with
and
movement
provide
containing
vesicles
out
transmits
dendrons
+
Na
cell
sensory
many
other
neurones
body
molecules from
cleft;
neurones
reform
vesicles
to
carry
neurotransmitter
molecules
Myelin
The
and
neurones
sensory
Schwann
columns
cell .
of
Schwann
some
rich
in
of
that
are
with
layer
axon
or
allows
the
tiny
of
nodes
of
the
the
from
very
the
of
phospholipid.
uid
to
in
as
‘gutters’
is
Myelin
ions
cell
cells
the
formed
exposed
and
upon
The
by
to
of
the
cell
membrane
through
about
there
neurone.
is
the
diffuse
covers
meet
motor
dendrons)
layer
insulates
cannot
All
the
myelinating
(axons
layer
between.
of
called
develops,
is
Schwann
surface
cell
neurone
processes
there
Schwann
the
myelinated.
glial
system
uid
Each
two
reach
the
proteins.
tissue
are
of
within
of
cytosol
few
Where
lie
nervous
until
6.1.2
type
neuronal
quantities
with
a
length
continues
dendron.
tissue
As
and
by
neurones
whole
around
This
membrane
thick
the
grow
6.1.1
supported
The
uid.
phospholipid
neurone
this
tissue
cells
Figures
are
cells.
neurones.
membrane
in
Unmyelinated
these
surrounding
of
shown
neurones
is
1–3 mm
a
These
gap
gaps
Ranvier
Structure of the
cell
surface
Figure 6.1.3
membrane
A cross-section
of the axon
of a myelinated neurone. You can see the
Conduction
dendrons
their
ow
forward
of
and
is
high
ow
neurone.
nerve
An
impulses
axons.
of
These
and
ions,
action
relies
ions
impulses
action
do
on
the
not
decay
is
the
very
quickly.
potentials
potential
movement
travel
net
occur
effect
In
at
of
far
of
as
order
to
intervals
ion
ow
ions
the
along
layers of cell membrane that make up the
resistance
‘boost’
along
to
myelin sheath.
the
the
across
the
Summary q uestions
neurone
neurone.
membranes.
In
In
myelinated
unmyelinated
neurones
neurones
action
they
potentials
occur
occur
all
only
along
at
the
the
1
nodes
of
Make
a
motor
Cell
surface
cells,
except
types,

large
but
membranes
they
four
have
voltage-gated
voltage-gated

potassium
of
axons
large
concern

and
numbers
dendrons
of
ion
are
just
channels.
the
same
There
are
as
and
several
us:
sodium
of
ion
potassium
channel
ion
proteins
channel
neurone,
neurone.
other
2
Label
annotate
each
Explain
part
the
proteins
leak
channel
leak
channel
addition,
membranes.
there
are
with
a
a
b
a
sensory
diagrams
the functions
have
labelled.
differences
pairs:
nervous
and
between
central
and
spinal
systems,
nerves,
proteins.
myelinated
In
of
proteins
cranial
sodium
and
both
you
the following
peripheral

diagram
Ranvier
.
sodium
potassium
pump
proteins
in
these
and
unmyelinated
neurones,
sensory
neurones,
axon
and
and
motor
dendron.
121
6.2
The
nerve
Learning outcomes
On
completion
should
be
able
of
this
impulse
Resting
section,
The
neurone
that
if
outline
is

how
the
how
resting
and
potential
maintained
nerve
cells
voltmeter
,
negatively
resting
to
transmit
explain
has
placed
a
potential
either
side
difference
of
the
across
membrane
it.
This
and
means
connected
a
difference
charged
potential
with
is
is
recorded
respect
usually
to
of
the
the
written
order
outside
as
of
of
70 mV
.
the
The
neurone
inside
to
so
is
the
–70 mV
.
resting
potential
is
the
result
of
an
unequal
distribution
of
ions
impulses
across

are
are
The
stimulated
electrodes
to:
established
explain
membrane
you
a

potential
how
action
potentials
how
action
potentials
are
membranes.
resting
potential.
All
The
membranes,
factors
that
even
plant
contribute
cell
to
a
membranes,
resting
have
potential
a
are:
formed


explain
contribute
to
the
transmission
the
presence
charged
of

sodium
impulses.
two

the
foc us

resting
a
potential
may find
it
varies
given
–60 mV
to
the
leakage
all
cells
potential
membrane
cells
have
even
similar
to
in
have
those
across
is
the
cell
a feature
that
common. Some
action
plant
potentials
described
here for
of
As
of
the
core
as
negatively
pump
out
three
sodium
ions
for
every
in
membrane
which
does
proteins
through
some
the
ions
proteins
for
A
the
to
not
are
ions.
The
permit
shut
so
phospholipid
the
movement
sodium
and
bilayer
of
ions
potassium
ions
them
potassium
inside
so
of
few
,
are
sodium
cell
neurone
at
resting
concentration
higher
the
in
very
ions
concentration
is
nothing
cell
in
when
ions
cell
fact,
through
is
the
negatively
diffuse
selective.
so
is
through
attracted
of
there
out
There
is
channel
by
the
the
very
potassium
charged
through
are
very
little
a
resting
negative
sodium
sodium
ions
ions
this
leak
channel
attracts
these
few
channels.
leak
diffusion
of
channel
sodium
ions
ions
in
the
attraction
inside
proteins
negative
charge
and
the
down
interior
,
a
the
cell.
With
sodium
so
inside
cell
can
the
–
an
a
with
–
there
is
a
higher
happens
be
put
only
all
use
cells,
in
interior
do
gradient
in
to
negative
not
concentration
cell
ions
and
This
ions
making
the
potassium
gradients
neurone.
for
potential.
outside
concentration
ow
added
at
has
for
The
current
an
of
is
potassium
unusual.
the
there
it
potential
gradients
concentration
forwards
neurones.
S tudy
such
foc us
into
resting
cell,
–75 mV.
proteins
surface
the
the
Channel
A
inside
between
in
potassium
S tudy
anions
that
pumped
channel
diffuse
proteins.
range
organic
pumps
ions
hydrophobic
voltage-gated

cells. You
potassium
potassium
cannot
The
many
impermeability
has
S tudy
of
proteins
they
but
electrochemical
so
driving
of
the
diffuse
they
are
gradient.
foc us
Action potentials occur along the
whole length of myelinated neurones,
but only at nodes of myelinated
Impulses
travel
gradients
the
sodium
which
ions
along
cell
out
and
constantly
neurones
continually
potassium
recharges
all
uses
the
ions
itself
time.
energy
in.
using
in
T
o
maintain
the
The
form
cell
energy
is
of
the
A
TP
therefore
from
concentration
to
pump
like
a
battery,
respiration.
neurones. See Question 6 on page 127
.
The
resting
potential
potential
difference
hyperpolarised
To fire or
Motor
If
the
reach
no
the
of
stimulus
122
effect
is
threshold,
frequency
.
the
receive
neurones.
the
change.
less
Membranes
negative
potential
or
are
depolarised
more
difference
positive;
becomes
more
when
they
the
become
negative.
not to fire?
overall
impulse
base
when
neurones
connector
can
becomes
is
sent.
axon,
The
the
impulses
Some
to
of
then
an
is
threshold
is
are
the
impulse
the
determines
the
these
depolarise
This
higher
from
many
sensory
excitatory
neurone
is
sent
between
frequency
–50 mV
(see
the
rule.
impulses
some
membrane
along
all- or-nothing
whether
and
neurones
are
and
Question
The
sent
on
axon
and
inhibitory
.
If
to
not,
hillock
at
then
the
their
the
page
many
sufficiently
neurone.
–40 mV
;
8
are
and
greater
127).
the
Module
Action
If
the
potential
axon
hillock
S tudy
initiates
a
nerve
impulse,
then
an
action
The
membrane
is
depolarised
and
current
ows
foc us
potential
The
occurs.
2
forward
along
movement
voltage-gated
neurone.
which
to
triggers
open.
and
triggers
feedback
more
current
some
Sodium
gradient
This
This
in
yet
The
feedback
more
This
to
potential
sustainable
and
to
their
open.
one
the
of
ends
is
for
sodium
ions
facilitated
is
leads
‘spike’
to
the
a
to
of
for
the
shown
+40 mV
.
sodium
The
and
in
No
Figure
positive
action
foc us
of
what
is
responsible
impulse
online for
nerve
impulses
happens
occurs
at
along
when
one
a
some
an
place
that
action
along
a
neurone.
potential
+
+
–
–
+
–
–
+
+
–
–
–
–
+
+
–
–
+
+
+
–
–
+
+
S tudy
Refractory
The
of
an
Search
animations
show
channels
potential
propagating
neurone.
potential
direction
is
positive
more
close.
action
proteins
diffusion.
S tudy
There
+30
when
through
electrochemical
amplitude
the
ions
channel
membrane,
more.
depolarisation
stroke
of
proteins
down
some
difference
this
region
channel
increase
upward
next
axon
proteins
slight
opening
the
the
depolarises
initial
is
maximum
is
into
channel
the
the
voltage-gated
diffuse
proteins
depolarisation.
6.2.1.
the
depolarises
membrane
which
channel
of
ions
the
ow
of
the
foc us
means
existence
of
‘unresponsive’.
refractory
periods
impulse
means
that
each
action
potential
is
a
40
Vm/ecnereffid laitnetop
discrete
event. Action
potentials
do
repolarising
polarised
not fuse
(resting
(resting
potential)
potential)
together
continuous
0
to
give
a
depolarisation.
Summary q uestions
1
State
the
resting
values
enarbmem
potential
action
of
potential;
difference
potential;
change
the following:
maximum
in
during
an
maximum
potential
difference
depolarised
hyperpolarisation
noxa
during
(action
an
action
potential.
potential)
2
The
action
potential
is
described
65
as
0
1
2
3
4
an
all-or-nothing
Explain
what
Explain
how
this
response.
means.
Figure 6.2.1
time/ms
The
increase
that
there
neurone.
in
are
sodium
more
This
ions
positive
current
An action potential
reverses
ions
the
that
depolarises
charge
can
the
ow
next
inside
as
the
patch
of
the
neurone
current
strength
so
inside
membrane,
3
the
4
Describe
be
the
next
node
in
a
myelinated
neurone.
Meanwhile,
the
to
the
across
potential
so
potential
is
the
that
not
membrane
another
achieved
action
by
needs
to
potential
pumping
out
be
restored
can
occur
.
sodium
to
the
Instead
the
voltage-gated
channel
proteins
for
That
the
ions
ow
out
down
their
takes
potassium
electrochemical
and
potassium
channels
passage
an
gradient.
ions
potential.
channels
shut’
open
The
(albeit
While
are
briey;
again
period
when
when
restore
is
the
is
they
when
the
resting
the
sodium)
thrown
another
potassium
It
is
back,
open
are
as
if
the
the
open,
these
The
of
The
ions
do
not
the
loss
diffuse
out
in
potential.
Draw
a
diagram
and
of
an
action
annotate
it
with
of
potential
sodium
are
‘bolted
proteins
of
the
changes
in
will
6
difference.
The conduction of impulses in
neurones is influenced significantly
by temperature. Suggest why
respond
overshoot
action
resting
gates
channel
the
and
depolarisation.
channels
period .
restores
proteins
open.
sodium
refractory
more
not
are
by
not
channel
do
‘bolts’
stimulated
because
and
potassium
and
the
time
depolarisation
potential
the
closed
of
potassium
during
too
explanations
positive
sodium
voltage-gated
resting
potential
potassium
that
potential
5
long.
changes
resting
Restoring
ions.
the
stimulus.
voltage-gated
channels
difference
a
encode
which
occur
will
of
neurones
restoring
than
neurones conduct impulses at
to
resting
necessary
to
faster speeds at temperatures near
40 °C than at 10 °C.
potential.
123
6.3
Synapses
Neurones
Learning outcomes
are
continuous
On
completion
should

be
able
describe
of
this
section,
that
you
have
separate
very
along
structure
of
cells.
gap
describe
that
synapse
the
occurs
The
synaptic
sequence
during
the
of
events
synapses
is
target
it
synapse,
of
cells
of
are
to
section,
and
tiny
one
another
anemones
impulses
gaps
to
and
travel
between
form
jellyfish
in
the
both
nerve
the
term
side
rather
of
in
than
the
and
tends
gap.
width.
the
to
be
region
applied
The
gap
of
the
to
the
itself
T
ransmission
post-
is
called
across
the
these
electrical.
are
such
either
as
other
muscles
neurones
and
or
,
glands.
in
the
case
Synapses
of
between
are
as
interneuronal
synapses
and
those
at
muscles
as
junctions.
categorised
about
roles
of
synapses
is
according
impulses flow
in
between
look
to
the
neurotransmitter
Synapses
of
the
this
synapses
that
use
in
which
released.
acetylcholine
nor-adrenaline
are
is
Y
ou
the
Within
the
central
nervous
system
there
are
adrenergic
many
different
one
neurones.
out for
importance
cholinergic
to
neurotransmitters;
direction
into
sea
which
are
neurone
20 nm
neurones
known
know
synapses.
that
in
there
although
other
effectors
neurotransmitter
.
show
in
foc us
need
the
fuse
synapses.
Synapses
of
the
about
chemical
neuromuscular
One
systems
cells,
pre-synaptic
on
is
neurones,
neurones
S tudy
a
the
neurone
cleft ;
The
roles
is
of
synaptic
motor
outline
nerve
not
Even
synaptic
transmission

nervous
their
do
a
terminations

simple
directions
They
structures.
to:
the
cholinergic
cells.
multicellular
In
this
acid
(GABA)
that
one
acts
of
at
the
most
inhibitory
common
is
gamma
amino
butyric
synapses.
explanation
role.
Cholinergic
A
nerve
here
terminal
contains
cytoplasm
When
an
events
1
An
2
In
impulse
are
impulse
to
arrives
calcium
with
at
a
called
a
channel
bouton.
proteins
The
and
membrane
the
acetylcholine.
a
sequence
of
events
occurs.
These
diagram.
synaptic
ions
The
this
is
diffuse
into
the
concentration
a
steep
the
bulb.
voltage-gated
channel
proteins
for
cytoplasm
of
calcium
down
ions
their
inside
electrochemical
cytoplasm
is
very
gradient.
Calcium
ions
trigger
the
movement
of
vesicles
containing
along
neurone
ion
synapse
the
the
often
open.
gradient.
vesicle
in
at
4
synaptic
swelling
depolarisation,
1
presynaptic
a
vesicles
arrives
Calcium
so
in
summarised
response
low,
ends
voltage-gated
contains
calcium
3
synapses
microtubules
towards
the
pre-synaptic
acetylcholine
+
_
_
+
membrane.
2
2+
2+
Ca
+
Ca
+
5
2+
2+
The
vesicles
fuse
with
the
pre-synaptic
membrane
Ca
Ca
2+
open
2+
calcium
Ca
Ca
and
channel
release
molecules.
their
This
contents
is
of
acetylcholine
exocytosis.
3
+
+
presynaptic
6
Acetylcholine
molecules
diffuse
across
the
synaptic
4
gap
membrane
synaptic
+
Na
7
acetylcholinesterase
postsynaptic
membrane
8
open
ion
dendrite
+
channel
postsynaptic
neurone
Synaptic transmission. Follow the sequence of events
described as 1 to 11.
124
post-synaptic
channel
membrane.
The
channel
proteins
open
to
allow
diffusion
9
sodium
Figure 6.3.1
the
chemical-gated
10
7
+
on
with
+
Na
6
15nm
combines
proteins
5
+
Na
cleft
and
ions
synaptic
into
the
neurone.
cytoplasm
of
the
post-
of
Module
8
The
9
Acetylcholine
post-synaptic
membrane
is
2
Biosystems
depolarised.
S tudy
down
by
groups
the
and
With
enzyme
choline,
membrane
10
molecules
(or
removal
into
of
leave
the
protein
channels
acetylcholinesterase .
which
the
diffuse
back
surrounding
acetylcholine,
the
The
into
glial
and
are
products
the
are
acetyl
Neurotransmitters
pre-synaptic
cells).
post-synaptic
If
the
sum
greater
membrane
is
of
all
its
the
impulses
threshold,
arriving
then
an
at
the
impulse
post-synaptic
is
sent
(see
although
they
between
travel
between
neurone
page
are
molecules,
is
than
foc us
broken
repolarised.
11
maintenance
very
neurones
cell
the
signalling
distance
neurones
and
or
effector
cells
small.
is
122).
Link
Roles of
synapses
Many

T
ransmission
of
impulses.
The
main
role
of
a
synapse
is
to
at
impulses
to
be
transmitted
from
one
neurone
to
another
.
They
so
that
the
pre-synaptic
pre-
and
post-synaptic
proteins).
systems
membrane
post-synaptic
membrane
The
have
neurones
vesicles
has
has
in
and
vesicles
receptors
sea
of
membranes
are
receptors
on
and
both
jellyfish
there
and
Integration
different
release
Synapses
both
neurone.
stimulate
lowers
depolarise
the
the
Summation.
neurone.
The
a
allow
excitatory
neurotransmitters
neurones

impulses.
neurones,
synaptic
This
of
that
and
inhibitory.
stimulate
hyperpolarisation
potential
difference,
This
means
several
neurones
also
achieved
that
firing
at
if
from
released
the
making
one
the
different
neurone
same
time
of
this
these
on
174.
of
impulses
Excitatory
by
in
more
in
neurone.
difficult
nervous
Expect
post-
inhibitory
post-synaptic
it
neurones
the
is
neurones
to
does
may
not
do
converge
stimulate
so.
much
to
learn
about
the
from
to
your
the
Summation
one
hear
of
especially
of
exciting
brain
lifetime. You
yourself
on
system,
the field
number
impulses
about
Did you know?
neurone.
Many
more
channel
nervous
depolarisation
in
is
sides.
integration
neurotransmitters
receptors
one
the
There

is
different.
neurotransmitter
(chemical-gated
anemones
with
Nicotine
are
page
The
interact
synapses.
and
polarised
drugs
allow
of
synapses
the
during
amuse
estimates
neurones,
in
brain.
discoveries
research
can
by finding
the
glial
of
cells
the
and
brain.
next,
may
Did you know?
be
neurone
so
by
that
increasing
the
the
frequency
depolarisation
is
of
impulses
sufficient
to
from
stimulate
one
the
next.
Electrical

Dispersal
of
impulses.
The
axon
may
divide
into
many
branches
gap
stimulate
many
other
neurones,
so
that
information
can
spread
one
source
to
many
effectors
in
the
body
or
from
one
source
areas
within
the
central
nervous
system.
This
is
exist
neurones
important
and
post-synaptic
the
body
to
meet
dangerous
3.5 nm. The
membranes
so
close together that
impulses
in
cross them without the
preparing
in which the
is
to
are
many
between
out
prefrom
synapses
to
use of
situations.
chemical transmission. They

Filtering
out
impulses.
Impulses
with
low
frequency
are
filtered
out
and
the
depolarisation
of
the
post-synaptic
neurone
does
not
reach
sometimes
sensory

the
prevents
the
CNS
being
inundated
with
some
in our
and we
brains.
unimportant
information.
Memory
in
This
bidirectional
the
have
threshold.
are fast
as
is
thought
to
be
a
function
of
the
many
synapses
brain.
Summary q uestions
1
Define
2
Make
the
a
explain
large,
Describe
4
Electrical
5
how
and
chemical
Identify
the
showing
It
may
cholinergic synapse.
labelled
the function
3
of
term
a
an
each
impulse
chemical
synapses
in
structures
junction
help
diagram
of
you
to
is
of
part
a
visible
a
exist.
nervous
between
make
you
transmitted
synapses
the
cholinergic
that
in
the
two
sketch
across
Explain
and
a
synapse.
the
advantage
system.
electron
neurones
of
synapse
label.
the
micrograph
(Figure
structures
6.3.2).
and
label
them.
Figure 6.3.2
Electron micrograph for Summary question 5
125
6.4
Practice
The
Answers to
1
a
all
Explain
nervous
exam-style questions
the
exam-style
difference
can
between
a
questions:
system
be found on the
neurone
and
a
nerve.
accompanying CD.
3
a
Describe how differences in the permeability of the
[2]
cell surface membrane to certain ions contribute
to the resting potential of a neurone.
Figure
6.4.
1
is
a
diagram
of
a
[3]
neurone.
Figure
6.4.2
shows
an
action
potential
in
a
sensory
A
neurone.
D
40
B
Vm/ecnereffid
0
laitnetop
Schwann
cells
region A
region
B
enarbmem
C
noxa
65
Figure 6.4.1
0
b
i
Name
A,
B,
C
and
D.
1
2
3
4
[4]
time/ms
ii
State
the
direction
taken
by
nerve
impulses
in
Figure 6.4.2
the
c
Name
neurone
the
describe
in
the
neurone
its
role
in
diagram.
shown
in
[1]
Figure
communication
6.4.
1
within
Explain
a
[2]
the
role
of
the Schwann
cells.
[2]
c
2
Neurones
are
organised
into
reex
arcs. The
Explain
what
i
from
–65 mV
ii
from
+40 mV
Nerve
impulses
arc
is
a
monosynaptic
reex
arc
that
involves
neurone
and
a
motor
Make
a
table
to
show
the
FOUR
structure
b
i
motor
and function
of
neurones.
how
impulses
this
travel
synapse
in
one
ensures
4
a
[1]
Stimulation
neurone
of
does
the
not
in
(region
either
[3]
B).
[3]
direction
neurone.
towards
the
Explain
central
why
why
stimulation
The
speed
of
a
motor
always
motor
by
a
and
not
in
the
opposite
system
direction.
Explain
how
the
sensory
strengths
neurones
of
stimuli
send
to
skin
is
nerve
about
neurone
result
in
[3]
by
the
Describe
Figure
that
direction.
neurone
sensory
the
structure
of
a
myelinated
6.4.3
sodium
a
ion
[5]
shows
closed
channels from
and
the
open voltage-gated
cell
surface
membrane
neurone.
sensory
may
not
respond
to
[3]
,
touch
but from
receptors
some
in
pain
–1
receptors
it
is
about
1.0 m s

d
Explain
what
causes
impulses from
126
these
[3]
sensory
impulse
neurone.
impulses from
80 m s
[3]
information
the CNS.
–1
the
an
impulses
nervous
transmission.
Explain
in
neurone.
of
c
–65 mV
travel
(region A)
[4]
cholinergic synapse. Explain what this means.
Explain
to
+40 mV
sensory
The synapse between the two neurones is a
ii
membrane
comparisons
about
and
the
neurone.
d
between
to
can
sensory
travel
(CNS)
a
change
a
only
sensory
to
simplest
isolated
reex
happens
potential:
mammal.
d
b
and
the
difference
receptors.
in
speed
Na
of
[2]
Figure 6.4.3

Na
Module
b
Describe
proteins
the
changes
shown
in
that
the
occur
diagram
to
the
during
Explain
Biosystems
Compound
Effect
at
curare
competes
roles
in
i
voltage-gated
ii
sodium
Sensory
synapses
[3]
the
neurones
potassium
potassium
neurones
ion
channels
sites
acetylcholine for
and
blocks
them
[3]
pumps.
terminate
with
of:
eserine
a
cholinergic
action
receptor
5
maintenance
channel
an
potential.
c
2
competes
with
the
site
acetylcholine for
[2]
in
the CNS
active
of
on
acetylcholinesterase
connector
synapse
b
between
Describe
when
neurones.
the
an
Describe
the
two
sequence
impulse
of
arrives
the
structure
of
the
neurones.
events
at
the
end
methylmercury
[4]
that
inhibits
of
the
to
stimulate
the
connector
neurone.
Outline
the
roles
of
synapses
in
the
activates
[4]
b
State
on
Some
information
about
neurones from
is
shown
in
the
and
An
explain
transmission
antidote for
the
effect
across
of
each
cholinergic
compound
curare
poisoning
synapses.
is
to
use
[8]
eserine.
table.
Explain
Animal
chemical-gated
channels
different
c
animals
some
ion
nervous
system.
6
that
acetylcholine
[7]
sodium
c
enzyme
sensory
nicotine
neurone
the
synthesises
occurs
Myelinated or
Diameter/
Rate of
unmyelinated
μm
transmission
8
why.
[3]
An isolated neurone was placed into a trough
containing a physiological solution resembling tissue
of
impulses/
uid. Electrodes were placed at one end of the neurone
–1
m s
to stimulate it. Recording electrodes were placed at
crab
unmyelinated
30
5
squid
unmyelinated
500
25
the other end to record the passage of nerve impulses.
a
Explain
why
resembling
frog
myelinated
12
Stimuli
30
of
neurone
frog
myelinated
14
35
cat
unmyelinated
15
2
the
different
and
neurone
tissue uid,
has
intensities
impulses
to
rather
be
kept
than
were
in
applied
recorded. The
a uid
water.
results
to
[2]
the
are
in
the
table.
Stimulus
Impulse or
Frequency of
applied/mV
not
impulses/number s
–1
cat
a
myelinated
The
table
rate
of
shows
20
that
transmission
i
State
the
ii
Explain
100
two features
of
inuence
impulses.
two features.
how
each
one
Suggest
of
c
7
the
neurone
roles
cats,
as
Explain
how
along
myelinated
a
The following
inuences
action
of
the
shown
two
in
the
rate
potentials
structures
are
none
0
30
none
0
40
none
0
50
yes
10
60
yes
25
70
yes
70
80
yes
100
types
table.
[2]
propagated
[6]
are found
ion
channel
at
calcium
acetylcholinesterase,
channel
10
of
neurone.
mitochondria,
ion
different
the
voltage-gated
sodium
0
[4]
likely
in
none
[1]
transmission.
b
0
the
synapses.
proteins, vesicles,
chemical-gated
proteins
b
a
Describe
in
the
the function
transmission
of
of
an
each
of
these
impulse
structures
across
drugs
interacting
The
table
that
act
in
the
table
information
to
about
explain
the
how
strength
neurones
of
[3]
[10]
and
with
shows
at
data
stimuli.
c
Many
the
encode
a
synapse.
Use
poisons
have
their
effects
by
synapses.
the
properties
cholinergic
is
d
of four
synapses.
compounds
Suggest
able
Make
other
to
a
table
between
ways
transmit
to
in
show
FOUR
coordination
coordination
by
which
the
information
the
by
nervous
about
[2]
comparisons
hormones
nervous
system
stimuli.
and
system.
[4]
127
3
Applications
1.
1
Health
Learning outcomes
of
Defining
Health
On
completion
of
this
section,
be
able
is
to
not
define
of

and
the
social
discuss
the
the
health
Physical
physical,
aspects
explain
of
mental
and
health
Physical
the
term
name
eleven
and

at
categories
describe
least
category
an
have
S tudy
up
as
of
one
example
of
each
disease.
refers
is
not
injury
it
can
health
mean
tend
different
to
physical
health,
mental
health
and
social
health.
health
to
in
and
symptoms
many
the
proper
good
have
that
people
condition
Mental
Some
foc us
many
health
find. Also
out
as
of
functioning
health
some
may
have
broken
of
a
the
body
disease
bones.
If
or
systems.
may
someone
is
have
ill,
they
can
identify
and
report
to
a
they
doctor
.
of
that
this
and
ask
compare
disease
different
understand
your
definitions
own
by
the
with
the
you
people
may
does
feel
not
‘healthy ’,
yet
show
but
any
in
fact
may
be
developing
a
symptoms.
can
and
those
of
no
perfectly
may
be
health
that
healthy
they
when
hypochondriacs,
Depression
physical
may
imagine
and
restrict
a
person’s
but
the
inventing
anxiety
symptoms,
have
examined
are
there
ability
to
by
a
severe
many
function
of
health
symptoms
more
are
symptoms
a
disease,
worker
.
and
pain
conditions
behavioural
normally
in
but
People
when
where
like
none
there
problems
are
that
society.
what
terms. Write
definitions
them
as
of
aspects of
people
exist.
they
satisfactorily
Denitions
the features
appear
terms
dene
people.
each
give
Look
to
of
disease
disease
of
things:
aspects of
who
However
,
disease
three
health
Someone
will

term
groups
meaning
suffered

easy
to:
term
discuss
an
different
emphasise

health
you
things
should
biology
Social
Y
ou
others.
aspects of
may
point
know
that
cannot
we
the
are
sur vive
people
live
in
health
phrase
highly
totally
large,
‘No
social
alone
dense
man
is
an
animals
and
island’,
that
without
populations.
live
others.
Y
et,
no
which
in
makes
family
Most
matter
of
the
groups
the
how
and
world’s
dense
the
Did you know?
population
between
WHO
is
an
It
has
organisations,
American
seven
social
own
interactions
personal
with
space.
others
and
The
our
compromise
solitude
we
seek
constitutes
our
health.
Pan
In
1946,
the
World
Health
Organization
(WHO)
dened
health
as:
Health Organization
‘a
state
of
complete
physical,
mental
and
social
well-being
and
not
has offices throughout
merely
the Caribbean. The
the
absence
of
disease
and
inrmity.’
PAHO website
Society
pages for
benets
from
having
a
healthy
population.
Not
a
society
simply
several Caribbean
free
regional
our
regional
including the
(PAHO), which
hosts web
need
agency of the United
social
Nations.
we
of
disease,
but
one
where
people
are
able
to
participate
actively.
Many
health organisations.
people
view
services
tness
On
the
with
and
as
purchased
a
commodity
in
the
form
–
of
provided
dr ugs,
by
government
health
foods
and
health
access
to
clubs.
other
holistic
about
‘health’
hand,
health
how
the
for
their
yoga,
both
meditation
the
mind
breathing,
stresses
and
diet
strains
of
and
and
and
tai
body;
chi
spirituality
modern
teach
people
us
are
can
to
achieve
taught
help
to
them
think
to
deal
life.
Disease
Figure 1.1.1
Each child is born with a
Disease
is
often
dened
as
a
malfunction
of
the
mind
or
body.
A
disease
genetic potential; children need good
is
usually
a
disorder
of
a
specic
tissue
or
organ
of
body
due
to
a
single
cause.
physical, mental and social health to
realise that potential and to play a full and
active part in society
128
Some
diseases
causes
and
are
affect
many
described
as
parts
the
multifactorial.
and
others
have
several
Module
3
Applications
of
biology
Categories of disease
Different
These
aspects
aspects
of
disease
include
are
causes,
used
to
effects
classify
on
the
diseases
body
,
into
duration,
categories.
tissues
or
organs
S tudy
affected
and
associated
disease,
which
we
risk
have
factors.
limited
in
There
the
are
table
to
many
just
different
eleven.
categories
Almost
all
The
diseases
t
into
more
than
one
category
as
you
can
see
in
the
categories
there
Definition
Examples
know
are
and
plenty
about
permanent or temporary
multiple
damage to any part of the body
dengue fever,
diseases
sclerosis,
measles
changes
may
or
to
may
physical
acute
disease
disease
mind,
not
which
have
that
and
answer
a
depression,
(or
a
rapid
short
often
lasts for
causative
onset
that
influenza,
S tudy
with
a
slow
long
onset
chronic
agent
is
a
pathogen
disease
caused
degenerative
a
cause
the
way
infectious
they
listing
Summary
are
some
and
question
4.
not
foc us
bronchitis
dengue fever,
caused
by
a
related
HIV/
to
measles
stroke,
pathogen
deficiency
of
give
us
other
ways
to
time
AIDS,
any
by
types
dengue fever
time
communicable)
non-infectious
Start
different
anxiety
categorise
infectious
you
but
schizophrenia,
Risk factors
that
that
table,
cause
with
lasts for
chronic
the
the
more.
the
transmitted. Try
then
mental
disease
in
2)
organisms
physical
are
(from Units
thinking
1
of
table.
should
Category
foc us
of
to
diseases
as
some
occupations,
are
income
and
poverty.
multiple
sclerosis
by
a
poor
diet
iron
deficiency
in
coronary
anaemia
Summary q uestions
gradual
decline
body
functions
heart
disease,
HIV/AIDS
1
inherited
(or
a
genetic)
genetic
faulty
disease
allele
recessive
or
caused
(either
by
a
sickle
dominant,
cell
terms
anaemia,
Huntington’s
severe
the
in
of
the
disease.
different
viewpoints
disorder,
meanings
health and
Consider
haemophilia.
codominant)
Discuss
your
cultural
answers.
combined
2
Explain,
with
a
named
example
in
immunodeficiency
each
syndrome
case,
why
and
damage
to
the
body
brought
lung
cancer,
by
a
person’s
own
dependency, Type
some
disease
often
influenced
by
lung
cancer,
different
Suggest
behaviour
of
others
a
living
put
them
at
risk
of
conditions,
social
environment
and
a
increase
the
degenerative
developing
vectors
active
(see
puts
likelihood
disease.
page
you
130);
certain
diseases.
There
are
risk
at
risk
of
Some
living
of
catching
an
infectious
in
being
or
infectious
diseases
visiting
Huntington’s
disorder
is
infected.
highly
are
places
disease
or
to
who
those
develop
by
insect
vectors
inherits
the
or
lung
the
allele
biggest
cholera
who
cancer
,
for
risk
are
smokes
but
increases
the
chance
Huntington’s
factors
more
for
to
their
diseases;
spread
risk
much
developing
many
likely
is
that
for
where
of
less
developing
than
the
example,
there
and
are
are
be
a
both
risk factor for
Illustrate
your
with
diseases
that
occur
the Caribbean.
the
4
List
as
List
some
many
diseases
as
you
can.
are
categories
of
disease
allele
than
those
given
in
the
condition.
chronic
person
condition.
to
diseases.
table. Try
Someone
poverty,
developing
transmitted
where
Someone
likely
a
lifestyle
factors
other
for
non-
occupation
in
that
of
dependency
answer
can
categories
why
western
many
behaviour
,
List
disease.
considered
People’s
diseases
drug
b
social
infectious
non-infectious.
diabetes
3
social
as
as
2
infectious
actions
are
drug
five
about
diseases
(SCID)
categorised
self-inflicted
some
who
Poverty
is
water-borne
insanitary
bronchitis
inherits
one
of
the
diseases
like
diseases
about
categorising
you
have
different
medicine
compile
may
your
all
the
listed. Thinking
branches
help
you
of
to
lists.
conditions.
129
1.2
Dengue fever
Dengue
Learning outcomes
and
On
completion
of
this
section,
you
is
in
on
the
spread.
should
be
able
fever
other
name
the
an
Some
infectious
of
increase,
the
both
facts
disease
world.
in
about
It
terms
is
of
dengue
that
is
common
considered
number
fever
are
of
an
in
the
Caribbean
emerging
cases
and
summarised
its
in
disease
as
it
geographical
the
table.
to:
Infectious

is
parts
causative
agent
diseases,
like
dengue
fever
,
that
are
always
present
in
a
of
population
are
said
to
be
endemic.
Dengue
fever
is
endemic
in
the
dengue fever
Caribbean

state
that
aegypti,

is
describe
the
the
the
mosquito,
vector
of
with
outbreaks,
or
epidemics,
dengue
transmission
Causative
agent
four
outline
fever
the
in
of
dengue
Method of transmission
not
with
we
an
the
term
epidemic. Also,
used
ecological
are
is
a
year.
deaths
the
the
to
term
DENV-1,
virus,
DENV-2,
related
tropics
and
4
mosquito
of
Aedes
species
sub-tropics
days
action of
pathogen
white
blood
cells;
liver
and
bone
marrow
see
Clinical features
high fever,
nausea
and
painful
Method of diagnosis
made from
symptoms;
blood
that
body
aches
that
endemic
–
number
health
period
of
reported
in
page
50.
incidence
in the
tests
varies:
region
130 000
show
also
low
(2010);
by
laboratory
white
approx.
cell
count
20 000
(2011)
of
cases
Annual
incidence
Annual
mortality
time:
is
is
the
during
more
worldwide
50–100
million
that
in the
varies:
130
(2010);
worldwide
12 500–25 000
14
(2011)
authorities
week,
a
period
about
this
region
month
number
of
Annual
mortality
of
The
causative
agents
of
dengue
fever
are
a
group
of
related
viruses,
the
in
dengue
Section
–
dengue
endemic
remember
context
Mortality
time. There
and
approximately
period
virus
of
DENV-4
Incubation
Caribbean
or
years.
foc us
reported
during
RNA
and
across
Caribbean
Incidence
an
Global distribution
Annual
S tudy
some
foc us
confuse
have
in
(strains)
vector: female
aegypti
Site of
Do
insect
the Caribbean.
S tudy
is
DENV-3
impact
occur
serotypes
which
of
dengue fever

that
Aedes
fever
viruses
known
as
DENV
.
Each
virus
consists
of
genetic
1.5.
material
in
surround
form
a
from
host
once
the
the
form
RNA
smooth
Dengue
female
a
host
viruses
that
gain
protein
to
stop
blood
for
gut
to
takes
of
structural
the
completely
codes
for
virus;
proteins.
the
surrounds
enzymes
their
of
that
while
are
to
be
They
they
Female
take
a
mosquito,
salivary
blood
an
a
other
lipid
help
to
Capsid
two
proteins
proteins
bilayer
derived
replicate
uninfected
an
is
a
the
meal.
the
and
The
take
While
blood.
after
8
viruses
uninfected
people
vector
anticoagulant
blood
replicate
This
mosquitoes
within
glands.
to
to
aegypti .
inject
transferred
transmitted
another
infected
Aedes
pathogens.
eggs.
the
from
species
mosquito’s
mosquito
mosquito
the
viruses
cells
the
three
core
transmitted
of
clotting
person,
the
transfer
female
are
transmits
to
infected
that
RNA
and
the
virus
cell.
mosquitoes
organism
enter
The
RNA
form
surface
cells.
inside
of
to
blood
in
their
they
The
to
10
by
an
meals
saliva
feed
on
an
viruses
days
remain
person
–
in
when
the
the
meal.
Replication of the virus
Figure 1.2.1
Aedes
aegypti the vector of
dengue fever taking a blood meal
130
When
blood
the
cells
virus
in
enters
the
skin.
the
human
The
virus
body,
binds
it
to
attaches
a
cell
to
the
surface
surface
protein
of
and
white
is
Module
taken
fuses
into
the
cell
with
the
membrane
(capsid
proteins
release
the
reticulum
lumen
many
The
of
RNA,
the
RNA
viral
plus
(RER)
times
and
particles
endocytosis.
which
and
give
the
of
RNA).
where
ER
to
by
is
is
cut
new
by
The
capsid
to
into
a
The
assembled
membrane
from
on
the
within
break
rough
of
to
the
of
virus
the
apart
the
virus
RER
the
is
term
vector
engineering for
liposomes
copied
cells.
See
that
protein
attach
the
to
needed
Golgi
to
body
enter
so
that
new
the
host
cells.
to
make
surrounded
proteins
These
by
4.
1
within
vesicles
to
the
cell
surface
are
where
new
viral
glycosylated.
they
leave
more
white
blood
a
short
by
The
flu-like
high
40 °C

a
rash,

pain
period,
symptoms,
nausea,
in
typically
4
to
7
days,
an
infected
severe
muscles
infected
2
may
online for
the
animations
replication
virus. They
using
this
and
such
as
headache,
high
fever
,
vomiting
with
and
temperatures
is
feel
lost
with
unwell
from
bleeding
dehydration
There
are
people
is
no
swollen
lymph
glands
may
can
likely
drugs
the
dengue
is
usually
ill
for
about
10
to
14
days,
question
longer
plasma
occur
,
to
than
as
this.
Complications
capillaries
for
example
become
into
may
more
set
State
the
meaning
as
a
available,
so
treatment
giving
plenty
the
gut
lumen.
fluids
usually
and
consists
perhaps
and
joint
risk
of
pains.
Aspirin
should
of
be
to
Some
increase
cases
can
haemorrhagic
About
5%
of
the
develop
form,
these
in
the
which
are
applied
to
infectious
such
as
dengue fever.
Explain
how
the
dengue fever
making
is
virus
that
causes
transmitted.
painkillers
used
as
Draw
diagrams
to
show
how
this
virus:
bleeding.
into
cases
terms
Severe
using
not
the
and
result.
of
of
endemic and
in.
permeable
2
occur
muscle
3.
but
dengue
tends
you
to
joints.
for
the
comfortable,
reduce
help
Summary q uestions
3
to
the
description
Summary
diseases
internal
of
as
vector as
Fluid
1.
foc us
emerging disease,
they
in Unit
person
1
Anyone
Module
and
into
symptoms:
painful
as
genes
to
answer

viruses
transfer
cells.
incubation
developing
plasmids,
genetic
viruses
exocytosis
when
starts
in
particles
dengue
After
used
new
showing
infect
of
is
the
Search
pass
biology
replication.
S tudy
envelope
of
Link
The
to
enters
Applications
virus
endoplasmic
DNA
the
RER
core
formed
RNA
similar
the
the
then
protein
The
process
surrounding
releasing
proteins
sections.
in
are
so
ribosomes
translated.
RNA
proteins
coated
membrane
vesicle,
travels
it
The
the
3
more
there
fatal
–
is
severe
and
internal
usually
sometimes
and
external
amongst
young
a
enters
b
is
c
leaves
a
white
blood
cell
fatal
replicated
bleeding.
adults
the
cell
to
infect
and
others.
children.
prompt
People
can
treatment.
also
die
Severe
from
cases
dehydration
are
often
if
treated
they
in
do
not
receive
You
hospitals.
will
need
diagrams
in
to
the
protein
include
organelles
in
your
involved
synthesis.
Prevention
4
Health
the
authorities
vector
of
the
throughout
disease.
the
There
Caribbean
are
specic
direct
prevention
measures
that
can
Explain
why
dengue fever
serious
health
is
a
against
be
problem
in
the
taken,
Caribbean.
such
as
fumigation,
predators
ditches.
of
draining
mosquito
People
bodies
larvae
should
into
avoid
of
standing
water
being
water
courses,
bitten
by
such
and
as
placing
irrigation
mosquitoes
5
A
vaccine for
available

wearing
long
mosquitoes
clothes
tend
to
to
avoid
exposing
skin
during
polio
became
by:
the
day
when
the
reasons
bite
fever
in
the
why
did
a
not
1950s.
Suggest
vaccine for
become
dengue
available
th

putting
up
entering

keeping

using
screens
on
doors
and
windows
to
prevent
in
mosquitoes
houses
areas
houses
tidy
and
free
of
possible
breeding
coils
and
insect
repellents.
Repellents
with
DEET
ingredient
Search
tend
to
be
the
most
effective.
DEET
is
the
annual
of
the
four
and
with
on
for
may
the
page
that
there
types
they
target
3
2012,
an
of
is
odour
enzymes
156).
type,
no
virus
soon
that
be
approved
that
mosquitoes
that
not
vaccine
cause
available.
for
by
any
one
of
dengue
Drugs
replicate
Infection
but
20
actively
the
provide
fever
.
to
treat
virus
strain
the
to
(see
immunity
are
disease
those
provides
website
in
annual
the Caribbean
dislike.
V
accines
the
and
an
region for
As
the
PAHO/WHO
incidence
mortality figures
insecticide
of
as
for
active
half
places
6
the
second
century.
around
mosquito
the
for
natural
to
being
are
HIV
of
tested
likely
in
active
any
to
Question
immunity
How
2010
do
the
last full
these
when
epidemic
countries
in
there
the
are
year.
compare
was
a
with
serious
region? Which
most
at
risk
of
dengue fever?
others.
131
1.3
HIV/AIDS
HIV
Learning outcomes
On
completion
should
be
able
of
this
section,
you
stands
infects
cells
HIV
not
is
between
to:
person.

state
that
human
(HIV)
infection
with
may
lead
to
of
virus


syndrome
the
different
transmission
of
methods
outline
the

HIV
social
of
of
an
system,
virus
and
infected
but
is
it
person
transmission
is
only
not
Like
DENV
,
transmitted
transmitted
and
the
blood
by
of
the
by
a
direct
an
virus
vector
.
contact
uninfected
are:
aspects
of
anal
sex
between
a
person
who
is
HIV+
and
a
person
who
a
needle
someone
or
who
sterilised
by
between
syringe
is
a
not;
that
this
health
is
can
worker
intravenous
used
on
happen
HIV+
when
following
drug
an
use
a
person
needle
or
when
or
a
and
then
syringe
needle
is
is
users
of
blood
in

blood
or
in
shared
the
robust
virus.
uninfected
not
describe
immunodeciency
immune
a
Methods
blood
on
(AIDS)

the
such
vaginal
is
the
acquired
immunodeficiency
of
human
the
immunodeficiency
development
for
from
blood
an
HIV+
products,
person
such
as
is
used
clotting
in
transfusion
factors
used
to
or
is
a
treat
contaminant
haemophiliacs
HIV

across

at
the
placenta
during
pregnancy
transmission

outline
the
life
cycle
of
birth
blood
of
a
HIV+
mother
incubation
period
of
and
the
blood
of
her
baby
mix.
HIV
There
is
flu-like
HIV
outer
when
envelope
is
is
the
a
short
symptoms
a
that
retrovirus.
reverse
of
are
Its
what
often
RNA
is
used
normally
several
weeks.
Then
there
are
mild
misdiagnosed.
as
a
happens
template
in
cells.
to
make
The
DNA,
virus
has
which
surface
glycoprotein
proteins
that
interact
with
proteins
on
the
surface
of
enters
the
T-lymphocytes.
The
transmembrane
virus
fuses
with
the
host
cell
and
the
RNA
cell.
Reverse
glycoprotein
transcriptase
lipid
uses
the
viral
RNA
as
a
template
to
assemble
double-
membrane
stranded
capsid
proteins
RNA
DNA,
which
integrase
attaches
provirus.
It
DNA
is
may
used
as
it
enters
to
host
remain
a
the
DNA.
inactive
template
nucleus
for
This
for
host
where
the
viral
incorporated
several
RNA
years.
enzyme
viral
When
polymerase
to
DNA
is
a
activated,
make
the
complete
protease
RNA
as
the
genetic
material
for
new
viruses,
and
mRNA
to
make
viral
reverse
proteins.
Protease
cuts
the
protein
produced
on
ribosomes
into
short
transcriptase
sections
that
are
assembled
around
RNA
to
make
new
viruses.
These
integrase
travel
Figure 1.3.1
to
the
cell
surface
membrane
and
leave
surrounded
by
host
cell
Human immunodeficiency
membrane
with
HIV
glycoproteins
incorporated.
virus
The
infection
until
the
thrush,
is
then
appearance
tuberculosis,
symptomless
of
a
a
variety
rare
form
of
for
a
fairly
lengthy
opportunistic
of
pneumonia
period
diseases ,
and
of
time,
including
Kaposi’s
sarcoma
(a
Did you know?
rare
form
of
cancer).
T-lymphocytes
At
the
beginning
of
the
in
the
1980s,
people
inherited
disease
decreased
as
develop
they
have
because
been
the
number
destroyed
by
of
Acquired
Immunodeciency
Syndrome
or
AIDS
is
HIV
the
term
with
applied
the
diseases
HIV/AIDS
infection.
pandemic
has
These
to
the
collection
of
opportunistic
diseases
associated
with
HIV
haemophilia
infection.
were
treated
agent
that
with
was
a
blood-clotting
contaminated
with
The
start
HIV. These
people
sadly
rst
of
are
Now
people
provided
produced
with
using
with
AIDS
pandemic
that
as
promoted
were
HIV
identied
spread
in
the
through
early
1980s.
populations
This
was
worldwide.
the
its
spread
The
were:
haemophilia
clotting
agents
recombinant

people

ease
had
unprotected
sex
with
many
partners
DNA.
of
travel
Caribbean
and
from

poor

long
worldwide,
and
migrant
North
e.g.
tourists
workers
from
travelling
North
America
between
visiting
countries
and
America
diagnosis
period
symptoms
132
of
developed
factors
AIDS.
a
cases
of
time
when
people
were
infectious
but
showed
no
the
to
Module

no
cure

the
and
no
3
Applications
response
distributing
and
of
health
appropriate
providing
sex
authorities
information
education
in
and
about
governments
the
the
denial
by
some
transmission
of
HIV
AIDS
HIV/AIDS
sexual
is
and
governments
that
HIV
existed.
the
transmission,
Widespread
but
to
control
Health
they
testing
not
a
single
reasons for
Compare AIDS
of
as
it
is
authorities
cannot
control
populations
for
transmitted
can
primarily
distribute
people’s
HIV
is
sexual
(see
page
also
S tudy
about
foc us
behaviour
.
expensive
Obtain
and
some
leaflets
authorities
organisations
have
term AIDS.
SCID
and TB.
health
that
with
during
information
impractical.
Methods
disease. Work
the
control
difcult
intercourse.
is
schools
156)
Prevention
foc us
in
out

biology
vaccine
S tudy
slow
of
been
employed
by
different
countries
in
the
published
and
working
by
voluntary
with
HIV/
region
AIDS. Assess
the
they
to
information
that
include:

providing
that
people
HIV+

information
should
should
providing
countries

still
testing
the
HIV
those
organisations
AIDS
A
testing
and
to
stigma,
fear
there
a
is
occurs
sex
active
during
in
sex
in
in
Sint
those
Maarten
prison,
through
Cuba
testing
pregnant
as
who
provide
becoming
are
to
live
with
and
condoms
clinics;
clinics
for
in
of
both
at
was
Caribbean
people
if
HIV+,
how
HIV/AIDS.
are
sexually
mandatory
and
providing
with
and
for
awareness
with
HIV
.
prevention
and
national
HIV/AIDS.
Although
women,
example,
and
Partnership
in
individual
men
even
women
activities
associated
for
high
risk
antiretroviral
many
that
support
In
most
is
Against
and
levels,
many
is
the
countries
transmission
associate
illegal.
groups
HIV/
control.
have
HIV
Some
with
people
been
killed.
antiretroviral
those
and
many
drugs
(AR
Vs)
has
improved
the
life
Figure 1.3.2
expectancy
prevent
infected
HIV+
Pan
Jamaica
against,
of
in
the
between
HIV/AIDS
provision
of
associated
men;
discriminated
The
hatred
that
precautions
others
the
distributed
coordinate
problem,
and
example
and
the
some
status
as
HIV/AIDS,
(STIs)
identied
such
stigma
between
for
of
infection
schools,
centres;
is
(PANCAP)
widespread
are
risks
infecting
for
high
the
avoid
avoid
infections
groups
drugs
to
condoms,
condoms
voluntary

to
through
transmitted

take
take
free
distributed
about
living
with
HIV/AIDS
and
helped
to
reduce
the
HIV/AIDS awareness
death
campaigns stress the importance of using
rates.
Provision
received
these
varies
drugs;
between
in
countries.
Jamaica
it
was
In
Cuba
about
in
2010
all
patients
condoms during sexual intercourse to
reduce the chances of transmission of HIV
50%.
Summary q uestions
1
i
State
ii
State
AIDS
what
is
which
and
meant
by
categories
justify
your
HIV
of
and AIDS.
disease
apply
to
5
Identify
6
Contrast
the
Describe
of
the
the
virus
transmission
may
be
Explain
HIV+,
the fact
but
not
Make
a
table
information
risk
of
HIV
infection.
the
response
of
HIV
and
how
the
epidemic
of Cuban
with
the
authorities
responses
of
to
the
other
countries.
spread
controlled.
that
someone
can
be
diagnosed
Suggest
vaccine
as
why
to
it
has
protect
so far
proved
against
difficult
to
develop
a
HIV.
have AIDS.
8
4
at
HIV/
7
3
most
choices.
HIV/AIDS
2
people
similar
about
to
that
on
page
130
to
summarise
Outline
the
ways
in
which
HIV/AIDS
differs from
dengue fever.
HIV/AIDS.
133
1.4
Diabetes
Learning outcomes
and
cancer
Diabetes
Diabetes
On
completion
of
this
section,
be
able
state
that
diabetes
and
both
not
degenerative,
are
two
explain
T
ype
1,
1
the
difference
and Type
outline
the
T
ype
2,
2
risk factors
discuss
2
the
awareness
seeking
and
do
not
disease
respond
or
in
which
respond
poorly.
by
usually
develops
pancreatic
early
in
life
in
which
no
insulin
is
β-cells
which
diabetes
and
importance
of
develops
later
in
life
and
is
usually
associated
with
a
of
risk
factors,
including
diet
and
obesity
2
diabetes
in
the
the
more
Caribbean
common
and
form
elsewhere.
and
is
Some
a
serious
people
health
have
it
for
a
long
cancer
before
they
seek
a
diagnosis
of
symptoms,
such
as
these:
of
symptoms
treatment for
is
associated
time

degenerative
cells
diabetes
problem
with Type
target
between
T
ype

its
types:
which
variety
Type
non-infectious,
or
diseases


a
non-
secreted
infectious
is
secreted
cancer

are
is
to:
There

mellitus
you
insulin
should
mellitus

feeling
very

extreme

itchiness

recurring
thirsty;
urinating
a
lot,
especially
at
night
and
cancers
diabetes.
the
tiredness;
around
weight
the
infections
growth
of
this
loss
vagina
of
with
or
Candida
yeast-like
loss
of
muscle
tissue
penis
causing
fungus
is
the
disease
promoted
known
by
as
glucose
thrush;
in
the
urine
Link

You
studied
aspects
of
blurred
in Unit
1.
See
4.3
of
in Unit
1. Another
type
of
factors
diabetes
insipidus
–
see
this
that
Prenatal
page
the
be
promote
the
malnutrition .
famine
have
because
‘thrifty
Genetics .
family
onset
Studies
a
higher
prenatal
phenotype’
Diabetes
members
themselves.
S tudy
the
eyes
becoming
glucose
is
diagnosed
tolerance
done
Summary
and
by
test.
then
question
using
Find

a
out
Native
how
answer

7
.
of
T
ype
2
have
Age .

researchers
cannot
controlled
also
In
that
of
people
diabetes
whose
than
mothers
others.
predisposes
to
obesity
This
thanks
to
in
which
fat
to
in
T
ype
alone
run
2
are
is
diabetes
not
stored
in
families,
are
at
times
and
risk
responsible:
of
diet,
the
effects
lack
Diet .
A
USA,
does
is
diet
Obesity .
more
not
to
high
the
Greater
a
high
Americans,
prevalence
common
secrete
experiments
on
to
fat,
of
and
in
insulin
older
as
T
ype
people.
efciently
2
It
of
interferes
conditions
have
an
years from
Some
have
been
carried
is
thought
target
cells
with
not
enough
bre,
and
much
rened
increases
with
the
Fat
were
born
during
or
Holland
sugar
the
risk
that
target
cells
do
not
body ’s
ability
to
10
seconds
from
a
person
diabetes.
insulin.
High
blood
pressure
and
high
blood
the
2
same
people
10
seconds,
after
develop
disease.
to
studies
people
shortly
in
the
become
tissue
dies
use
generation
on
that
and
impact
long-term
out
and
diabetes.
diabetes.
bulk
insulin.
cholesterol.
in
it
exercise
Hispanic-Americans
of
the
famine
of
easily

many
have
insulin.
in
risk
African
have
In
malnutrition
generation.
plenty.
who
developing
Every
people;
of
those
important.
the
responsive
respond
conduct
Genes
Diabetes
increases
Did you know?
over
dry.
diabetes:
found
prevalence
malnutrition
tends
with
Americans
pancreas

Medical
are
Ethnicity .
less
like
very
foc us
obesity
Diabetes
is
in
unit.

this
lenses
118
may
of
the
diabetes
suffered
is
by
Module

2
caused
diabetes
Risk
mellitus
vision
who
the
coronary
diet,
These
arteries
obesity
increase
the
two
and
and
lack
risk
of
factors
together
of
damage
with
exercise,
diabetes.
1944–45.
T
reatment
involves
Later
it
for
T
ype
careful
may
2
diet
become
diabetes
control
usually
and
necessary
exercise.
to
take
Figure 1.4.1
insulin.
Awareness of diabetes
is highlighted each year on 14
November – World Diabetes Day
134
Module

Cancer
T
esticular
testes.
Cancer
is
parts
the
a
group
of
diseases
that
affect
body.
Each
one
arises
from
a
single
grows
uncontrollably
to
for m
a
tumour.
such
caused
Breast
by
mutations
in
genes
that
control
and
division.
Not
all
tumours
are
are
either
malignant
or
benign.
Cancers
place
tumours
where
they
as
the
arise
cells
and
may
invade
may
migrate
via
lymphatic
spread
from
adjacent
vessels
to
areas
remote
in
the
body.
breasts.
as
for med
the
in
body
other
(metastatic)
is
metastasis
parts
of
the
agents,
factors
Further
are
factors
proliferation
a
of
or
that
of
to
both
cancer
cells
by
cancer:
Lung
(see
page

cancer:
and/or
to
countries
at
risk
early
DNA.
mitosis.
substances
so

Environmental
hazards:
ionising
chemicals
(e.g.
radiation,
dioxins,
Food
organisations
longer
There
have
is
nitrites
in

red
with
that
meat
toxin
in
are
by
of
viruses
carcinogens
processed
processed
meat
These
to
several
cancer:
(HPVs)
Human
the
breast
vaginal
vaginal
or
cough;
cancer
as
bleeding,
e.g.
discharge
pain
that
during
coughing
up
sex.
blood;
pains.
have
mass
screening
programmes
for
cancers.
of
is
very
cancer
.
and
is
effective
Cervical
cancer
for
checking
by
taking
the
detecting
of
cancerous
laser
for
treatment.
of
the
signs
important
the
are
X-rays
images
is
at
smears
signs
destroyed
involves
Mammography
lumps
Failure
to
cannot
check
help
treatment
of
be
a
cure.
It
for
of
a
because
40%
felt.
symptoms,
reduces
also
may
or
the
have
chances
lengthens
be
the
necessary
T
reatment
radiotherapy
and
may
of
screening
time
and
for
reduces
involve
or
seek
successful
which
the
chances
chemotherapy,
surgery.
be
added
as
S tudy
foc us
formation
botulinum
viruses
are
no
foods.
may
are
prevent
Chlostridium
shoulder
screening
The
treatment.
regulatory
nitrosamines
cancer
.
with
development
cervical
use
that
and
by
potential
the
certain
benzpyrene)
safety
colourings
Infection
(papilloma)
for
gastric
and
for
any
evidence
with
botulinum
Viruses.
tested
approval
preservatives
of
so
some
associated
are
get
discomfort
cells.
medical
additives
of
examine
(in
carcinogenic.

a
microscopically
breasts
light
X-rays,
asbestos,
abnormal
periods;
examined
of
sunlight),
men
persistent
Mammography
174).
ultraviolet
of
stages
tumour
.

that
unpleasant;
Cervical
the
of
Note
normal
Some
are
damage
groups
to
spreading
secondar y
promote
damaged
contains
cause
cause
one
tumours
carcinogens ,
required
these
smoke
potent
are
in
how
women.
between
those
environmental
is
body
the
lump
learn
blood
cancers.
Cancer-causing
T
obacco
the
and
should
Cervical
chest
through
painless
tissues.
or
This
a
Women
the

stream
the
lumps.
cancer:
smells
They
on
regularly
are

malignant
lumps
testes
cancers;
well
they
their
cell
their
growth
painless
examine
biology
Cancers
breasts.
are
unusual
should
of
cell

that
Applications
different
for
of
cancer:
Men
3
is
Cancer
is
linked
wart
main
not
can
cause
is
often
the
thought
case. This
affect
younger
to
be
section
‘a
disease’
of
concentrates
old
on
age,
which
cancers
that
people.
of
cancer
.
Summary q uestions
Liver
cancer
infection
with
the
may
with
develop
hepatitis
Epstein-Barr
B
after
and
virus
leukaemia/lymphoma
many
C
and
virus
years
viruses.
the
of
Infection
1
T-cell
risk
of
blood
cancers.
(HTLV-1)
HIV+
risk
Kaposi’s
of
blood
cancers
and
the
difference
between Type
1
and Type
2
increases
people
are
Outline
rare
the factors
that
influence
the
development
of
at
Type
greater
the
diabetes.
2
the
Explain
2
diabetes.
cancer
,
3
sarcoma.
Define
the
terms
tumour,
cancer, mutagen,
carcinogen.

Genetic
more
factors .
often
in
population.
BRCA1
and
percent
of
alleles
BRCA2
breast
inherited
types
families
Mutations
all
are
Certain
some
in
are
either
linked
cancer
in
a
of
cancer
than
in
of
to
the
The
dominant
rest
of
the
4
genes
about
cases.
occur
the
ve
Explain
the
be
aware
5
Outline
the
benign
6
Explain
the
risk factors for
cancer.
how
people
can
reduce
their
risks
of
fashion.
7
of
and
mutant
awareness
should
malignant
ten
Find
out
Sketch
People
between
tumours.
to
developing
Symptom
difference
symptoms
of
cancer
,
a
how
Type
a
graphs
2
diabetes,
glucose
to
show
and
tolerance
what
you
b
cancers.
test
is
would
carried
expect
out.
to find
as
in:
early
diagnosis
tumours
damage
four
can
and
be
other
treatment
removed
tissues.
often
before
Here
are
means
they
some
that
spread
and
symptoms
of
a
a
b
someone free
person
with Type
of
2
the
diabetes
disorder.
cancers:
135
1.5
Health
statistics
How
Learning outcomes
should
outbreak
On
completion
should
be
able
of
this
section,
you
with
rst
to:
explain
the
differences
is
and
mortality
incidence
in
Haiti
about
is
in
the
of
the
2010
or
to
the
Caribbean?
accurate
some
respond
data
about
different
emergencies,
increasing
Before
the
health
such
number
responding,
diseases
as
of
one
concerned.
statistics
that
are
the
people
of
the
This
collected,
between
and
published
by
organisations,
such
as
CAREC,
PAHO/WHO
and
and
between
authorities
throughout
requirements
collated
morbidity
cholera
diabetes
section

of
medical
the
UN.
and
prevalence
Morbidity data

explain
the
calculating
importance
rates
of
of
incidence
and
mortality
Morbidity
diseases.
records.

analyse
main
and
interpret
indicators
of
data
health
on
data
This
and

data
incidence
–
particular
1.5.1

the
is
the
shows
how
many
people
come
expressed
have
from
certain
doctors’
illnesses
records
and
and
hospital
as:
number
the
of
of
time
–
incidence
2006
in
prevalence
–
or
certain
the
El
new
cases
usually
of
a
diagnosed
week
dengue
or
fever
a
and
reported,
month
from
or
January
a
over
year;
2005
a
Figure
to
Salvador
number
of
people
with
a
disease
at
a
particular
time
foc us
within
change
of
us
morbidity
period
December
Most
on
the
disease.
S tudy
tells
Details
Summary
questions
a
in
time
prevalence
of
period,
e.g.
HIV/AIDS
a
in
year;
the
Figure
1.5.2
Caribbean
shows
from
the
1990
to
on
2010.
pages
data
140
in
to
141
are
these four
based
on
the
pages.
2500
Before
answering
graphs,
to
take
right,
where
on
noting
an
the
run
trend
paper,
significant
troughs,
on
it from
or
mark
occurs
plateaux,
1500
etc.
1000
fo
peaks,
and
exam
anything
as
questions
ruler
sesac
pattern;
such
a
2000
fo
left
foc us
revef eugned
S tudy
rebmun
S tudy
500
foc us
0
For
more
information
about
HIV/
J
AIDS
see
the
websites
of
Figure 1.5.1
following
organisations:
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
the
Monthly incidence of dengue fever in El Salvador 2005–2006. The rainy
PANCAP,
season runs from May to October.
Avert,
PAHO, WHO.
T
able
1.5.1
second
Did you know?
2010.
There
fever
and
were
in
epidemics
of
the Caribbean
2010.
Search
in
2005–06
online for
This
region.
dengue
slow
down
about
these
will
help
and
with
the
page
Summary
question
of
the
the
on
involving
living
health
can
be
infection
AIDS
region
the
ser vices
provided
and
patients
taking
of
with
several
TB,
dr ugs
with
throughout
with
control
have
world
HIV/AIDS
dr ugs
the
in
the
that
the
which
over
a
itself
is
long
of
time.
Over
with
the
time,
the
number
HIV/AIDS
of
new
epidemic
cases
falling
peaked
steadily
in
the
since
then.
1
from
AIDS-related
diseases
140.
fallen
136
treat,
impact
Many
is
population
HIV/AIDS
development
to
the
summary
Deaths
on
with
infections.
disease
mid-1990s,
questions
Caribbean
of
epidemics. This
period
research
the
considerable
living
the
opportunistic
news
that
proportion
has
People
dif cult
reports
shows
highest
since
the
mid-2000s.
peaked
10
years
later
and
have
a
Module
Applications
of
biology
snoillim
300
150
ni
upper
estimate
lower
estimate
200
elpoep
150
fo
100
rebmun
50
0
0102
9002
8002
7002
6002
5002
4002
3002
2002
1002
0 00 2
9991
8991
7991
6991
5991
4991
countries
a
3991
Prevalence of HIV in the Caribbean: the number of people living with HIV 1990–2010
T
obago,
with
2991
The
1991
0991
Figure 1.5.2
and
3
in
the
Jamaica
great
deal
of
region
and
with
the
the
highest
Dominican
uncertainty;
quite
prevalence
Republic.
frankly
no
All
one
of
HIV
quoted
knows
are
Haiti,
gures
the
for
exact
the
Bahamas,
prevalence
size
of
the
are,
Guyana,
Suriname,
however
,
HIV/AIDS
estimates
T
rinidad
made
pandemic.
Table 1.5.1
Region
HIV/AIDS
among
children
Incidence/numbers of
new
cases
in
and
adults
Prevalence
in
Numbers of
Sub-Saharan Africa
Middle
East
Eastern
and
Europe
Western
1
and Central
22 900 000
5.0
59 000
470 000
0.2
270 000
4 000 000
0.3
30 000
840 000
0.2
58 000
1 300 000
0.6
12 000
200 000
0.9
100 000
1 500 000
0.4
3300
54 000
0.3
88 000
790 000
270 000
4 000 000
Caribbean
Oceania
South
Figure
and
South-East Asia
1.5.3
shows
the
Percentage of total
900 000
North America
East Asia
and
adult
Europe
Latin America
adults
children
North Africa
and Central Asia
2010
2010
population
0.
1
0.3
4
10
progress
of
the
HIV/AIDS
Caribbean
in
the
total
people
as
have
of
been
having
AIDS
latoT
country.
in
Dominican
Republic
10
sesac
each
changes
number
who
recorded
in
as
3
dedrocer
countries,
Caribbean
SDIA fo rebmun
epidemic
Bahamas
Jamaica
2
Cuba
10
Bermuda
St Vincent
and
Grenadines
1
10
Dominica
Turks
10
Virgin
and Caicos
Islands
(UK)
Anguilla
1
1978
1982
1986
1990
1994
1998
2000
Year
Figure 1.5.3
137
Module
3
Applications
of
biology
Table 1.5.2
Country
T
able
1.5.2
adult
populations
gives
estimates
of
some
of
the
prevalence
Caribbean
of
diabetes
amongst
the
countries.
Prevalence/
percentage of
The
adult
late
population
data
in
1980s
the
and
table
was
1990s.
If
collected
repeated
from
now
samples
the
of
gures
populations
would
all
in
likely
the
be
higher
.
Barbados
16.4
Cuba
Mortality data
11.8
Details
Guadaloupe
on
mortality
come
from
the
information
recorded
on
death
5.8
Jamaica
certicates.
When
people
have
who
collated,
died
and
this
information
what
they
have
tells
died
us
about
from.
the
number
However
,
of
doctors
12.6
are
Suriname
not
people
8.7
that
Trinidad
12.7
and Tobago
always
die
of
make
sure
them
factor
had
such
diseases
T
able
to
1.5.3
has
to
as
save
gives
been
the
although
susceptible
contributory
certicates
what
pneumonia,
their
to
pneumonia
on
Many
and
have
and
who
may
members
from
of
have
died
Many
their
and
elderly
conditions
been
of
a
major
AIDS
recorded
of
diabetes
death.
long-term
have
tuberculosis
to
mortality
cause
may
pneumonia
deaths.
embarrassment
data
actual
they
on
have
their
death
family.
all
causes
in
four
Did you know?
Caribbean
mortality
Outbreaks
of
disease
are
on
a
large
across
Pandemics
scale,
are
affecting
continents
or
rate
is
world.
In
the
people
across
past
assess
standardised
the
to
relative
permit
importance
comparisons
of
a
disease
between
the
years
and
countries
and
regions
(see
Summary
question
3
on
page
141).
epidemics
Table 1.5.3
the
Parameter
whole
T
o
called
between
epidemics.
countries.
there
Aruba
Belize
Cuba
St. Vincent
and
have
the Grenadines
been
and
pandemics
cholera. We
of
bubonic
are
plague
currently
in
the
Deaths from
middle
that
of
the
began
in
HIV/AIDS
the
early
diabetes
(all
causes)
pandemic
1980s.
Males
14
(278)
38
(649)
Females
21
(216)
89
(457)
Population
817
(36 814)
1283
(26 135)
16
(341)
18
(260)
(thousands)
Males
48
153
5673
53
Females
53
149
5710
51
Health
the
statistics
number
whole
area.
For
is
area
only
for
or
of
it
be
who
such
workers.
rates.
Incidence
population
may
women
diseases,
as
the
as
They
part
are
at
some
are
of
at
is
risk.
the
risk
may
population
of
diseases,
population
at
risk,
for
be
in
developing
respiratory
the
calculated
This
the
an
cervical
only
not
the
population.
in
includes
Haiti,
an
it
groups
expressed
reported
of
example,
1.5.4
cancers
often
Occupational
certain
general
T
able
are
cases
population
cancer
.
affect
of
shows
26
all
of
annual
countries
Caribbean
Guatemala
standardise
the
the
the
and
death
and
mortality
in
the
Central
Nicaragua.
rates
(see
in
2008
WHO
American
Population
Summary
for
the
Americas
ve
countries
data
4
which
except
allows
question
leading
region,
on
you
page
Cuba,
to
141).
Did you know?
The
last
medical
case
138
smallpox
photographer
laboratory
from
of
and
smallpox.
in
died from
transmitted
naturally
Birmingham, UK,
the
disease
in
was
tragically
1978. This
in
Somalia
caught
was
the
in
the
last
1977
. A
virus
in
known
a
death
Module
3
Applications
of
biology
Table 1.5.4
S tudy
Total
Annual
foc us
mortality
When
population
All
Organ-specific
discussing
the
prevention
and
cancers
control
(thousands)
of
diseases,
do
not
just
causes
consider
Breast
Cervix
Colon
Lung
can
take,
taken
Males
also
235 894.25
1 574 755
121
0
16 812
precautions
that
individuals
Stomach
36 809
at
by
but
the
also
those
that
community
health
are
level
and
authorities,
26 236
governments
and
governmental
inter-
organisations.
Females
242 163.65
1 256 277
33 055
25 592
17 546
17 930
16 236
Did you know?
Prevention
and
control
One
Collection
of
data
is
essential
if
we
are
to
follow
trends
over
time.
of
the
modern
example
in
Figure
1.5.4
shows
the
eradication
of
smallpox
from
India
whole
successes
of
medicine
is
the
eradication
and
of
the
great
The
smallpox. The WHO
declared
the
world.
world free
This
was
of
this
largely
disease
due
to
in
1980.
many
young
500 000
people
who
volunteered
to
carry
India
450 000
out
world
surveillance for
vaccinate
people
at
the
disease
and
risk.
400 000
350 000
sesac
300 000
fo
rebmun
250 000
200 000
150 000
100 000
50 000
0
1950
1955
1960
1965
1970
1975
1980
year
Figure 1.5.5
Figure 1.5.4
Ali Maow Maalin, the last
person to have smallpox that was
The eradication of smallpox. Number of cases of smallpox in India and the
transmitted naturally
whole world between 1950 and 1980.
Summary q uestions
1
Define
the
terms
prevalence,
2
Explain
is
epidemic,
why
usually
morbidity,
the
data
expressed
mortality,
5
incidence,
pandemic
collected
data
on
per 100 000
Discuss
health
of
the
and
disease
population.
6
All
the
Explain
why
rates
of
incidence,
prevalence
rather
4
are
often
than for
Discuss
the
national
the
expressed for
whole
reasons
and
why
the
diseases
are
could
such
of
about
be
of
as
collecting
those
health
to
included
statistics
diseases.
collected
and
Suggest
measure
publishing
in
given
some
the
this
in
section.
this
statistics
health
of
the
and
peoples
mortality
importance
examples
section
that
3
on
the
of
the Caribbean.
population at risk
population.
the
international
statistics
published
organisations
may
by
not
be
accurate.
139
1.6
Summary
questions
Answering
statistics.
health
Y
ou
issues
examiners
your
1
questions
also
in
will
need
the
to
will
nd
Caribbean
expect
you
help
to
and
and
have
you
read
in
to
analyse
and
information
the
rest
up-to -date
of
the
interpret
about
world.
information
health
current
The
to
illustrate
answers.
Use
a
these
Figure
i
1.5.1
Describe
in
answering
the
incidence
these
of
questions.
dengue
fever
in
El
Salvador
in
2005–06.
Figure 1.6.1
ii
Explain
the
pattern
iii
Explain
the
advantage
you
have
described.
A health worker in Cuba
fumigating a house with insecticide to kill
mosquitoes during an epidemic of dengue
weekly
or
monthly
of
recording
rather
than
incidence
from
dengue
fever
annually.
fever
b
i
Suggest
other
need
order
in
shown
S tudy
foc us
ii
in
Outline
the
how
incidence
Developing
vaccines for
dengue
experimental
virus
are
that
used
may
to
make
an
strains
would
be
there
and
against
infection
much
in
an
is
animals;
culture
protection
other
as
infects
difficult
that
it
be
the
that
relative
the
health
authorities
importance
of
the
might
changes
graph.
health
authorities
dengue
should
respond
to
the
changing
fever
.
Explain
the
difference
between
acute
and
chronic
diseases ,
with
animals
reference
cannot
statistics
assess
is
c
difficult;
of
health
to
no
the
it
one
by
more
to
dengue
fever
and
diabetes.
similar
d
Assess
e
Compare
the
impact
of
dengue
fever
in
the
Caribbean.
viruses
is feared
one
of
severe
disease
the
than
the
incidence
strain
2
unvaccinated
Use
a
–
Figure
i
in
1.5.2
ii
b
Suggest
Explain
in
c
Explain
why
prevalence
data
the
in
the
Caribbean
another
with
the
insect-born
WHO.
questions.
1990
pattern
Figure
in
–
prevalence
between
for
of
these
in
fever
malaria
region
changes
region
the
for
dengue
from
answering
reasons
why
estimates
African
the
Caribbean
of
mortality
the
Describe
person.
incidence
and
of
and
you
1.5.2
HIV/AIDS
in
the
2010.
have
described.
includes
upper
and
lower
HIV/AIDS.
prevalence
data
for
data
dengue
for
HIV/AIDS
fever
.
(Refer
to
is
more
Figure
useful
1.5.1
in
than
your
answer
.)
The
mortality
around
Figure 1.6.2
d
The Pan American Health
Organization coordinates the activity of
2005
Explain
rate
and
why
for
has
the
HIV/AIDS
fallen
trend
in
the
Caribbean
reached
a
peak
since.
for
mortality
differs
from
that
for
prevalence.
health authorities throughout the
e
Use
the
information
in
T
able
1.5.1
to
compare
the
HIV/AIDS
Americas, including the fight against
epidemic
in
the
Caribbean
with
other
regions
of
the
world.
malaria in Suriname. Here a laboratory
worker tests blood samples for signs of the
f
Use
the
PAHO
website
and
others
to
assess
the
impact
of
HIV/
malarial parasite.
AIDS
3
a
in
Suggest
the
why
the
Caribbean
1.5.2.
Assess
region.
140
different
countries
in
the
prevalence
of
diabetes
is
the
likely
to
be
Caribbean.
higher
importance
of
in
than
diabetes
the
the
for
adult
gures
population
given
populations
in
in
in
T
able
the
Module
Use
the
information
answering
parts
b
in
and
T
able
1.5.3
5
when
a
i
Describe
cases
c.
ii
b
i
Calculate
the
Suggest
deaths
from
diabetes
as
a
percentage
deaths
mortality
in
each
rate
100 000
mortality
the
for
number
in
the
of
Figure
pattern
1.5.4.
you
described.
Explain
why
as
the
deaths
from
all
had
WHO
been
could
be
eradicated
certain
when
it
that
made
causes
statement
to
that
effect
in
1980.
population
b

in
shown
biology
country
its
per
as
explanations
smallpox

changes
smallpox
of
of
iii
all
the
Applications
following:
have

of
3
rate
from
diabetes
per
Read
about
the
WHO
campaign
to
eradicate
100 000
smallpox
and
summarise
the
reasons
for
its
population.
success.
ii
Use
the
the
results
countries
of
in
your
order
calculations
for
the
two
to
put
to
(There
eradicate
is
more
infectious
about
other
diseases
on
campaigns
page
153.)
mortality
6
Use
Figure
1.5.3
in
answering
these
questions.
rates.
iii
Present
the
data
calculations
c
i
State
the
data
authorities
the
four
ii
from
one
that
might
of
the
table
and
a
your
Describe
international
to
from
assess
diabetes
the
over
b
health
each
next
c
20
Suggest
to
shown
and
why
an
authority
like
this
such
a
long
time
span
progress
the
reasons
in
give
for
some
what
in
of
the
HIV/AIDS
Caribbean.
is
the
likely
Figure
to
1.5.3
reasons
faster
countries
for
progress
than
happen
over
your
the
of
the
others.
to
the
next
patterns
20
years
suggestions.
should
d
consider
in
epidemic
likely
the
Suggest
of
years.
Explain
the
epidemic
table.
collect
countries
importance
30
in
with
Outline
the
impact
that
the
HIV/AIDS
this
epidemic
has
had
on
countries
in
the
disease.
Caribbean.
iii
Outline
the
steps
that
health
authorities
7
should
take
to
combat
the
increase
Dene
some
diabetes
in
the
The
WHO
analyses
risk
data
by
country
and
also
others
Use
the
information
from
T
able
1.5.4
this
i
Use
we
Explain
can
do
why
there
something
are
about
that
refer
to
we
can’t
diabetes,
do
anything
dengue
about.
fever
,
Y
ou
HIV/AIDS
the
cancers
listed
on
page
135
in
your
answer
.
question.
8
a
factor
.
that
to
and
answer
risk
by
should
region.
term
factors
Caribbean.
and
4
the
in
the
data
in
the
table
to
How
that
mortality
rates
per
100 000
does
income
influence
the
types
of
diseases
calculate
for
males
people
have
and
die
from?
and
9
T
o
what
extent
does
occupation
put
people
at
risk
females:
of

for
each

for
all
developing
Read
about
the
data
in
the
table
and
the
present
of
your
calculations
Explain
the
calculations
on
b
different
i
Describe
ii
Make
data
iii
like
these
Outline
one
of
have
when
the
patterns
offer
three
plan,
in
the
mortality
observations
explanations
studies
that
for
the
each
one.
based
on
the
2010
some
data
on
the
This
epidemic.
should
by
about
the
eradication
and Wellcome Trust
research
the
likely
causes
of Type
2
diabetes
you
looking for
such
information
foc us
epidemiologists
observations
made.
the WHO
include
S tudy
and
on
of
ndings.
rates.
about
of
websites.
up-to-date
associations,
American
can find
outbreak
your
data
Link
smallpox
on
out
analysing
diabetes
You
cholera
based
table.
carrying
You
could
Haitian
report
diseases.
signicant
and
in
advantages
a
results
should
iii
the
causes.
and
Present
diseases?
cancer
10
ii
different
as
the Centers for
the Caribbean
obesity
such
Food
information
and
and
about
diabetes
as
do
provided
Diabetes UK
Diabetes Association.
as WHO,
provide
summaries
Health
and
in
Institute,
degenerative
news
national
the
organisations,
Disease Control
Nutrition
by
the USA
also
diseases,
such
as
media.
141
3
Applications
2.
1
Defence
against
or
completion
should

be
dene
able
the
of
this
section,
you
terms
parasite
and
outline
the
infectious
defences

viruses,

bacteria
against

describe
the
non-specic
specic
differences
responses
responses
to
e.g.
,

fungi,
infection.
worms,
prions
agents
are
some,
like
to
see
Viruses
and
as
have
they
hookworms,
with
prions
no
in
gain
these
harm
different
live
to
nutrients
in
the
a
sort
host
and/
of
are
forms:
Epstein-Barr
cholera
tetani
(cholera),
Mycobacterium
tuberculosis
(tetanus)
Plasmodium
Candida
e.g.
albicans
Schistosoma
americanus
(infectious
have
virus
are
or
falciparum
(malaria),
T
rypanosoma
cruzi
(thrush),
Pneumocystis
jiroveci
a
mansoni
(schistosomiasis
or
bilharzia),
(hookworm)
proteins),
variety
of
e.g.
ways
CJD
in
(Creutzfeldt-Jakob
which
they
can
enter
Disease).
is
injected
by
a
mosquito;
HIV
enters
via
the
body.
blood
the
are
cells
naked
not
and
through
sexual
contact.
Other
pathogens
are
to
blood
transmitted
via
large
droplets
enough
of
cause
and
microorganisms
contact
but
host
Many
that
come
a
of
Dengue
Most
on
disease)
e.g.
Pathogens
disease.
or
(pneumonia)

causative
those
HIV
,
Vibrio
in
organism.
but
pathogens
Clostridium
e.g.
live
diseases
between
and
foc us
are
host
DENV
,
e.g.
that
host,
Human
Necator
Pathogens
the
the
protoctista,

S tudy
from
with
(Chagas

organisms
protection
harmony
(TB),
diseases
infectious
are
pathogens.
to:
pathogen

biology
Parasites
Learning outcomes
On
of
in
the
air
and
also
in
food
and
water
.
eye.
organisms
There
are
three
main
types
of
defence
against
infectious
diseases:
no

mechanical
–
tissues
provide
physical
barriers
that
pathogens
cannot
metabolism.
pass

through
chemical
–
unaided
substances
environments
them
for
secreted
pathogens,
reproducing
and/or
by
trap
the
body
them,
growing,
stop
provide
cause
them
inhospitable
them
to
entering
burst,
cells
stop
and
kill
them

cellular
–
presence
to
protect
Details
Once
in
Figure 2.1.1
cells
of
of
the
these
pathogens
spaces
secrete
hormone-like
pathogens;
body
against
defences
gain
between
ingest
are
entry
cells
or
the
in
to
and
to
alert
pathogens;
spreading
the
of
the
body
secrete
to
the
chemicals
pathogens.
table.
tissues,
enter
chemicals
digest
cells.
blood
or
Worms
lymph
can
live
they
in
either
the
gut,
remain
reducing
Transmission of diseases,
especially water-borne diseases, is much
more likely following catastrophes such as
the
quantity
nutrients
of
from
digested
the
food
plasma.
we
absorb
Most
of
or
the
in
the
blood,
pathogens
that
absorbing
enter
cells
enter
the Haitian earthquake
specic
of
the
both
S tudy
often
foc us
about
pathogens
all
the
enter
ways
the
in
body.
groups
of
these
and
then
are
question
Make
a
system
as
itself.
pathogens,
destroying
non-specic
Non-specic
M.
tuberculosis ,
There
but
the
are
defences
removing
infected
defences
and
DENV
them
host
that
from
and
are
HIV
enter
effective
cells
is
cells
against
difcult
and
cells.
specic
defences
against
pathogens.
defences
different
are
present
pathogens
and
from
they
birth,
give
the
they
do
same
not
distinguish
response
each
time
answer
pathogen
enters
the
1.
not
142
such
which
particular
Summary
of
involves
between
list
Some,
defence
There
Think
cells.
always
highly
effective.
body.
They
usually
act
very
fast,
but
are
a
Module
Defence
Mode of
action
Sites
3
Applications
in the
of
biology
body
Mechanical:
skin
epidermal
physical
mucous
membranes
cells,
cells
with
keratin
provide
a
tough
skin
barrier
e.g.
goblet
cells,
secrete
mucus
to
trap
trachea,
pathogens
vagina,
bronchi,
bronchioles
gut
Chemical:
lactic
acid, fatty
hydrochloric
acids
provide
inhospitable
environment
with
low
pH
skin,
acid
vagina
stomach
histamine
hormone-like
action
to
stimulate
interferon
hormone-like
action
to
protect
interleukins
hormone-like
actions
to
cellular
cells
regulate
defences
against
the
viruses
immune
most
tissues
most
tissues
blood,
lymph
and
most
tissues
blood,
lymph
and
most
tissues
system
complement
proteins
from
antibodies
that
the
aggregate,
toxins;
help
mark
and
remove
pathogens
body
immobilise
prevent
entry
and
of
kill
pathogens;
pathogens
into
neutralise
blood
and
lymph
cells
Cellular:
phagocytes
ingest
(neutrophils
and
digest
pathogens;
present
antigens
blood,
lymph
nodes
and
tissues
and
macrophages)
mast
cells
B-lymphocytes
(plasma
secrete
histamine
most
secrete
antibodies
blood,
tissues
lymph
nodes
and
tissues
blood,
lymph
nodes
and
tissues
cells)
T-lymphocytes
Specic
not
produce
type
to
is
defences
present
of
be
from
of
response
is
and,
that
it
or
and
are
that
known
if
effective,
are
exists
defences
because
pathogen)
We
born,
lymphocytes
that
changes
lymphocytes
highly
activated
specic
sequence
should
are
birth.
specialised
pathogen
selected,
why
coordinate
as
slower
an
responds
successful,
pathogen
invade
to
a
will
slower
with
The
to
the
and
us
in
to
to
an
every
act.
It
the
an
in
are
of
every
need
response.
This
The
specialised
adaptive
environment
survive
cells
to
involved
defences.
is
infected
They
strain
effective
increase
the
kill
potential
lymphocytes
response .
change
help
pathogens;
non-specic
select
immune
to
much
produce
than
to
to
antibodies
exist.
divide
occurs
but
however
,
and
will
response
our
(entry
of
a
environment
Figure 2.1.2
Vaccines provide protection
from infectious diseases by stimulating
again.
immune responses by the body’s specic
defence system
Summary q uestions
1
Outline
of
2
Explain
and
3
how
the
body
defends
itself
against
the
entry
5
pathogens.
the
Dene
the
antibiotic,
as
difference
cellular
Explain
defences
terms
between
against
mechanical,
parasite, pathogen,
vaccine,
chemical
6
disease.
Explain
has
antigen,
antibody,
immune response
7
why
Make
a
table
defence
to
compare
the
non-specic
Find
and
and
specic
why
the
incidence
decreased
out
defence
of
signicantly
which
neglected
concerned
4
the
system
is
described
adaptive
many
over
diseases WHO
diseases
about
and
infectious
the
past
identies
explain
why
100
as
diseases
years.
emerging
we
should
be
them.
specic
systems.
143
2.2
Non-specic
Learning outcomes
defences
Mast
cells
Pathogens
On
completion
of
this
section,
be
able
skin
describe
the function
phagocytes
defence

outline
in
of
non-specic
against
local
disease
the function
complement
describe
a
enter
break
happens,
respond
to
target
cells.
in
the
the
to
may
body
at
mucous
promote
presence
that
The
complement
of
it
the
hormone
attach

or
of
does
site,
for
lining
example
the
a
airways.
cut
in
When
receptors
on
local
travel
of
and
a
reaction
in
bacteria
is
by
mast
releasing
the
antibodies
mast
by
blood,
aided
that
but
by
cells.
These
histamine,
diffuses
the
combine
action
with
cells
which
to
is
a
adjacent
of
bacteria
and
cells.
proteins
the function
and
localised
pathogen
not
detection
proteins
a
of
mast
alcohol
cells
a
membrane
to:
this

usually
histamine
you
the
should
and
histamine
in
direct
injury
during
wounding
nonmast
cell
endothelial
specic
defences.
receptor for
activated
complement
cells
protein, C3
of
capillary
Did you know?
The
interleukins
chemical
in
1
the
is
signals
immune
released
stimulate
by
the
are
a
group
released
system.
of
by
cells
Interleukin
macrophages
brain,
to
causing fever
histamine
infection
by
bacteria
activates
complement
protein, C3
neutrophil
and
sleepiness.
Fever
is
one
of
neutrophil
non-specic
attracted
to
bacteria
by
blood
through
defences.
complement
Figure 2.2.1
1.
leaving
our
Chemotaxis
and
chemicals
released
by
bacteria
leaky
capillary
wall
When stimulated, mast cells release histamine by exocytosis to influence
surrounding target cells including the endothelial cells that line capillaries
bacterium
Histamine
stimulates
inflammation .
As
a
part
range
of
of
this,
non-specic
neutrophils
defences
are
known
attracted
from
as
the
blood
to
complement
proteins
and
chemical
the
infected
area
and
tissue
phagocytes
are
activated.
products
neutrophil
of
2.
3.
Adherence
bacterium
Fusion
A
variety
of
changes

capillaries

white
occurs
become
when
a
tissue
becomes
inamed:
leaky
lysosome
and

plasma

the
cells,
the
such
as
neutrophils
and
monocytes,
leave
the
blood
tissues
proteins,
area
from
phagosome
nucleus
blood
enter
such
becomes
hot
as
complement
and
red
and
the
and
antibodies,
tissues
swell
leave
with
the
uid
blood
derived
plasma
forming

4.
tissue
phagocytes
(macrophages)
are
activated
to
become
more
Killing
aggressive
in
engulng
bacteria.
phagosome
lysosomes
lytic
into
5.
release
enzymes
Phagocytes
phagosome
Neutrophils,
macrophages
other
particles
foreign
by
and
other
phagocytes
engulf
pathogens
and
endocytosis.
Digestion
Numbers
Breakdown
debris
of
out
of
of
the
capillary
neutrophils
bone
walls
marrow,
into
increase
circulate
tissues.
They
rapidly
in
do
the
not
during
blood
live
an
and
for
infection
then
long
as
leave
after
they
pour
through
engulng
and
bacterium
digesting
replace
Figure 2.2.2
bacteria.
those
that
More
die.
are
produced
During
a
lung
and
released
infection
from
they
capillaries
144
leave
marrow
the
bacteria.
and
See
digest
page
their
176
for
way
the
through
the
consequences
lining
of
of
this.
alveoli
to
to
alveolar
A phagocyte engulfs
bacteria and uses enzymes in lysosomes to
digest them
will
bone
reach
Module
Antigen
Tissue
presentation
phagocytes
that
are
do
macrophages.
not
Applications
S tudy
These
are
larger
,
longer
always
digest
bacteria
fully.
Instead
from
the
transmembrane
specic
them
proteins
immune
proteins.
in
outside
and
system.
same
the
bacterium,
‘present’
These
B -lymphocytes
the
of
also
these
proteins
engulf
are
some
insert
these
antigens
known
to
as
antigens
they
stands for
major
take
complex. There
into
cells
MHC
and
biology
foc us
histocompatibility
molecules
of
lived
MHC
phagocytes
3
of
are
the
class
similarly
two
class
II
present
in
I
classes
and
class
presentation
different
proteins.
of
these
these
II.
of
on
are
antigens
cells. There
proteins
proteins
Both
is
but
more
page
–
involved
on
about
147
.
Complement
Did you know?
Phagocytes,
proteins
in
such
the
as
neutrophils,
bloodstream
are
do
not
function
stimulated
by
alone.
Complement
pathogens
and
by
Complement
antibodies
and
act
in
a
cascade
fashion
to
stimulate
a
range
of
The
responses
proteins.
including
There
neutrophils
is
a
engulf
phagocytosis.
complex
bacteria
There
sequence
or
attack
are
of
about
changes
them
20–25
that
directly.
of
system
C3,
plays
a
central
role.
Bacterial
and
fungal
to
because
of
the
complement
system
that
activate
to
rid
get
antibodies
cascade.
At
the
non-specic
end
activate
of
defences
each
as
a
different
cascade,
shown
in
set
C3
of
enzymes
protein
Figure
is
enzymes
in
attached
to
helps
so
antibodies
can
of
bacteria. We
act
in
a
without
now
know
activation
by
Bacteria
are
removed
a
the
body
much faster
when
separate
activated
to
stimulate
complement
work
2.2.3.
on
antibodies
it
activate
from
cascade;
name.
was
help
compounds
other
strange
complement
antibodies.
enzymes
a
proteins
called
they
protein,
of
these
occur
The
is
defence
proteins
together
their
and
compared
antibodies
with
either
own.
bacterial
bacteria
cell
walls
enzyme
cascades
Summary q uestions
1
Outline
the
role
of
a
mast
cells,
C3
and
stimulates
and
bacterial
cell
cells
to
complement
proteins
mast
in
antibodies
b
defence
against
bacterial
release
pathogens.
walls
stimulate
activation
complement
of
histamine
protein C3
2
attracts
Distinguish
and
between
neutrophils
macrophages.
Active
inflammation
neutrophils
C3
3
from
Copy
the
diagrams
phagocytosis
digestion
makes
attaches
to
forms
membrane
large
capillaries
receptors
on
attack
in
sheet
and
intracellular
Figure
of
2.2.2
on
a
paper. Annotate
complex
more
phagocytes
of
blood
with
the
permeable
diagram
to
explain
what
other
happens
at
each
stage.
complement
4
proteins
phagocytes
State
by
and
the
bonds
proteases
and
are
broken
nucleases
that
destroy
are found
bacteria
Figure 2.2.3
lysis
of
in
lysosomes.
bacteria
5
The central role of the complement protein, C3, in defence against
a
pathogens
Outline
what
happens
during
inammation.
b
Non-specific defences
Suggest
might
against viruses
how
infection
of
host
cells
by
dengue
viruses
stimulates
the
production
chemicals
including
interferon,
which
is
a
to
an
as
infection
1
a
(see
of
pages
hormone-like
interleukin
stimulate fever
response
The
that
engulf
100–101 for
some
non-specic
ideas).
defence
against
infections.
inuenza,
It
such
production
infected
is
of
with
viral
infections.
mainly
as
It
is
responsible
muscle
antibodies
and
and
joint
the
also
for
produced
the
pain.
during
symptoms
Interferon
T-lymphocytes
of
also
that
inuenza
dengue
fever
activates
destroy
cells
and
the
6
Describe
the
action
macrophages
in
of
antigen
presentation.
DENV
.
145
2.3
Lymphocytes
The
Learning outcomes
immune
groups
On
completion
should
be
able
of
this
section,
of
describe
the
origin
of
and
groups
form
the
differences
between
and T-cells
identify
the
genes
different
types
are
of
T-cell
a
outline
lymphocytes
the
term
B -cells
type
for
difference
humoral
and
immune
responses.
between
of
to
the
B -cell
in
potential
its
that
surface
amongst
regions
has
a
specicity.
cell-mediated
(TCR)
that
structure
to
BCRs.
variation
in
BCRs
molecules
cholera
bone
T-lymphocytes.
marrow.
T-cells.
Both
involves
receptors.
these
of
the
cells.
the
Stem
groups
cells
of
divide
cells
This
Similarly,
shaped
each
gives
B -cells
antibody
differently
rearrangement
rise
have
B -cell
type
of
to
that
receptor
T-cell
a
of
go
has
that
they
secrete.
(BCR)
a
the
huge
receptors
molecules
on
the
such
and
as
identies
Also,
and
TCRs
surface
the
its
T-cells
of
specicity.
do
not
allows
released
have
to
that
T-cell
different
bacteria
This
recognise
microorganisms
by
a
antibodies.
lymphocytes
invading
toxins
TCRs
secrete
that
and
their
cause
huge
the
cell
tetanus,
diphtheria.
thymus
S tudy
gland
foc us
B-lymphocytes
usually
main
immune response
products,
are
two
lymphocytes
originate
and
process
cell
variation
identical
receptor
the
code
of
identies

of
maturation
that
amount
Each
dene
and
are
and T-cells)
explain

B -lymphocytes
maturation of
potential
through

as
There
lymphocytes
to
B-cells
known
lymphocytes.
and
Both

lymphocytes
the
to:
maturation
(B-cells
involves
you
Origin

response
and T-lymphocytes
abbreviated
and T-cells. To
save
to
space
B-cells
that
is
mature
what
we
will
call
them
here.
immature
T-lymphocytes
Immunology
has
many
long
words
T-lymphocytes
and
many
abbreviations.
It
might
be
lymphoid tissue,
marrow
a
good
idea
glossary
you
of
read
to
make
these
your
own
e.g.
abbreviations
lymph
on.
mature
mature
Did you know?
to
genetic
10
rearrangement
million
antibodies
different
and
lymphocytes.
cell
It
is
leads
variants
receptors
thought
and
have
TCRs
and
enough
BCRs
to
in
recognise
blood
these
Origin and maturation of lymphocytes
their
any
type
B -cells
of
in
lymph
on
that
variation
and
of
Figure 2.3.1
cells
B-
T-lymphocytes
B-lymphocytes
circulate
The
nodes
as
are
produced
constantly
in
the
bone
marrow;
they
mature
and
antigen.
then
leave
the
throughout
bone
bone
the
marrow,
marrow
body.
but
all
in
T-cells
go
the
are
into
blood
to
produced
the
thymus
occupy
early
gland
in
in
lymphoid
life
the
and
tissue
also
chest.
leave
This
the
organ
Did you know?
doubles
Sometimes
lymphocytes
do
attack
T-cells
B-
the
body’s
own
cells.
Diseases
and
cause
are
auto-immune
have
another
category
our
of
list
afnity
populate
involves
the
and
puberty
lymphoid
death
of
and
tissue.
cells
that
then
The
have
shrinks
after
maturation
cell
all
the
process
receptors
with
are
for
‘self ’
killed
antigens.
because
of
The
this.
majority
These
of
cells
include
all
that
those
mature
that
of
a
in
the
recognise
disease
on
page
antigens.
This
is
to
ensure
129.
destroy
146
to
birth
diseases
‘self ’
missing from
between
left
T-cells
thymus
–
size
with
high
this
in
the
body ’s
own
cells.
that
the
immune
system
does
not
Module
As
as
lymphocytes
CD
proteins
identify
mature,
(CD
different
immature
they
stands
classes
lymphocytes
of
do
Lymphocyte
CD
B-lymphocytes
CD20
helper
develop
for
other
cluster
of
lymphocytes
not
develop
receptors
cell
surface
receptors
differentiation).
as
you
CD
can
see
receptors
CD
in
Applications
of
biology
known
receptors
the
then
3
table.
they
are
If
killed.
Function
CD4
T-lymphocytes

present

differentiate
antigens

respond

secrete
to
to
into
helper T-cells
plasma
antigens
cytokines
cells
that
presented
to
by
stimulate
secrete
cells
B-cells,
antibodies
with
MHC
class
II
cytotoxic T-cells
proteins
and
non-specic
defences
cytotoxic
CD8
T-lymphocytes
regulatory
CD4
and CD8
T-lymphocytes
CD4
and
receptors
cells.
CD8
receptors
(BCRs
and
Lymphocytes
spleen
and
liver
.
help
TCRs)
circulate
In
so
to
and
respond

attack
cells

attack
cancer

regulate

suppress
stabilise
the
they
the
MHC
between
doing,

antigens
the
cells
with
and
specic
by
cells
intracellular
transplanted
defence
with
MHC
class
I
proteins
parasites
tissues
system
auto-immunity
interaction
on
lymph,
into
presented
infected
proteins
blood,
come
to
between
lymph
contact
the
cell
antigen-presenting
with
nodes,
any
the
pathogens,
Did you know?
toxins,
other
antigens.
foreign
Note
that
material
and
phagocytes
T-lymphocytes
that
differentiate
might
into
be
these
processing
different
classes
Humoral
before
taking
part
in
an
immune
response;
they
do
not
differentiate
about
the
different
classes
during
or
after
an
immune
is
strange
word
to
use
something
so
serious
and
response.
potentially
from
Immune
a
into
responses
the
life-threatening.
use
mediaeval
of
the
term
medicine
to
It
comes
humour
refer
to
in
body
uids.
The
specic
responses.
These
presentation
rst
and
time
The
of
that
group
of
involve
is
the
characterised
selection
When
are
complementary
of
a
small
clone,
clones
that
as
of
to
the
have
all
having
of
of
enters
the
lymphocytes
antigens
express
receptors
immune
lymphocytes
pathogen
numbers
they
by
groups
particular
only
is
very
a
are
cells
activation
system
antigens.
there
TCRs
small
defence
of
the
the
by
the
body
with
pathogen.
same
BCR
complementary
to
for
Summary q uestions
BCRs
or
Each
1
TCR.
is
clonal
selection .
In
order
to
be
effective,
many
the
maturation
more
to
be
produced.
In
clonal
expansion
the
activated
Describe
by
humoral
immune
response
involves
the
production
of
antibodies
B -cells.
Helper
against
pathogens
T-cells
may
while
also
they
be
are
involved.
in
the
Antibodies
blood,
lymph
are
and
very
what
happens
tissues.
B-cells
pathogens
Name
They
are
of
limited
use
in
protecting
against
the
different
describe
as,
being
cell-mediated
protein,
they
cannot
cross
cell
immune
response
does
not
It
involves
cytotoxic
T-cells
that
are
Outline
intracellular
parasites.
These
the functions
presence
involve
B -cells
within
the
DENV
cell
This
is
host
cells
proteins
surface
antigen
cytotoxic
cells.
as
when
For
some
of
their
attach
Golgi
example,
the
most
pathogens
antigens
to
presentation .
T-cells
with
the
MHC
vesicles
The
during
class
fuse
antigen
appropriate
I
is
the
and
Outline
the following
appear
cell
and
in
to
in
give
the
the
are
surface
detected
by
stages
important
tend
processing
proteins
with
B-cell
and
immune
responses:
antigen
away
clonal
selection
cell
and
of
of
receptors
proteins.
presentation,
membranes
of T-cell
membranes.
of
against
types
their functions.
cells
5
antibodies.
body
as
intracellular
MHC
their
and T-cells
mature.
receptors, T-cell
defence
to
effective
between
4
The
and T-cells.
by
and
within
B-cells
and
mitosis.
3
The
origin
lymphocytes
they
divide
of
of
cells
potential
need
sites
the
2
antigens
State
clonal
expansion.
Golgi
exposed
at
membrane.
patrolling
6
Distinguish
immune
between
response
mediated
the
and
immune
humoral
the
cell-
response.
TCR.
147
2.4
The
immune
response
Both
Learning outcomes
humoral
different
On
completion
should

be
able
outline
and
of
this
section,
of
cell-mediated
immune
responses
occur
in
two
slightly
ways.
Humoral
stages
cell-mediated
you
to:
the
and
immune
response
humoral
The
humoral
The
diagram
response
involves
the
production
of
antibodies
by
B -cells.
immune
shows
the
events
that
happen
during
a
humoral
immune
responses
response.

describe
antigen
what
happens
presentation,
selection,
clonal
during
directly
clonal
expansion
are
to
many
describe
destroy
how
of
cytotoxic T-cells
outline
in
infected
the
role
long-term
host
respond
B -cells.
cells
of
memory
B -cells
immunity.
the
are
skin. These
by
phagocytic
are
dengue
the rst
are
the
the
diagram
involvement
require
to
large
the
interact
multiple
these
because
of
B -cells
helper
can
T-cells,
respond
but
there
T-cells.
molecules
large
with
a
with
polysaccharide
many
interaction
differentiate
also
to
cells
be
viruses. They
are
respond
interact
the
Helper
infected
directly
these
These
This
processed
Did you know?
cells
like
and
within
in
that
to
repeated
into
is
BCR
receptors
sufcient
plasma
molecules
structure.
to
on
on
the
activate
the
surface
surface
the
B -cell
of
to
cells.
cells
each
Langerhans
parts
without
responses
bacteria.
divide

antigens
two
secretion
Antigens

are
and
B -cells
antibody
There
B -cell.
with
BCRs
into
T-cells
They
are
with
CD4
antigen
small
antigens,
BCR
taken
MHC
class
TCRs
secrete
differentiate.
protein,
to
single
into
II
the
cell
proteins
proteins
that
by
and
the
protein
this
molecules
happens,
endocytosis.
presented
to
activate
stabilise
as
When
complementary
cytokines
and
such
receptors.
the
the
They
on
the
antigen
B -cell
interaction
to
antigens
are
cell
bind
divide
between
that
the
surface.
to
the
and
MHC
TCR.
important APCs.
The
cells
activated
within
cells.
ribosomes
Link
reticulum.
Find
an
plasma
electron
cell. There
Module
how
micrograph
1
the
in Unit
cell
synthesis
is
and
one
Look
in
4. Your
help
revise
2.2
answer
in
of
at
protein
aspects
and
Golgi
cells
in
Most
an
of
the
the
of
genes
to
packaged
clone
do
not
antibodies
are
the
of
large
both
B -cells
membrane
assembled
bodies,
each
antigen
clones
Antibody
polypeptides
Summary
annotations
many
a
carefully
adapted for
then
question
you
is
1.
of
the
Some
B -cells
form
necessary
are
antibody
vesicles
become
produced
molecules
to
transcribed,
make
into
and
in
make
on
to
the
page
as
rst
form
many
endoplasmic
They
by
remain
to
make
translated
exported
but
divide
that
rough
mRNA
response
IgM
cells
molecules.
and
active,
(see
T-cells
plasma
and
are
processed
exocytosis.
memory
Other
cells
presentation
of
150).
will
of
cell
bacterial
pathogen
with
non-repeating
B-cell
and
molecular
polysaccharide
biology.
in
its
wall
antigen
B-cell
repeated
receptor
antigen
CD4
B-cell
B-cell
B-cell
differentiating
into
plasma
receptor
B-cell
cells
receptor
and
in
helper T-cell
antigen;
processes
and
takes
antigen
presents
it
in
mitosis
MHC
activated
class
II
proteins
B-cell
MHC
activated
class
II T-cell
receptor
plasma
cell
B-cell
plasma
secretion
cell
of
secretion
antibodies
Figure 2.4.1
148
of
antibodies
The stages of the humoral immune response
Module
Cell-mediated
Many
pathogens
immune
invade
cells,
response
response
host
proteins
specic
and
so
escaping
antibodies.
cytotoxic
cells
are
In
the
the
protection
provided
cell-mediated
activated
to
attack
ingested
by
phagocytes
and
are
partly
are
presented
in
MHC
class
II
proteins.
and
kill
digested.
Helper
seems
a
complementary
proteins
again
to
help
the
to
antigen
stabilise
bind
the
to
the
pathogens
that
This
act
T-cells
the
helper
to
be
T-cells
more
to
secrete
effective
at
cytokines
killing
the
that
of
clone
these
of
helper
cells
to
T-cells
increase
also
their
divides
by
effect
so
on
body.
MHC
to
what
need
a
is
going
on
‘failsafe’
complex.
to
identify
them
correctly
interaction
activate
pathogens
mitosis
stimulatory
the
way for T-cells
monitor
they
that
would
destroy
the
within
healthy
there
cells
or
ignore
them.
parasitised
The
a
cells. They
perfectly
macrophages
as
with
otherwise
stimulates
against
enter
Their
MHC–antigen
binding.
complicated
infected
method
CD4
very
defence
inside
TCRs
foc us
system for
continually
antigens
biology
by
proteins
are
of
immune
cells.
Pathogens
Applications
S tudy
This
complement
3
are
cells.
more
macrophages.
Did you know?
Cytotoxic
T-cells
expressing
patrol
foreign
the
antigens
body.
in
When
their
they
MCH
come
class
I
across
an
proteins,
infected
they
cell
may
Some
become
active.
This
only
happens
if
the
TCR
is
complementary
to
lymphocytes
antigenic
antigen.
CD8
proteins
help
to
stabilise
the
interaction
between
MHC
material
protein,
antigen
and
TCR.
Once
activated
by
binding,
cytotoxic
T-cells
the
surface
in
the
cell
of
the
infected
cells
and
secrete
perforins
that
‘punch’
so
that
toxins
such
as
hydrogen
peroxide
dust
can
host
remove
cells
die.
This
replicating
seems
pathogens,
a
drastic
such
as
measure
DENV
or
but
the
it
is
the
only
inuenza
Examples
are
pollen
mites. Asthma
is
a
grains
disease
is
caused
by
unnecessary
enter
.
immune
The
to
perfectly
holes
that
membranes
is
x
and
to
that
class
harmless.
I
respond
the
way
responses
to
such
harmless
to
materials.
virus.
problem
It
in
is
a
growing
health
the Caribbean.
macrophage
infected
by
bacteria
Summary q uestions
infected
MHC
class
body
cell
1
Outline
the
roles
of
the following
cytotoxic T-cell
II
CD4
terms
TCR
TCR
in
immune
responses:
macrophages, B-cells, helper
T-cells, cytotoxic T-cells
cytokine
2
Outline
the
two
ways
in
which
activates
B-cells
mitosis
macrophage
helper
to
T-cell
class
immune
I
3
bacteria
Outline
activated
cell
T-cell
the
circulates
blood
in
during
other
cell-mediated
in
infected
Suggest the
advantages
The stages of the cell-mediated immune response
responses
memory
5
body
Explain
as
by
one
of
the
strains
of
the
dengue
fever
virus
tends
to
why
during
the
rst
to
reinfection
infection
not
only
by
are
the
same
plasma
strain.
cells
and
This
is
T-cells
produced,
but
also
memory
cells.
active
These
helper
cells
do
but
continue
to
circulate
in
the
blood
and
lymph
subsequent
infection.
If
they
contact
the
same
antigens,
some
respond
presentation.
Make
until
there
then
they
a
a
labelled
plasma
cell
diagram
as
seen
is
a
transmission
electron
will
micrograph. Annotate
divide
and
differentiate
into
active
B
cells
(plasma
cells)
and
active
yet
more
memory
cells.
‘Memory ’
is
not
a
very
good
name
for
them
with
have
now
a
rst
not
much
infection,
infections.
‘learnt’
larger
they
Y
ou
can
anything.
clone
can
see
of
respond
the
They
cells.
As
are
much
effect
of
just
there
are
faster
this
in
the
representatives
more
on
of
them
second
Figure
2.5.3
and
on
than
of
what
before
subsequent
page
the functions
of
the
as
structures
they
your
T-cells
diagram
and
B-cells
during
and
in
a
only
pathogens.
not
of
differentiate,
means of defending
because
6
cytotoxic
immune
give
antigen
immunity
a
against
and T-cells
long-term
and
cells
the
Infection
which T-cells
responses.
disadvantages of
Immunological
in
search
4
of
ways
cytotoxic
immune
Figure 2.4.2
humoral
responses.
the
respond
memory
during
CD8
MHC
kill
respond
you
have
labelled.
is
the
7
Explain
what
is
meant
by
immunological memory
151.
149
2.5
Antibodies
Antibodies
Learning outcomes
short).
On
completion
should
be
able
of
this
section,
you
Unit
levels
to:
It
1.
describe
the
structure
of
of
helps
molecule
explain
how
antibodies
particular
describe
how
the
antibodies
body
and
knowledge
of
polypeptides,
secondary
structure
as
and
they
protein
which
for
structure
each
tertiary
are
(Ig
have
structure.
formed
from
from
three
All
four
The
simplest
form
of
antibody
molecule
(Ig
or
class
is
composed
of
four
polypeptides
as
you
can
see
in
Figure
G
2.5.1.
IgG
molecule
act
and
two
is
composed
identical
short
of
two
identical
long
polypeptides
(or
polypeptides.
to
region
of
the
antibody
molecule
is
the
region
that
binds
to
antigens
against
–
pathogens
primary,
quaternary
immunoglobulins
are
One
defend
your
from
as
antigens
chains)

have
recall
formed
organisation:
polypeptides.
IgG)
Each
specic for
to
are
known
(IgG)
or

here
proteins
an
more
antibody
plasma
Proteins
antibodies

are
their
the
antigen-binding
site.
If
you
imagine
an
IgG
the
top
molecule
as
Y-shaped,
toxins.
these
In
a
binding
order
to
different
sites
bind
to
are
its
at
the
two
specic
antigen-binding
ends
at
antigen,
site.
This
each
is
type
possible
of
of
the
Y
.
antibody
because
molecule
amino
acids
has
can
Link
be
This
is
a
good
opportunity
to
revise
arranged
shapes.
variable
protein
structure. To
explain
how
of
antibodies
is
related
knowledge
protein
of
you
the four
structure.
Module
1
in Unit
S tudy
need
See
to
you
can
molecules
to
The
of
1.8
of
see
in
really
since
to
2.5.
1,
IgG
shaped
polypeptides
do
our
efcient
as
in
‘sticks’
highly
in
the
antigen
to
similar
a
give
vary,
to
different
these
the
receptor
binding
contact
with
of
with
The
the
polypeptides
molecule
site
regions
bodies.
three-dimensional
regions
active
sites
are
of
also
called
enzymes,
sites,
in
that
they
have
and
a
specic
agent.
are
‘t
better
joined
by
that
it
molecule
binds.
around’
the
to
exibility
antigens
antibody
which
to
response
some
an
‘t’
We
the
is
need
many
different
between
complementary
antibodies
antigens
antigen
and
that
in
with
may
antibody,
the
infection.
disulphide
so
may
that
be
the
bonds,
two
separated
but
binding
by
the
hinge
sites
slightly
can
region
gives
make
different
distances.
like
constant
region
is
the
same
for
all
antibodies
of
the
same
class.
The
not
polypeptides
regions
of
IgG
molecules
are
all
identical,
whatever
the
are
specicities
shown
antigen
variable
more
constant
branch. The four
the
enter
The
a Y,
are
neurotransmitter
antigen-binding
shape
The
Figure
not
and
complementary
different
1.
foc us
are
They
to
sites
to
the
As
sequences
binding
use
levels
1.6
these
the
shape
their function,
different
regions .
hormone
structure
in
Because
of
the
variable
regions.
These
constant
regions
bind
to
diagrammatic form
receptors,
for
example
There
four
those
on
the
surfaces
of
phagocytes.
diagram.
binding
sites
are
different
Class of
Number of
antibody
binding
IgA
2
or
4
classes
antigen
of
antibody
as
shown
in
the
table.
Functions
sites

inhibits

prevents
adherence of
bacteria to
host
cells
hinge
region
variable
mucous
bacteria forming
membranes,
e.g.
colonies
in
the
on
gut
region
IgE
2

constant
secrete
region
activates
histamine
–
mast-cells
during
to
infections,
light
but
polypeptide
also
during
unnecessary
responses
to
disulphide
chain
harmless
bond
pollen
objects
(allergic
such
as
dust
mites
and
reactions)
heavy
polypeptide
constant
chain
IgG
receptor
binding
molecule

activates

helps
complement

neutralises

causes

activates

causes
macrophages
proteins
engulf
pathogens
toxins
agglutination
of
bacteria
site
IgM
Figure 2.5.1
150
2
region
10
complement
proteins
The structure of an antibody
agglutination
of
bacteria
Module
Antibodies

full
a
Agglutination
antibodies
bigger

wide
of
for
Immobilisation
types

of
contact
Neutralisation
have
very
diphtheria
of
of
toxin
viruses
on
to
and
biology
two
or
hold
more
them
bacteria
together
to
make
the
toxins:
into
cells:
of
cells
the
agella
are
from
prevent
host
and
bacteria
Examples
choleragen
to
Antibodies
bacteria
surface
Some
bind
of
some
moving.
and
entering
effects.
and
them
pathogens
of
DENV
,
severe
binding
Antibodies
prevent
entry
as
By
of
roles.
spreading
bacteria:
to
proteins
such
of
Applications
phagocytes.
proteins
with
viruses,

of
surface
them
of
bacteria
Prevention
the
bacteria:
prevent
targets
number
3
cells.
being
release
This
bind
to
making
prevents
replicated.
toxins,
botulinum
cholera
that
them
which
toxin,
bacteria.
often
tetanus
toxin,
Antibodies
that
Figure 2.5.2
This computer model shows
an antibody attached to an antigen
forming an antigen–antibody complex
form

complexes
Breaking
has
a
bacteria:
break
lower
open
water
and
the
help
to
are
them
walls.
body
that
The
uids,
are
antitoxins
combine
cytoplasm
so
water
with
of
other
bacteria
enters
by
burst.
facilitate
‘mark’
harmless
antibodies
cell
than
cells
them
phagocytosis:
for
destruction
Antibodies
by
that
phagocytes.
attach
This
to
is
opsonisation
Activating
systems
Antibody
that
protein:
activates
Some
antibodies
complement
concentrations
in the
activate
protein,
C3
one
(see
of
the
page
145).
concentration
measured.
in
During
the
the
blood
primary
of
any
one
immune
antigen
0)
second
to
(Day
antibody
presentation
expansion
the
of
antigen.
have
appropriate
then
decreases
When
a
to
response.
the
to
This
place
is
specic
antibody
response
clone
it
plasma
clonal
are
molecules
of
the
takes
can
a
5
10
are
differentiate
removed
antigen
in
the
many
into
and
cells
increases
identical
there
selection
to
a
for
the
clonal
plasma
to
the
secondary
cells
Antibody concentration
responses
secrete
and
Summary q uestions
of
antibody
1
Make
of
immune
an
a
simple
Annotate
the
describe
cells.
is
the
presence
response
that
molecules.
secreted
will
by
memory
also
plasma
and
antigen.
of
responsible
Notice
become
second
is
that
cells.
established
any
and
by
the
there
This
subsequent
Antibodies
cells
for
the
is
a
means
that
a
by
faster
greater
that
it
person
infections
produced
beginning
much
by
other
of
the
is
has
the
as
unlikely
no
clones
of
of
that
with
B-cells
antibody
more
that
2
molecules
any
symptoms
pathogen
are
pathogen
different
will
strain
of
also
the
show
same
the
same
pathogen
pattern.
will
But
produce
a
an
your
diagram
the function
of
to
each
part.
infection
during
that
why
the
infection
different
by
the
shown
specic
responded
Describe
the four
organisation
of
a
levels
Figure
of
protein.
antibody
in
these
of
Explain
molecule
2.5.
1
has
all four
levels.
to
3
that
diagram
molecule.
secondary
production
response
labelled
antibody
labelled
It
35
circulation.
occurs,
more
30
during primary and secondary immune
maximum
from
25
20
time/days
the
able
15
be
while
following
plasma
are
immediately
because
to
the
there
20)
blood
concentration
almost
happens
in
because
before
The
presentation
B -cell
appear
antibody
increases
This
appropriate
take
antibody.
as
second
concentration
molecules
exposure
antigen
response
Figure 2.5.3
specic
the
primary
0
The
response
exposure
the
(Day
ytitnauq
cascade
complement
to
fo

secondary
initial
ydobitna
bacteria
to
Lysins
potential
pathogens
make
bacterial
bacterial
Coating
to
eht ni
osmosis

open
to
toxins
doolb
proteins
with
Explain
how
the
structure
of
a
an
response.
antibody
is
related
to
its
function.
HIV
4
and T-cells
Explain what is meant by the term
specicity as applied to antibodies.
HIV
infects
protein.
binds
to
helper
they
the
often
the
few
fact
as
burst
HIV+
T-cell
cell
the
CD4
T-cells
treating
at
In
a
types,
glycoprotein
protein
to
described
open.
in
the
entry
page
the
as
As
the
T-cells
gp120)
into
132.
decreases
monitor
helper
(known
gain
on
This
patients
count
including
the
the
progress
of
on
cell.
host
number
expressing
HIV
cells
of
the
the
the
surface
infects
infection
of
HIV
the
produce
T-cells.
CD4
viruses,
Doctors
by
looking
5
Figure
2.5.3
secondary
Explain
shows
immune
the
in
the
of
and
responses.
changes
concentration
shown
primary
in
the
antibody
as
graph.
blood.
151
2.6
Types
of
immunity
So
Learning outcomes
far
body.
On
completion
should
be
able
of
this
section,
we
This
response
you
Natural
to:
active

explain
the
difference
have
is
considered
active
and
the
active
what
immunity ,
protection
immunity
immunity
happens
which
always
an
term,
often
happens
when
you
when
you
are
antigen
involves
long
happens
is
when
an
lasting
are
given
a
enters
a
the
immune
lifetime.
infected.
vaccine
Articial
that
contains
an
between
antigen.
active
and
passive
immunity
It

explain
the
difference
is
also
This
natural
and
artificial
is
state
examples
of
passive
the four
and

immunity
explain
in
the
how
cross
vaccination
control
of
is
passive
infectious
give
the
importance
by
existing
and
immune
Here
the
by
simply
body
receiving
gains
antibodies.
antibodies
into
contact
with
the
antigen.
from
No
another
immune
its
mother
.
or
instant
passive
during
Breast
occurs
are
milk
when
immunity.
diphtheria
immunity
pregnancy;
is
also
rich
given
who
occurs
occurs
in
antibodies
People
often
it
IgA
are
are
injected
by
antibodies
a
child
antibodies.
likely
antitoxin
when
when
to
into
have
injection
is
Articial
a
person
to
tetanus,
as
a
of
In
each
case,
the
antitoxin
neutralises
the
toxins
released
vaccination
by
programmes
come
Natural
immunity
precaution.
maintaining
not
placenta
them
rabies
discuss
has
occurs.
the
breastfed
used
diseases

become
types
response
of
to
immunity .
immunity
source

possible
between
developing
each
of
the
pathogens
and
prevents
the
damage
that
the
toxins
can
new
cause.
ones
globally
and
in
the
This
Caribbean.
table
summarises
the
main
points
about
these
four
types
of
immunity.
Type of
natural
immunity
Example
active
a
immunity
person
is
measles,
immune
Advantages
infected
which
by
immunity
promotes
is
Disadvantages
long
term
immune
an
response
active
vaccination
immunity
against
e.g.
natural
passive
mother
(breast
passive
not
symptoms
develop;
toxin
is
to
in
immediate
across
common
colostrum
mother
milk)
against
tetanus
collected from
donations
need
long
term;
suffer from
immune
the
and
blood
protection
diseases
has
had
immunity
the
young
hospital.
that
Read
the
introduction
to
the
an
two
very
carefully
and
then
run
he
man
The
is
at
injection
also
graphs
be fatal
not
immediate
protection
destroyed
no
to
takes
time;
immediate
and
an
is
involved
team
risk
of
of
in
of
the
a
nasty
Accident
tetanus
tetanus
injection
in
the
are
destroyed
as
he
has
antibodies
vaccine
car
and
to
for
accident
and
Emergency
got
give
soil
in
him
tetanus
in
in
his
is
produced
term;
gradually
the
cells
body;
produced
transferred
department
wounds.
immediate
case
body;
short
are
memory
gradually
the
cells
is
antibodies
diphtheria
short-term;
in
memory
immunity
disease,
tetanus
is
antibodies
been
against
e.g.
to
that
or
vaccinated
specic
injected
A
foc us
immediate;
response
protection
no
S tudy
may
time;
disease
child
and
antibodies
immunity
no
passed from
to
placenta
articial
diseases,
measles
antibodies
immunity
immunity
infectious
takes
protection
disease
articial
response
he
has
to
decides
He
is
given
protection
never
and
been
a
vaccinated.
ruler
across
right
and
two
note
types
Summary
152
each
of
graph from
the
changes
antibody.
question
1.
left
in
Now
to
the
answer
The
in
health
his
workers
blood
hospital.
so
The
take
decide
blood
results
are
to
check
samples
shown
in
that
at
he
has
regular
Figures
enough
intervals
2.6.1
and
of
the
while
2.6.2.
antibodies
he
is
in
Module
stinu
stinu
25
15
10
of
biology
20
15
10
ydobitna
ydobitna
5
Applications
25
yrartibra/noitartnecnoc
yrartibra/noitartnecnoc
20
3
5
0
0
20
time
of
Figure 2.6.1
injection
20
time/days
time
Changes in antibody concentration in the blood
Figure 2.6.2
following an injection of antibodies to protect against tetanus
V
accination
offered
by
vaccinated
were
against
responsible
Many
case
programmes
governments
of
of
these
polio
transmission
still
exists
travellers
the
of
in
for
the
from
much
ill
are
had
world
areas
used
health
very
rare
was
been
and
important
citizens.
that
Americas
polio
an
their
diseases
diseases
in
are
to
it
be
and
in
in
is
many
the
1991
be
still
of
the
and
common
health
in
are
populations
in
for
example
1994
it
interrupted.
introduced
endemic.
protection
children
and
deaths.
region;
and
successfully
could
where
to
part
Infants
Changes in antibody concentration in the blood
following an injection of a vaccine to protect against tetanus
into
In
But
the
2011
was
the
last
declared
the
Americas
there
that
disease
were
by
181
Figure 2.6.3
cases
of
polio
in
Pakistan
and
as
of
2012
the
disease
still
exists
there,
A child in the North West
in
Frontier Province of Pakistan receiving oral
neighbouring
WHO
will
follow
the
countries
one
day
and
in
announce
progress
of
the
parts
the
of
W
est
Africa.
eradication
campaign
by
of
It
this
searching
is
hoped
disease.
online
that
Y
ou
the
polio vaccine as part of the programme to
eradicate polio
can
for
‘polioeradication’.
S tudy
During
eradication
vaccination
programmes
schemes
give
rise
vaccination
to
herd
is
used
immunity
in
in
two
which
ways.
almost
all
Find
people
are
immune.
People
who
do
not
respond
to
vaccines
are
out
about
the
chances
of
them
coming
into
contact
with
the
disease
as
most
people
around
them
have
immunity
and
will
not
disease.
Surveillance
identies
people
who
have
caught
the
BCG. You
disease;
of
it
spreading
all
contacts
and
people
in
the
neighbourhood
–
this
is
ring
them. Which
had
infectious
do
they
protect
against
and
are
when
vaccinated
Hib,
probably
to
diseases
prevent
HepB,
have
transmit
many
the
DTP, OPV,
are
MMR,
small
the following
protected
vaccines:
because
foc us
Mass
should
they
be
given? Use
the
vaccination
information
Summary
you nd
question
to
help
answer
2.
Summary q uestions
1
Describe
the
two
and
explain
the
changes
in
antibody
concentration
that
occur
in
S tudy
You
2
Explain,
using
examples,
how
vaccination
is
used
in
the
control
should
infectious
using
infectious
by
examples,
why
vaccination
is
not
used
to
control
some
diseases.
4
Immunisation
5
Hospitals
is
the
should
active
or
passive. What
are
the
advantages
of
each
Extended
and CAREC
be
exam
used
countries
how
this
with
venomous
anti-venom
is
snakes
produced.
hold
supplies
of
in
your
on
information
answers
question. You
should
to
also
type?
understand
in
Programme
Immunisation. Current
any
Outline
information
PAHO, WHO
diseases.
about
Explain,
read
of
provided
3
foc us
graphs.
anti-venom.
should
be
why
up
to
you
date
and
your family
with
your
vaccinations.
153
2.7
Monoclonal
During
Learning outcomes
a
On
completion
should
be
able
of
this
antibodies
section,
range
T-cells
you
dene
the
of
different
advantage
to:
term
immune
are
others

an
at
antigens.
selected
that
response
and
some
attaching
antigen-presenting
As
antibodies
to
a
result,
activated.
and
This
many
is
a
produced
helping
to
cells
process
clones
of
polyclonal
will
destroy
be
B -cells
effective
pathogenic
present
and
response
more
the
and
with
the
than
bacteria.
monoclonal
Each
clone
of
B -cells
produces
one
type
of
antibody
with
a
highly
specic
antibody
antigen

outline
the
process
by
site.
which
In
monoclonal
binding
antibodies
the
1970s,
scientists
in
Cambridge,
UK,
developed
a
method
for
are
producing
antibodies
from
single
clones
of
B -cells.
The
main
problem
produced
that

explain
the
advantages
monoclonal
diagnosis

explain
antibodies
and
the
of
using
in
of
in
B -cell
treatment
use
they
kept
in
pregnancy
This
antigenic
monoclonal
anticancer
material,
each
Mabs for
blood
such
as A,
(Rhesus). When
cells
of
Mab
type A,
aggregate
B
and
visible
three
drops
you
of
to
anti-A
the
into
the
Mabs
red
is
of
example
isolated
cells)
immunising
red
from
blood
the
a
them
which
small
cells
animal’s
of
do
not
with
survive
survive
and
mammal
type
spleen
A.
divide
in
with
After
and
if
malignant
several
fused
form
hybridoma
cells.
These
were
kept
in
with
culture
and
was
isolated
Cells
were
that
grown
so
that
produced
in
culture
the
the
antibodies
required
where
they
secreted
antibody,
divided
and
(if
any)
anti-A
then
could
in
this
produced
is
eye.
added
in
to
to
this
the
single
many
antibody
–
monoclonal
a
monoclonal
antibodies
on
antibody
the
(Mab
market
for
are
used
in
blood
typing.
Mabs
in diagnosis
which
Each
are
many
different
Mabs
for
diagnosis
and
for
research.
Pregnancy
of
separate
results
response
types AB+
of
added
blood
clumps,
naked
blood. What
expect
blood
cell
Amongst
testing
the
myeloma
rst
B -cells
fuse
D
There
are
as
to
group
those
blood
to
quantities
short).
to
by
individual
was
foc us
large
are
for
were
cells
identied.
example,
antigens,
(known
done
that
solution
treatment.
be
There
cells
was
was
The
testing
then
S tudy
overcome
culture.
B -cells
myeloma
and
to
tumour
culture.
weeks,
antibodies
had
tissue
would
samples
of
used
diagnostic
kits
test
to
be
kits
for
done
are
the
gonadotrophin
by
doctors
available
presence
(hCG),
of
in
that
the
or
at
use
health
Mabs
to
glycoprotein
clinics.
give
Now
instant
hormone,
home
results.
human
These
chorionic
urine.
and O–?
Figure
2.7.2
positive
shows
and
Monoclonal
by
having
proteins
changes
in
the
identication
specic
for
used
the
to
are
also
testing
used
hormones
of
various
urethritis,
pregnancy
follow
number
of
a
kit
works
to
give
both
results.
antibodies
Mabs
are
how
negative
the
T-cells
is
FSH
fertility
and
progression
sexually
which
in
in
the
LH.
of
by
the
Mabs
HIV
blood.
transmitted
caused
testing
kits.
These
raised
against
infections
They
are
infections,
pathogen
also
work
by
used
such
as
Chlamydia,
CD
detecting
in
the
non-
and
gonorrhoea.
Figure 2.7.1
A home pregnancy testing
Mabs
in
cancer treatment
kit that uses monoclonal antibody raised
against the hormone, hCG
Mabs
can
which
They
be
used
express
are
deliver
not
drugs
Rituximab
is
to
target
particular
only
that
a
located
will
Mab
specic
cell
by
affect
that
is
cells
surface
Mabs,
only
used
but
the
to
in
the
antigens
also
cells
treat
body.
can
be
For
example,
located
destroyed
by
those
using
Mabs,
Mabs.
which
targeted.
certain
cancers
of
B -cells.
It
is
®
marketed
The
Mab
receptor
surface
154
under
a
locates
protein.
of
variety
of
cancerous
This
plasma
is
cells.
names
cells
found
Its
that
on
mode
including
express
the
of
MabThera
surface
action
is
the
of
not
CD20
B -cells,
cell
but
completely
surface
not
on
clear
,
the
but
Module
hCG
binds
mobile
hCG
of
in
the
urine:
urine for
5
the
pad
particles
First
zone: The
bind
to
a
the first
mobile
Mabs
layer of fixed
window
Figure 2.7.2
should
seconds. When
that
start
have
that
hCG
Mabs
pad
in
a
up
move
test
stream
first
second
zone
zone
antibody-latex
a
with
blue
Second
hCG
cross
to
in
a
shows
present.
zone: Antibodies
second
that
up
the
no
cross
antibodies
sampler. This
in
that
layer of fixed
the first
is
have
have
been
important
window,
a
binding
that
lead
some
severity
own
to
the
to
the
of
tissues,
target
B -cells.
CD20
death
protein,
of
the
rituximab
cell.
these
of
sequences
diseases,
antibodies
is
of
‘self ’
are
to
the
primary
amino
the
causes
Rituximab
in
have
that
result
is
if
bind
here
moved
there
is
correct.
a
variety
is
has
also
secreted
as
which
the
multiple
of
B -cells
been
immune
sclerosis
appears
system
by
the
embryo
of
after fertilisation.
Later
it
is
used
by
the
placenta.
See
and
to
reduce
attacks
our
Module
Unit
3
Section
2.4
in
the
guide for
1.
antigens.
on
in
cells,
that
diagnosis
such
specicity
structure
acids
such
numbers
effective
antigens
due
the
diseases,
Reducing
expressing
specic
This
function
and
indicate
hCG
line
Link
auto -immune
arthritis.
Monoclonal
can
coloured
Pregnancy testing using monoclonal antibodies. If there are two coloured
rheumatoid
the
bound to
mobilised
to
negative
secreted
treat
not
antibodies. A
shortly
to
biology
sampler
hCG
changes
of
urine
pad
lines then the result is positive.
following
Applications
move.
gives
is
absorbent
held
the
combined
antibodies. This
indicating
be
wet,
to
to
Mab
3
of
of
as
the
their
variable
antibodies
exist
within
and
treatment
CD20
and
these
as
proteins
regions,
the
they
on
which
is
a
different
regions.
Summary q uestions
1
Dene
2
Explain
why
3
Explain
how
4
Make
table
the
term
monoclonal antibody
Mabs
are
Mabs
are
produced
used
in
by
a
(Mab).
process
pregnancy
that
testing
involves
cell fusion.
kits.
Figure 2.7.3
a
the following
5
Outline
6
Explain
7
Use
the
the
your
using
to
show
Mabs:
advantages
should
results
anti-A,
reasons for
knowledge
Mabs
the
of
be
anti-B
using
of
testing
and
Mabs
using
the
of
in
Mabs
menstrual
blood
anti-D
(D
treating
in
of
is
to
the
types
Rhesus
Rituximab cancer drug
with
antigen).
cancers.
diagnosis
cycle
different
and
suggest
treatment.
how fertility
kits
used.
155
2.8
Practice
Health
Answers to
1
a
all
Explain
b
why
c
why
does
Outline
the
the
give
most
be found on the
common
with
one
to
strain
regional
data
infectious
dengue fever
in
and
a
Describe
the
b
Explain why there
diagnosed
ways
as
in
c
the
on
of
are
HIV+
many
but do
symptoms of the diseases
c
Discuss
factors
of
3
HIV
d
diseases,
social,
being
e
such
enters T-cells
in
reverse
HIV
Suggest
similar
to
problems
to
treat
treat
that
drugs
to
treat
HIV.
to
secondary
Explain
those
in
why.
the
[2]
table
are
dengue fever.
are
likely
people
to
who
[2]
arise
are
when
living
with
HIV.
as
[2]
[3]
have
[3]
Candida albicans is a fungus that causes opportunistic
infections. The scanning electron micrograph (Figure
2.8.
1) shows a phagocyte engulng a cell of
been
C. albicans
any of the
associated with AIDS. [2]
control
by
and
of
biological
the
transmission
endocytosis. Three
transcriptase,
to
protease,
into
drugs
to
make
of
which
smaller
integrase,
of
the
are:
chromosomes

show
why
prescribed
not
developed
administering
transmitted.
people who
not
economic
the
is
are
but
[4]
template

HIV
Explain
incidence
HIV.
enzymes

how
influence
Antibiotics
[3]
health
the
immunology
infections,
dengue
another.
tuberculosis.
which
and
accompanying CD.
4
2
questions:
[2]
protection from
collecting
of
is
can
disease,
year.
importance
of
prevalence
malaria,
of
infection
not
authorities
and
dengue fever
months
Suggest
fever
and
exam-style questions
wettest
exam-style
the
is
which
DNA
to
host’s
used
to
uses viral
RNA
incorporate
into
as
a
the
cells
break
a
polypeptide
molecules
which
inserts
proviral
DNA
to
human
Figure 2.8.1
DNA.
a
The table gives information about some of these drugs.
Explain
briefly
invading
Drug
Enzyme
zidovudine
inhibited
Mode of
action
reverse
occupies
active
transcriptase
site
reverse
occupies
transcriptase
site
reverse
occupies
transcriptase
other
b
c
Describe
how
invading
cells.
Outline
how
phagocytes
microorganisms
the
such
phagocytes
recognise
as
engulf
C. albicans.
and
[2]
digest
[5]
differences
between
neutrophils
and
macrophages.
tenofovir
5
a
Outline
in
efavirenz
the
how
lymphocytes
human
protease
Severe Combined
the
(SCID)
site
occupies
and
mature
body.
is
a
rare
[4]
Immunodeciency Syndrome
inherited
T-lymphocytes fail
atazanavir
originate
sites
than
active
[3]
active
to
condition
develop
in
which
properly.
B-
Babies
and
with
active
SCID
are
susceptible
to
opportunistic
infections
such
site
as
raltegravir
integrase
binds
ions
magnesium
needed for
active
site
those
caused
by
die
early
in
b
Explain
Explain
the
difference
between
the
mode
of
zidovudine
and
People
who
receive
drug
efavirenz.
treatment for
why
babies
mixture
of
drugs
that
act
in
different
HIV
drugs
156
the
advantage
shown
in
the
of
table.
taking
a
mix
are
susceptible
to
[3]
[2]
with AIDS
are
also
susceptible
to
take
infections.
ways.
d
Suggest
with SCID
infections.
[4]
opportunistic
a
babies
Suggest how infants with SCID may be treated.
People
b
these
of
c
action
and
treated,
infancy.
opportunistic
a
Candida albicans
Pneumocystis jiroveci. Unless
of
the
[3]
Explain
how AIDS
differs from SCID.
[2]
Module
6
Figure
2.8.2
is
a
diagram
of
an
antibody
molecule.
9
Some
diseases
are
3
Applications
classied
as
both
of
biology
inherited
and
degenerative.
a
variable
Explain,
using ONE
example of
between these two
region
The
table
diseases
region
shows
the
between
as
changes
1985
collected
each, the difference
categories of disease.
and
and
in
death
2000
in
published
Disease
Mortality
condition
deaths
[4]
rates for four
the Caribbean
by CAREC.
rates/number of
constant
per
100 000
population
region
heart
disease
diabetes
a
Name the type of cell that produces antibodies.
b
State ONE function for
1995
2000
107
.2
109.5
114.0
102.5
36.2
50.0
51.9
65.0
81.
1
81.6
88.5
98.5
19.6
39.8
mellitus
the
two
component
HIV/AIDS
[1]
antibody
that
are
labelled
on
the
0.2
2.7
parts
b
the
1990
cancer
Figure 2.8.2
of
1985
i
Calculate
the
percentage
change
in
the
death
diagram.
rate for
diabetes
mellitus
between
1985
and
[2]
2000.
c
Explain
why
part
of
the
antibody
molecule
ii
known
as
the variable
[1]
is
region.
Suggest
death
7
T-lymphocytes
cell
a
surface
Explain
have
special T-cell
receptors
on
their
signicance
of
these
receptor
d
[3]
Distinguish
and
between
lymphocytes
on
the
responses
the rst
and
of
of
the
same
strain
of
a
The
table
analysed
of
[6]
the
increase
between
shows
show
diseases
in
1985
as
how
the
the
and
only four
Explain
to
change
in
the
death
rate for
2000.
types
of
the gures
relative
leading
[2]
[3]
disease
should
importance
causes
of
death
be
of
in
each
the
[2]
a
Distinguish
between
the following
pairs:
bacterial
antibody
and
antigen;
humoral
and
cell-mediated
[3]
immunity;
Describe
the
mellitus.
Caribbean.
phagocytes
pathogen.
d
the
diabetes
repeated
10
infections
Account for
condition.
Name THREE different types of T-cells and
outline their roles in defence against pathogens.
c
rate for
HIV/AIDS
molecules.
b
c
membranes.
the
explanations for
[3]
one
example
of
each
of
primary
and
secondary
immune
the following
responses.
types
of
immunity:
natural
active,
articial
b
natural
passive,
articial
passive.
Outline
Soon
after
the rst
a
pathogen
time,
antibody
the
enters
blood
molecules,
the
contains
each
human
many
produced
by
body for
c
different
a
of
roles
of
mast
cells
and
complement
defence.
Explain
[4]
how
molecule
is
the
structure
related
to
of
an
antibody
its function.
[5]
different
11
group
the
[4]
in
8
[6]
active,
The
body
produces
many
different
clones
of
B-
and
cells.
T-lymphocytes.
a
Distinguish
between
the
terms
pathogen and
antigen.
b
Explain
a
State
the
b
Describe
c
Outline
meaning
of
the
term clone.
[1]
[2]
why
the
response
is
a
the
origin
of
these
clones.
[3]
polyclonal
response.
[3]
how
clones
of
specic T-lymphocytes
develop.
c
Explain
the
why
blood
infection
Monoclonal
and
d
much
by
the
antibodies
are
sooner following
same
antibodies
present
a
d
subsequent
pathogen.
are
produced for
[4]
in
[2]
Name
the
outline
cells
the
that
roles
of
produce
antibodies
antibodies.
and
[6]
diagnosis
treatment.
Explain
the
diagnosis
e
these
Outline
advantages
and
how
pregnancy
of
using
antibodies
in
treatment.
monoclonal
testing
and
[3]
antibodies
cancer
are
used
treatment.
in
[6]
157
3
Applications
3.
1
Diet
and
are
completion
should
be
able
of
this
section,
you
the
and
the
encouraged
are
term
eat
are
dene

outline
in
components
of
in
increasing
we
healthy.
many
and
The
countries
as
need
t
people
to
active
results
people
become
satisfy
our
of
ways
in
neglecting
are
getting
more
needs
are
and
and
which
this
we
sensible
heavier
.
more
neglect
overweight.
to
If
exercise,
energy
is
stored
as
fat
in
adipose
tissue.
People
who
are
such
the
term
how
malnutrition
overweight
diets
the Caribbean
early
1950s
state
the
have
obesity
links
and
problem
increased
are
categorised
as
obese.
Obesity
is
risk
since
the
between
diet,
food
survive.
disease.
have
a
we
If
foc us
The

and
exercise form
part
denition
of
discussion
health?
about
We
Look
health
on
that
Sufcient
page
you
128
and
wrote
see
needs
if
just
cardiovascular
diet.
a
Many
varied
our
us
a
energy
of
and
it
is
associated
diseases,
variety
meet
of
an
emerging
with
cancers
achieve
to
nutrients
nutrients
this
require
balanced
to
a
these
people
diet
bodies
of
with
enough
carbohydrates,
and
an
arthritis.
this
supplies
function
to
that
meet
without
the
we
our
much
energy
need
needs
to
we
conscious
and
the
efciently.
diet:
fats
our
and
energy
requirements.
proteins
in
our
food.
It
This
is
is
provided
by
recommended
back
fat
does
not
provide
more
than
35%
of
total
energy
intake,
with
and
fat
providing
no
more
than
10%
of
total
energy.
Rened
the
sugars
denition
provides
eat
eat
saturated
disease
because
of
that
the
eat
we
components
the
your
countries
diabetes,
balanced
chemicals
diet
of
many
Balanced diet
thought.
S tudy
in
changed
region
The
at
remain
keeping
diet

Did
and
balanced diet
health

to
than
signicantly
a
diet
obvious:
more
excess
list
balanced
W
aistlines
to:
explain
a
advice
we

biology
disease
Eating
Learning outcomes
On
of
(sucrose)
should
not
be
more
than
10%
of
the
total
energy
amending
intake.
to
include
these
two
important

The
eight
to
ten
essential
amino
acids
(EAAs).
These
are
provided
by
aspects.
the
protein
must
be
in
in
our
the
diet.
diet.
EAAs
cannot
Without
them,
be
synthesised
proteins
are
by
not
our
cells
and
synthesised
properly.

Essential
fatty
linolenic
acid.
membranes.
quantities

W
ater
acids
We
are
soluble
(EFAs) .
They
are
cannot
There
needed
to
E,
K.
vitamins,
Vitamins
quantities
make
NADP

S tudy
and
Minerals,
food
synthesise
a
great
required
more
about
the
roles
e.g.
,
B
water
many
biology
and bre.
relate
that
Find
you
to
other
have
aspects
studied.
in
the
water
revise
body
when
W
ater
the
roles
of
Na
and
and
we
how
get
we
conserve
dehydrated

Fibre
not
5.4
and
is
required
6.2
in
Module
solvent
(non-starch
helps
with
prevent
either
.
Only
acid
and
for
very
small
B
or
,
C,
and
fat
soluble
vitamins,
e.g.
A,
2
cannot
synthesise
such
as
the
required
them,
in
but
very
need
coenzymes
small
them
FAD,
to
NAD,
A.
iron
as
of
and
part
of
functions.
functioning
not
and
only
for
iodine.
organic
These
are
absorbed
compounds.
Sodium
of
the
to
prevent
and
They
potassium
nervous
system
dehydration
temperature
polysaccharides)
and/or
its
absorbed.
movement
constipation.
reduce
from
are
our
required
ions
(see
are
page
122).
but
also
as
a
regulation.
energy
It
along
also
intake.
is
material
Instead
the
gives
There
a
it
gut
gives
by
sense
is
of
developing
intestinal
diseases.
from
bulk
plant
to
our
peristalsis,
of
‘fullness’
evidence
2).
chances
158
We
calcium,
proper
digested
helps
(see
linoleic
of
For
+
K
–
out
+
example,
these
compounds
substances,
ions
variety
for
reactant,
how
day.
organic
coenzyme
as
these
of

nutrients,
are
vital
e.g.
either
of
phospholipids
foc us
for
Read
each
certain
two
required.
1
D,
are
make
that
it
food
that
food,
helping
after
to
eating
reduces
is
which
the
so
Module
The
quantities
such
as
age,
women,
energy,
whether
Allowances
dietary
of
gender
,
that
advice
they
you
are
nutrients
occupation,
are
and
levels
pregnant
might
nd
quantities
or
on
water
of
vary
exercise,
according
climate
breastfeeding.
packets
sufcient
for
of
food
most
of
to
factors
and,
or
in
Applications
of
biology
Link
for
Recommended
the
3
leaets
Daily
with
You
can nd
information
different food
population.
more,
on
the
Caribbean
groups,
website
Food
and
about
and
of
the
much
the
Nutrition
Institute.
Malnutrition
For
are
many
too
people
poor
to
a
balanced
afford
diet
enough
of
is
impossible
the
staple
for
foods
economic
that
reasons
provide
–
energy,
they
such
S tudy
as
rice,
foods,
our
and
bread.
particularly
Their
fresh
fruit
diet
and
is
unlikely
vegetables,
to
contain
that
the
provide
variety
the
foc us
of
vitamins
and
Find out what diseases are categorised
minerals
we
need
to
protect
us
from
deciency
diseases.
Even
apparently
as diarrhoeal diseases
well-fed
people
may
have
a
low
intake
of
a
specic
nutrient
such
as
and then
iron,
answer Summary question
which
foods
leads
from
reduction
The
to
iron-deciency
the
of
different
energy
nutrition
of
food
intake
most
anaemia
groups.
as
they
are
Malnutrition
happens
populations
as
when
in
the
not
is
people
eating
more
suffer
Caribbean
2.
sufcient
than
the
starvation.
has
improved
Summary q uestions
signicantly
great
since
the
improvement
living
standards.
malnutrition
1950s.
in
food
This
and
is
Over
supply,
reected
diarrhoeal
that
period
education
in
the
diseases,
of
about
decrease
both
time
of
there
food
in
has
and
been
a
general
1
childhood
which
used
to
Explain
the
be
causes
what
terms
is
meant
by
balanced diet and
of
malnutrition
high
rates
of
infant
improvements
desperately
associated
are
poor
,
with
and
not
childhood
uniform.
with
children
poverty,
many
morbidity
Parts
and
of
of
the
adults
which
and
mortality.
Caribbean
suffering
are
related
are
from
to
These
2
still
the
poor
a
Give
explain
diet.
b
At
the
other
extreme,
unbalanced
diets
may
provide
too
much
two
examples
deciency
diseases
Give
diseases
their
two
this
change
in
diet
in
the
Caribbean
have
come
the
diseases
examples
not
rich
meat
in
energy
of
dense
populations
saturated
better
poverty.
and
and
like
fat,
food
those
supply,
obesity
products
provides
sugar
,
manufactured,
The
dairy
far
more
elsewhere
salt
and
which
is
convenience
in
low
a
epidemic
that
in
good
foods
is
increase
energy
the
is
but
not
the
intake
people
are
Partly
thing,
that
than
world
bre.
partly
the
also
has
by
good.
fat,
need.
eating
this
result
of
of
diets
c
is
include
a
variety
of
fruits
and
Explain
high
in
about
why
mortality
has
by
infant
in
has
prevalence
become
that
it
is
an
decreased
since
region.
epidemic
now
Currently,
the
about
have
neglected
Discuss
in
most
the
Caribbean,
important
with
underlying
such
increasing
the
differences
cause
of
death
modern Western
25%
of
adult
women
in
many
countries
which
is
is
an
almost
twice
emerging
and
as
many
as
extremely
adult
men.
worrying
Obesity
and
diets.
in
Explain
the
eating
effects
diets
on
rich
in
health
saturated
among
fat
children
between
diets
are
of
obese,
the
vegetables.
4
the
and
the Caribbean
traditional Caribbean
Obesity
and
morbidity
1950s.
eating
People
state
causes.
childhood
3
to
of
and
diets
which
Caribbean
come
diseases
of
their
plenty,
causes.
energy.
diarrhoeal
With
of
and
and
rened
sugar,
but
low
in
problem.
bre.
5
‘Nothing
better
difference
as
the food
whether
they
you
statement
or
inequalities
addressed
6
Outline
by
the
take
reduce
Figures 3.1.1 and 3.1.2
to
the
rich
eat’.
agree
not.
the
and
poor
Explain
with
this
Suggest
in food
supply
how
can
be
governments.
steps
governments
can
illustrates
between
in
that
the Caribbean
improve
diets
prevalence
of
and
diet-
See how we have grown? In the 1950s and 1960s obesity was
rare. Now it is very common. The mismatch between energy input and energy output is
related
diseases.
responsible for the obesity epidemic.
159
3.2
Fats
in
the
Learning outcomes
On
completion
should
be
able
of
this
section,
you
diet
Fat
is
are
absorbed
form
describe
the

diet
outline
what
after
of
happens
it
how fat
is
to fat
blood
and
blood
explain
plasma.
they
circulate
where
are
they
small
molecules
that
Chylomicrons
fatty
acids
are
travel
in
into
composed
them
the
glycerol,
reformed
particles
make
and
soluble
lymph
to
of
in
the
which
fat
a
in
core
the
the
of
fat
lymph
and
Also
absorbed
are
then
absorbed
by
the
blood
where
liver
.
is
transported
from
the
intestine
and
transported
in
chylomicrons
is
in
Liver
cells
also
make
cholesterol,
which
is
transported
to
cells
transferred
require
it
in
lipoproteins .
These
are
smaller
but
similar
to
organs
how
atherosclerosis

very
low
There
density
are
several
different
lipoproteins
types
(VLDLs)
of
carry
lipoprotein:
fat
for
storage
in
adipose
tissue
outline
the
associated
health
with
risks
atherosclerosis

low

high
density
take

cells
These
into
absorbed
occurs

intestine
epithelial
protein
chylomicrons.

small
in
that
between
the
into
by
cholesterol.
the
in
chylomicrons.
surrounded
to:
and

digested
describe
the
different
cardiovascular
types
lipoproteins
density
it
to
(LDLs)
lipoproteins
the
liver
for
carry
(HDLs)
excretion
cholesterol
remove
in
the
from
the
cholesterol
liver
from
to
tissues
tissues
and
bile.
of
disease.
Y
ou
need
between
all
of
these
them.
cardiovascular
lipoproteins,
People
with
diseases
high
than
so
doctors
ratios
those
of
with
tend
to
monitor
LDLs:HDLs
low
are
the
more
ratio
at
risk
of
ratios.
Link
To
better
understand
the
context
Fat
is
the
kidneys
section
about fat,
it
would
be
idea
to
revise
the
In
lipids from Unit
1.
1
in Unit
tissue,
heart,
for
and
example
around
the
underneath
intestine
the
skin,
(visceral
or
around
abdominal
The
any
site
excess
of
carbohydrate
deposition
of
fat
and
is
protein
is
important,
converted
since
into
people
fat
with
biochemistry
See
1.5
abdominal
fat
(‘beer
bellies’)
are
more
at
risk
of
cardiovascular
of
diseases
Module
the
addition,
stored.
much
of
adipose
a
and
good
in
and
of
fat).
this
stored
than
those
with
the
fat
on
their
hips
(‘pear-shaped
bodies’).
1.
Atherosclerosis
Did you know?
LDLs
penetrate
breaks
The
density
of
lipoproteins
refers
or
they
speed
HDLs
to
in
settle
a
centrifuge.
sink,
their
when
spun
Put
content
high
simply:
LDLs oat! This
relative
at
of
is
may
related
lipids.
cells’.
This
walls
and
of
begin
3.2.1).
lumen
which
This
endothelium
block
ow
often
of
atheroma
The
endothelial
result
in
of
found
the
blood
high
tissue
blood
as
developing
the
may
less
inside
be
a
that
lines
pressure.
arteries.
Here
form
you
can
see
in
a
all
in
high
children
and
smooth
and
less
blood
in
of
the
able
is
to
clot
of
it
increase
artery
ow
The
LDLs
forms
the
plaques
or
blood
in
a
by
of
is
properly.
The
plaques,
thrombus.
an
wall
Figure
roughened
through
in
the
arteries
(see
function
‘foam
and
plaques
width
disrupted
give
form
muscle
plaques
to
to
surface.
When
artery
with
table.
are
blood
as
of
development
the
atherosclerosis
macrophages
atheroma
plaques
endothelium
block
and
growth
healthy
can
fat
by
deposited
elastic
the
to
is
the
The
it
for
saturated
time,
lumen.
platelets
engulfed
material
through
occurs
is
promote
With
become
factors
which
Calcium
break
results
risk
high
of
stimulates
drastic
also
arteries.
to
thrombosis
in
the
the
accumulated
Arteries
smooth
calcium
be
cholesterol,
Macrophages
bres.
the
their
atherosclerosis .
build-up
in
to
deposit
how
tears
breaks
smoking,
pressure.
young
as
lack
Fatty
of
exercise,
streaks
have
a
diet
been
seven.
deposits
vessel
walls
Link
This
is
an
opportunity
especially
reduced
revise
how
the
their
structure
role
in
and function
delivering
blood
lumen
constricts
blood
flow
Figure 3.2.1
160
to
arteries. Think
Atherosclerosis
pressure
will
be
affected
by
the
build-up
of fatty
plaques.
of
to
blood
vessels,
tissues
at
high
Module
3
Applications
of
biology
Cardiovascular diseases
These
they
diseases
are
of
the
inuenced
heart
by
and
many
Cardiovascular
Region
disease
affected
hypertension
whole
coronary
heart
heart
circulatory
factors
and
system
there
is
are
no
multifactorial
one
underlying
as
cause.
Symptoms
body
none
(at
angina
disease
least
pectoris
during
–
many
severe
years)
chest
pain
often
exercise
heart failure
to
not for
pump
–
weaker
blood
heart
gradually fails
efciently
Figure 3.2.2
A cross-section of a
coronary artery in which an atheroma is
myocardial
sudden
infarction
and
necessarily
severe
(heart
chest
related
to
attack)
pain,
–
obstructing most of the lumen (× 10)
not
exercise
Link
stroke
(cerebral
brain
speech
slurred
(or
no
speech
at
all) face
Here
infarction)
drops,
not
able
to
raise
an
arm
(or
is
another
category
of
disease.
both
This
group
of
diseases
all
affect
the
arms)
same
Hypertension
Hypertension
pressure.
At
is
a
rst
condition
there
may
in
be
which
no
the
patient
symptoms,
but
has
high
there
is
system
of
the
would
you
classify
table?
See
page
body.
the
How
diseases
else
in
the
129.
blood
a
higher
risk
of
Summary q uestions
damage
occurring
atheroma
and
to
the
increases
artery
the
walls.
chances
This
of
stimulates
developing
the
development
angina
or
of
suffering
1
from
a
stroke
or
heart
attack.
High
blood
pressure
is
more
likely
in
Dene
the
disease,
who
smoke,
are
overweight,
drink
and/or
salt
excessive
alcohol,
take
little
terms
plaque,
eat
a
high
fat
high
diet.
The
normal
blood
atherosclerosis,
exercise,
hypertension,
or
cardiovascular
people
pressure
for
stroke,
coronary
a
heart disease
young
adult
pressure
and
a
is
about
above
diastolic
Coronary
13.3
16.0
kPa
pressure
kPa
systolic
increases
above
the
17.3
and
risk
kPa
is
10.7
of
kPa
diastolic.
cardiovascular
considered
to
be
A
diastolic
2
problems,
very
serious.
3
heart disease
Outline
what
the
after
Explain
the
The
the
two
coronary
aortic
coronary
these
to
heart
arteries,
some
heart
valve.
of
has
is
heart
work
a
branch
of
disease .
there
the
to
arteries
Disease
If
these
a
from
blockage
reduction
tissue,
harder
in
which
to
the
arteries
force
base
occurs
the
may
blood
of
the
supplying
within
supply
lead
to
of
a
the
just
cardiac
branch
oxygen
death
through
aorta,
the
of
and
the
one
4
nutrients
tissue.
coronary
is
of
The
blood
pressure
increases.
Also
the
cardiac
output
does
arteries
not
Explain
during
times
of
high
demand,
such
as
during
why
(cerebral
stroke
burst
and
occurs
with
their
brain
and
is formed
in
a
cholesterol
body;
it
and
b
cells
is
in
is
the
transported
with
in
protein.
and
Outline
the
in
effects
the
wall
of
of
a fatty
an
artery
on
exercise.
of
blood.
infarction)
when
leakage
nutrients
in
increase
6
A
to fat
artery.
to
the ow
Stroke
plaque
an
transported
deposit
sufciently
of
combination
5
so
how
wall
happens
ingestion.
above
muscle
of
diet
an
into
may
artery
brain
die.
compensates
for
or
arteries
tissue.
People
the
The
who
in
the
brain
tissue
survive
functions
that
brain
is
strokes
they
are
blocked,
starved
often
have
of
nd
Describe
the
long-term
consequences
or
accumulating
oxygen
that
lost.
7
a
coronary
b
arteries
Find
the
of fatty
in
arteries
arteries,
in
the
deposits
in
and
brain.
risk factors for
coronary
Did you know?
Cardiovascular
Caribbean
as
diseases
in
many
are
other
the
most
parts
of
important
the
world.
cause
of
death
in
the
heart
disease
them
and
and
identify
preventable
and
stroke.
which
which
List
are
are
not.
161
3.3
Investigating
Learning outcomes
completion
of
this
section,
be
able
ways
dene
and

the
terms
aerobic exercise
aerobic fitness
describe
the
of
the
others
effects
muscular,
or
that
As
of
in
their
the
gas
or
explain
effects
exchange
are
how
of
encouraged
now
tend
to
to
do
maintain
less
good
physical
health
activity
are
as
diet
part
of
and
their
the
there
activities.
solitary
is
a
This
exercise
need
may
to
be
include
regular
an
exercise
routine
participation
in
as
sport
part
with
routines.
best
type
of
exercise
to
carry
out
provides
activity
for
the
heart,
cardiovascular
immediate
exercise
system
and
the
gaseous
exchange
system.
This
type
of
systems
exercise

are
home,
weekly
circulatory
and
we
people
exercise
The
on
exercise
to:
work

of
you
exercise.
should
effects
Aerobic fitness
T
wo
On
the
on
the
body
tissue
is
so
they
weightlifters
demands
investigated.
known
within
aerobic
respire
and
they
the
provide
as
time
it
oxygen.
aerobically,
eld
make
athletes
on
is
exercise
their
not
not
bodies
is
for
are
for
exercise
oxygen
is
provided
anaerobically.
exercise
possible
Aerobic
as
very
for
the
long
body ’s
term
periods
not
of
time.
endurance
systems
and
muscle
Sprinters,
short
power
to
does
to
respond
not
The
and
involve
and
the
Link
expenditure
everyday
Work
that
of
out
all
occur
aerobic
of
in
the
the
other
body
at
exercise. This
opportunity
to
cardiovascular
revise
82
to
the
is
a
good
aspects
physiology.
start
of
Aerobic
fitness
cardiovascular
is
assessed
you
is
a
per
than
unit
time.
explosive
measurement
and
gas
exchange
tness
are
harder
phosphate
about
exercise
includes
walking
How
to
much
everything
marathon
do
you
do?
from
run
or
than
so
myoglobin
running.
energy
better
In
terms
of
tness
for
exercise.
scores
of
the
body ’s
systems
like
the
to
one
ability
provide
to
use
oxygen
described
the
to
muscles.
It
here.
to
take
part
in
an
endurance
event,
such
as
a
97
.
Did you know?
brisk
far
See
much
from
much
is
with
long-distance
Aerobic
as
it
changes
Imagine
pages
of
life,
the
(see
swim.
before.
rates
page
haemoglobin
responds
dioxide
concentration
and
rate
output
of
transport
to
oxygen
in
to
this
the
the
start,
soon
This
does
more
muscle
body
blood
not
last
The
the
it
for
is
lungs
also
long
creatine
by
available
either
,
in
so
the
carbon
in
the
oxygen.
per
working
and
stored
increase
more
begin
A
TP
is
increase
an
with
to
their
Oxygen
available;
stimulates
the
muscles
exhaust
becomes
blood
your
increase.
anaerobically.
provide
provide
to
very
blood.
respiring
breathing
increases
and
the
muscle
They
you
respiration
165)
in
by
of
When
depth
The
unit
cardiac
time
to
tissues.
Step tests
Y
ou
can
test
that
Figure
Figure 3.3.1
Aerobic steps; you can use
investigate
to
assess
2.7.4
on
laboratories
to
the
effect
aerobic
page
32
assess
of
shows
the
exercise
on
the
body
by
carrying
out
a
tness.
the
tness
apparatus
of
athletes.
used
This
by
exercise
shows
the
physiology
sorts
of
something similar in a step test
measurements
easiest
to
recorded
work
and
this
or
you
As
it
is
page
Figure 3.3.2
There is no excuse for not
taking enough exercise. You can even play
tennis with the help of a games console.
162
like
by
be
heart
It
during
this
and
also
at
taking
with
before,
blood
helps
exercise
machine
by
made
a
–
if
ngers
pressure
you
say
tness
your
during
by
can
after
monitors
measure
using
centre.
pulse
and
It
a
is
over
with
the
treadmill,
difcult
measurements
placed
exercise.
pressure
the
It
amount
an
to
points
of
exercise
take
during
is
data
precise
an
(see
Figure
88).
unlikely
determining
exercise
with
results
investigation
on
do
rowing
reliable
3.4.1
can
electronically.
that
bicycle
do
that
that
aerobic
doing
a
you
have
tness
step
access
you
test.
can
to
sophisticated
investigate
the
equipment
immediate
for
effects
of
Module
Apparatus:
Y
ou
need
may
be
This
a
box,
able
to
stair
or
borrow
photograph. Y
ou
also
bench
an
about
aerobic
need
a
250 mm
step
like
high. Y
ou
the
one
in
of
the
timer.
is
a
very
aerobic
you
simple
fitness
information
could
modify
aerobic
or
test. Y
ou
you
based
the
test
exercise,
3
can
on
Applications
may
age
and
yourself
such
as
know
search
to
for
of
biology
other
others
body
use
shuttle
of
tests
that
give
mass. Y
ou
another
form
of
runs.
Safety:
T
ake
some
exercise
continue. Y
ou
four
times.
over
40,
can
Then
then
it
first
to
walk
take
is
ensure
up
your
not
a
and
pulse
good
that
down
for
idea
it
is
safe
some
15
to
Y
ou
stairs
seconds.
to
continue
of
breath
three
If
it
with
or
is
can
takes
This
If
you
are
numb,
dizzy
or
out
then
the
period
use
of
do
the
test.
Do
not
carry
out
any
investigation
if
you
sure
if
the
person
doing
the
exercise
is
free
of
much
find
condition
that
might
put
them
at
in
are
thoroughly
rested
and
then
take
pulse.
Do
this
three
times
and
can
Start
with
both
feet
on
the
take
an
Step
up
•
Step
down
and
put
who
both
put
feet
both
Practise
stepping
seconds
Carry
out
to
step
the
up
up
on
the
feet
and
and
procedure
long
it
value.
time.
to
achieve
fitness? Y
ou
can
an
simply
the
use
take
the
resting
step
test
pulse
a
fitness
programme
and
see
at
if
any
significant
not
take
improvement,
it
much
use
exercise.
took
of
a
a
number
student
of
different
who
ran
on
a
treadmill
in
floor.
step
or
exercise
on
the
down
The
until
very
it
takes
you
in
much
the
admitted
to
not
exercise
each
week.
The
results
are
table.
2
Measurement
have
student
box.
down.
you
laboratory.
floor.
shown
•
also
does
physiologist
taking
and
how
resting
average.
an
•
record
the
recovery
necessary
during
show
measurements
•
to
your
A
resting
is
aerobic
intervals
someone
you
but
risk.
Procedure:
sure
the
test,
return
any
decreases. T
o
Make
is
exercise
out. Y
ou
regular
medical
time
to
are
to
not
same
rate
not
improvement
do
the
pulse
the
How
test.
also
for
practised
for
At
rest
During
During
strenuous
recovery
4
exercise
minutes
without
taking
any
rests.
3
When
you
finish,
•
Rest
for
1
•
Rest
for
another
stay
minute
standing
and
take
tidal
up.
your
pulse
for
15
seconds
and
take
your
3.3
1.7
seconds.
breathing
45
0.5
volume/dm
pulse
rate/
again
12
24
18
80.0
30.6
–1
breaths min
for
15
seconds.
3
ventilation
•
Repeat
again,
so
you
have
three
readings
of
pulse
(volume
for
the
3
minutes
after
you
finished
the
rate/dm
–1
min
6.0
rate
of
air
breathed
exercise.
in
during
1
minute)
Results:
pulse
Multiply
each
pulse
rate
by
four.
Calculate
the
sum
of
three
pulse
rates
your
(in
fitness
70
190
120
minute
).
beats min
aerobic
per
the
–1
calculate
rate/beats
Use
this
figure
to
systolic
score:
blood
pressure/
15.0
26.1
21.0
10.0
10.5
10.5
kPa
24 000
___________________
aerobic
fitness
score
=
diastolic
total
number
of
blood
pressure/
beats
kPa
Compare
your
Aerobic
score
fitness
against
the
score
table.
Category
of
fitness
S tudy
less
than
61
61
to
70
average
71
to
80
good
81
to
90
very
Look
carefully
90
at
the
physiologist.
Make
Then
each
look
at
measurements
sure
one
that
in
you
turn
taken
know
and
see
by
what
what
the
they
all
are.
has
good
happened
over
foc us
poor
during
and
after
exercise. You
can
do
some
excellent
simple
calculations, for
exercise
was
Summary
double
question
example
what
it
was
breathing
at
rest.
rate
Now
during
answer
2.
Summary q uestions
1
2
Outline
the
immediate
following
systems
exchange
and
a
of
effects
the
body:
of
exercise
muscular;
on
4
the
gaseous
the
results
in
physiologist
the
cardiovascular.
Summarise
A
tness
the
a
table.
planned
improvement
Explain
Suggest
what
the
changes
you
have
described
in
terms
physiology
of
the
Outline
a tness
programme
that
the
student
to
improve
compare
different
should
can
be
be
done
made
to
ensure
between
the
that
valid
people
different tness
programmes.
Explain
how
you
would
monitor
aerobic tness
could
during
follow
to
during
student.
b
3
investigation
of
following
the
an
aerobic tness
programmes.
comparisons
b
in
the
investigation.
aerobic tness.
163
3.4
Exercise
Learning outcomes
and
Assessing fitness
A
On
completion
of
this
health
section,
measure
absorb
should
be
able
of
and
state
VO
the
meaning
of
the
term
max
explain
tness
oxygen.
This
is
the
is
maximum
the
max.
VO
rate
at
which
Exercise
the
body
can
physiologists
2
intensity
and
2

use
to:
determine

aerobic
you
how VO
max
of
on
volume
exercise
gradient
person
is
this
of
the
an
of
oxygen
increases.
exercise
treadmill
is
by
measuring
This
can
treadmill.
measured
be
The
with
the
done
oxygen
a
gas
oxygen
by
uptake
increasing
the
consumption
analyser
and
of
the
as
the
speed
the
results
2
plotted
determined

explain
the
term
cardiac
on
a
graph
max
The
VO
that
most
is
people
sophisticated
state
be
how
much
undertaken
exercise
to
aerobic tness
state
benecial
good
in
Figure
indicator
of
3.5.2
the
on
level
page
of
166.
are
ever
laboratory
going
to
determine
tness.
apparatus
available
for
But
it
is
to
themselves
not
an
exercise
using
one
the
physiologist.
should
improve
maintain
that
2
efficiency

a
like
and
However,
there
is
a
cor relation
between
max
VO
and
heart
rate,
so
it
is
2
possible
to
use
measurements
working
at
their
max
VO
or
of
at
a
pulse
rate
to
proportion
assess
of
it.
when
This
is
someone
important
is
in
2

the
effects
of
designing
exercise
on
the
 tness
programmes
that
will
improve
aerobic
 tness.
See
cardiovascular,
below.
gas
exchange,
muscular
and
Cardiac
skeletal
in

efficiency
is
the
ratio
between
the
work
done
by
the
left
ventricle
systems
explain
how
chronic
diseases.
exercise
can
pumping
blood
and
the
volume
of
oxygen
consumed
by
cardiac
prevent
muscle.
digital

Sit
This
also
is
difcult
blood-pressure
on
a
chair
pressure

Place

Pump
the
blood

Also

Now
and
up
and
relax
heart
cuff
the
of
rate
the
cuff
to
monitor
for
determine,
it
is
10
just
minutes.
before
release
it
to
to
if
Be
have
this
access
to
a
technique:
prepared
to
measure
blood
up.
monitor
record
you
use
standing
blood-pressure
and
but
possible
on
the
the
upper
systolic
and
arm.
diastolic
pressures.
record
stand
Someone
with
the
up
heart
and
good
rate.
immediately
cardiac
repeat
efciency
the
should
measurements.
see
an
increase
in
all
three
measurements:

Systolic

Heart
rate
Increases
results
less
is
Gaseous
are
provides
Figure 3.4.1
Aerobic exercise can be
should
than
an
benecial
These
diastolic
indicate
Exercise
of
and
a
these
serious
essential
effects
some
of
surface
pressure
increase
on
exchange
a
blood
the
for
by
10
indicate
part
of
three
to15
poor
problem
should
beats
cardiac
with
the
of
per
by
10
to
15 mmHg.
minute.
efciency;
decreasing
heart.
maintaining
systems
increase
the
good
health.
It
has
a
number
body.
system
effects
the
air
and

increase
in
tidal

increase
in
ventilation
that
exercise
diffusion
of
has
oxygen
on
and
the
system
carbon
that
dioxide
between
blood:
creative and fun
each
S tudy
is
a
good
idea
to
know
at
least
increase
effects for
each
–
the
of
volume
air
of
in
air
each
that
breath
enters
the
lungs
in
vital
out
capacity
after
taking
–
the
a
deep
maximum
volume
of
air
that
is
breath
increase
in
reserve
volumes
–
the
volume
of
air
breathed
in
after
a
system.
normal
164
rate
volume
two

three
the
minute
breathed
or
–
foc us

It
volume
breath
and
the
volume
breathed
out
after
a
normal
breath
Module
These

are
possible
improved
thanks
uptake
of
to
better
oxygen
by
use
of
the
gaseous
diaphragm
exchange
in
and
the
ribcage.
is
achieved
by
increases
in
the
elasticity
of
the
during
inspiration
to
give
a
larger
surface
alveoli;
area
for
they
is
also
an
increase
in
the
number
of
capillaries
group
gas
vitamins
The
maximum
rate
of
oxygen
uptake
is
around
achieved
more
these
the
These
are
supplies
some
of
quickly.
is
muscles
system
the
coenzymes:
NAD,
not
with
the
that
oxygen
exercise
they
has
require
on
the
for
system
aerobic
to
nicotinic
riboavin for
the
that
FAD
and
to
coenzyme A.
just
consumption
you
vitamins
food
respiration:
acid for
enough
exercise;
effects
needed
alveoli.
energy
Cardiovascular
are
exchange;
pantothenic

biology
expand
acid for
there
of
Did you know?
make
more
Applications
alveoli
B
This
3
and
also
and
increase
if
you
need
to
or
not
take
consider
minerals
whether
It
your
in
to
your
take
supplements.

decrease
Resting
in
heart
resting
rate
is
heart
one
of
rate
the
best
indicators
of
aerobic
tness.
S tudy

increase
heart
in
with
stroke
each
volume
–
the
volume
of
blood
pumped
out
of
foc us
the
beat
Blood-pressure

increase
in
cardiac
output
–
the
volume
of
blood
pumped
out
in
in
minute,
calculated
as
stroke
volume
×
heart
mmHg
so
three
much

make
during
decrease
the
in
the
heart
exercise
resting
amount
of
in
more
a
person
systolic
work
efcient,
done
and
by
with
so
diastolic
the
the
good
as
rate
does
aerobic
blood
not
increase
tness.
pressures
–
multiply
this
used
increase
in
cardiac
are
by
some
of
the
effects
that
exercise
has
on
the
system
that
medical
mmHg
to
kPa,
0.
133.
foc us
exercise
on
the
also
and
glucose
to
provide
the
energy
to
generate
A
TP
rest
of
has
the
benecial
body
ligaments,
by
tendons
and
for
reducing
the
blood
contraction:
cholesterol
increase
used
in
increase

increase
there
in
the
size
of
muscle
bres
and
the
gross
size
of
the
muscles
exercise


the
convert
uses
bones;

results
of
system
glycogen
muscle
give
unit
efciency.
strengthen
fat,
the
heart
effects
These
is
lowers
Aerobic
Muscular
by
profession. To
S tudy

that
rate
pressure
These
monitors
each
is
in
in
an
increase
requires
of
respiratory
increase
in
concentration;
total
overweight
number
two
mitochondria
enzymes
in
glycogen
these
decreasing
the
and
and
number
fat
as
muscle
coenzymes
of
stored
substrates
in
tissue
–
blood
these
must
increase
if
in
muscle
sources
of
–
aerobic
energy
pressure
hypertension
chronic
mitochondria
for
and
body
mass
obese;
in
those
and
in
with
decreasing
degenerative
those
decreasing
risk
of
diseases.
respiration
formation
of
Summary q uestions
A
TP

and
more
creatine
capillaries
phosphate
in
muscle
–
(see
page
capillary
33)
density
in
muscle
increases
to
1
improve
the
supply
of
oxygen
and
nutrients,
and
the
removal
a
Explain
what
is
meant
by
of
VO
max.
2
carbon

dioxide
increase
single
in
and
the
stores
polypeptide
afnity
for
lactate
of
with
oxygen
concentrations
oxygen
at
aerobic
very
haem
than
oxygen
myoglobin
as
in
its
bres;
prosthetic
haemoglobin
fall
muscle
so
signicantly.
low
partial
pressures
of
respiration
during
strenuous
tends
myoglobin
group.
to
It
keep
hold
Oxymyoglobin
oxygen,
so
has
helps
a
of
it
Outline
a
Explain
what
cardiac
efciency.
2
until
b
its
maintain
Outline
T
o
at
be
of
70%
benet,
of
your
subtracting
exercise
exercise
aerobic
is
age-predicted
your
should
age
be
from
about
maximum
220.
142
should
If
you
beats
be
heart
are
per
undertaken
17,
rate,
then
minute;
three
which
the
this
is
times
a
week
calculated
heart
rate
exercise
4
State
the
out
for
at
least
20
minutes.
This
gives
exercise
at
should
50–55%
Explain
stages
max.
Exercising
at
less
than
this
2
is
done
longer
than
20
it
meant
may
by
be
of
aerobic
occur
in
intensity
is
acceptable
so
long
regular
reduce the
aerobic
chances of
chronic diseases.
be
of
Discuss
the
benets
of
exercise
your
as
terms
of
general
wellbeing
and
it
protection
for
that
can
developing
in
VO
how
is
how taking
exercise
by
during
5
carried
determined.
mitochondria.
enough?
exercise
is
exercise.
respiration
much
it
assessed.
3
How
how
a
higher
releases
to
is
b
against
disease.
minutes.
165
3.5
Practice
Social
Answers to
1
a
all
Explain
One
way
mass
This
to
index
is
and
exam-style questions
what
is
meant
measure
by
a
obesity
exam-style
can
preventative
be found on the
balanced diet.
is
to
questions:
calculate
medicine
accompanying CD.
[1]
the
body
(BMI).
calculated
as follows:
body
mass
in
kg
_______________
BMI
=
blockage
2
(height
The
table
Body
below
mass
shows
the
in
BMI
index
m)
categories.
Category
Figure 3.5.1
20
underweight
b
20–25
Heart
disease
Discuss
acceptable
reduce
the
is
a
steps
risks
major
that
of
cause
of
ill
individuals
developing
health.
can
heart
take
[4]
overweight
c
Explain
how
benets
over
30
obese
over
40
very
3
Figure
3.5.2
athlete
maximum
programme
Before
they
starting
each
on
record
as
the
consumption
intensity
consumption
is
of
oxygen
by
increases. The
max.
the VO
2
their
max
2
body
the
[5]
of
exercise
a
VO
and
of
mass.
53.3
4.5
Height/m
P
25
M
1.82
Mass/kg
78.2
68
M
1.67
81.0
R
43
F
1.75
53.3
S
57
M
1.78
131.5
T
18
F
1.47
75.3
negyxo
Q
46.7
4.0
40.0
3.5
md/ekatpu
Gender
3
Age
nim
1–
Person
negyxo
exercise
club.
the
someone
exercise.
mc/ekatpu
and
a tness
shows
convince
regular
33.3
3.0
26.7
2.5
30.0
2.0
1.5
13.3
1.0
6.7
3
diet
join
would
gk
people
you
taking
1–
Five
of
obese
an
height
to
disease.
nim
25–30
the
1–
below
0
0
0
b
i
Calculate
the
ii
the
BMI for
each
of
the
people
people
with
in
would
the
group?
reference
information
you
in
to
Explain
each
the
give
to
each
your
person’s
of
6
8
10
12
24
26
time/min
rest
[5]
advice
4
in
table.
What
2
Figure 3.5.2
the
answer
BMI
and
a
the
table.
Use
the
[5]
the
graph
intensity
to
of
describe
exercise
the
on
effect
the
of
increasing
athlete’s
oxygen
consumption.
c
Outline
the
effects
of
obesity
on
the
health
[4]
of
individuals.
[5]
b
Explain
the
advantage
of
measuring
the VO
2
max.
2
Figure
3.5.
1
is
a
diagram
of
the
heart. There
is
c
blockage
in
one
of
the
[3]
a
Describe
i
Name
the
artery
where
the
blockage
occurred.
Explain
iii
Describe
the
what
treatment
166
[1]
how
is
the
likely
health
benets
of
is
blockage
likely
given.
to
was formed.
happen
if
to
a
low-fat
and
high-bre
diet.
[3]
has
d
ii
explain
arteries.
changing
a
and
[3]
no
[5]
Explain
the
advantages
of
eating
less
salt.
[2]
Module
4
An
exercise
minutes
same
physiologist
exercise
age,
on
height
the
and
investigated
pulse
body
rate
the
effects
of four
men
of
of
5
6
a
the
Suggest
how
exercise
so
the
physiologist
that valid
designed
comparisons
the
could
the
cardiac efciency.
[2]
ii
Explain why it is a good indicator of health.
Suggest
the factors
that
taking
up
are
likely
regular
to
[2]
prevent
aerobic
exercise.
[2]
made
results.
the four
biology
Dene
Explain
the
steps
that
health-promotion
bodies
[4]
should
Results from
of
i
people from
be
c
between
term
Applications
mass.
b
a
the
3
men
are
shown
in
the
table.
take
to
encourage
more
people
to
taking
exercise.
d
Explain
[3]
the
medical,
social
and
economic
–1
People
Pulse
rate/beats min
arguments for
encouraging
more
people
to
take
exercise.
At
rest
Immediately
after
7
A
68
[4]
exercise
A
student
designed
how
much
exercise
aerobic tness
B
74
70
105

the
Select
62
results
higher
i
show
that
the
immediately
Calculate
rate for
pulse
after
rate for
all four
Explain

Select
the
percentage
the four
increase
in
the
the
of
17
year
olds. The
the
student
as follows:
who
do
not
take
exercise
on
a
[4]
of
an
increase
in
rate
during
students
age,
body
into
pairs,
mass
and
matching
them
height.
member
of
each
pair
to
carry
out
the
programme.
pulse
men.
advantage
the
one

Train
by
at
swimming
a xed
several
speed
so
lengths
that
the
of
a
pulse
swimming
rate
the
reaches
pulse
group
men
exercise.
pool
ii
a
students
gender,
training
b
out
improve
basis.
Organise
for
was
to nd
to
81

The
of
necessary
investigation
20
regular
D
investigation
was
135
planned
C
an
98
exercise.
approximately
70%
of
the
age-predicted
[5]
maximum.
iii
Suggest
reasons for
the
differences
in
the

pulse
rates for
the four
men.
Train for
20
minutes
on
three
occasions
every
[3]
week.
c
i
Describe
how
you
would
extend
the

physiologist’s
investigation
to nd
out
Measure
at
effect
of
resting
ii
Suggest
the
regular
pulse
aerobic
exercise
on
the
you
results from
[3]
would
this
collect
extension
and
to
Another
man,
E,
investigation.
increased
i
by
joins
His
E’s
the
resting
after
pulse
subjects
pulse
the
rate
5
of
rate
the
Explain
heart
ii
the
is
minutes
45
of
immediately
health
benets
of
a
low
and
exercise.
b
a
Make
i
after
ii
healthy
artery
show
and
an
a
cross-section
artery
in
which
plaque
has
Use
the
drawings
you
made
to
of
plaque
on
the
structure
one
pulse
rate
the
describe
pulse
rate
is
advantage
rather
of
than
measuring
using
other
resting
ways
of
[1]
student
on
one
in
selected
a
regular
each
people
who
did
not
take
basis
[1]
pair followed
the
training
the
students
[1]
were
matched for
gender,
body
age
and
height
[1]
the
students
their
exercised
maximum
at
pulse
approximately
70%
rate.
[1]
the
and function
walls.
Atheroma
resting
why:
only
Suggest
how
the
student
could
analyse
the
data
of
this
investigation
to nd
out
if
[5]
there
c
the
[1]
collected from
artery
group
[5]
c
effect
whole
through
developed.
have
why
State
of
b
the
an
iv
atheromatous
of
programme
[3]
to
Explain
mass,
a
rate
investigation:
exercise
resting
rate.
drawings
this
Explain
iii
5
pulse
determining tness.
[1]
the
resting
intervals.
recorded.
exercise.
ii
In
i
[2]
30%
Calculate
a
analyse
investigation.
d
regular
men’s
rates.
how
the
the
increases
the
risk
of
blood
was
a
signicant
improvement
in
aerobic
clots
tness.
developing
in
arteries.
Explain
the
d
of
blood
clotting
in
a
coronary
artery.
Explain
Explain
how
the
risks
of
why
swimming for
20
minutes
is
better
[5]
than
d
[2]
consequences
weight
lifting for
improving
aerobic
developing
tness.
atherosclerosis
can
be
reduced.
[3]
[3]
e
State
one
muscle.
long-term
consequence
of
exercise
on
[1]
167
3
Applications
4.
1
Drugs
of
Drugs
Learning outcomes
body.
On
completion
of
this
section,
be
able
are
This
dene
the
medicinal
terms
drug and
drug

which
distinguish
illegal

between
legal
and
The
drugs
explain
they
The
biology
can
action
links
help
it
the
you
your
study
is
of
the
so
much
term
USA
S tudy
and
drugs
the
pages
the
should
lead
of
are
the
the
in
but
by
can
be
as
difcult
diseases. The
based
on
effects
body,
which
are
such
cells,
as
as
antibiotics
deal
with
tissues
cocaine,
central
and
heroin
and/or
and
the
painkillers,
These
are
and
two
our
pathogens
and
marijuana
peripheral
non-medicinal
nicotine
attitudes
drug’
many
medicinal
sold
any
the
that
their
they
legality
are
of
drugs
and
used.
the
in
legal
alcohol.
drugs
changing
are
in
nervous
drugs
Both
of
socially
response
(ganga),
systems.
that
are
these
are
very
acceptable
to
the
harm
in
that
is
often
used
to
refer
to
drugs
that
are
use.
In
often
society.
as
are
over
of
sale
but
in
as
of
there
the
are
Illegal
severe
into
drugs
Psychoactive
and
Stimulants,
functions
to
and
banned,
as
on
that
their
and
and
for
are
so
too
small
they
often
Canada.
(FDA).
to
follow
Licenses
the
for
circumstances.
many
supermarkets.
of
the
Administration
prescription;
painkillers
painkillers
Some
that
can
be
sold
in
are
also
for
places
sale
there
country
Similar
they
The
has
where
inuence
sale
licensed;
them
countries,
No
that
body.
regulations
and
the
total
yet
banned
tobacco
can
have
differ
minimum
are
restrictions
the
and
bans
be
on
the
tobacco,
smoked
been
countries.
with
severe
from
penalties
country
categorised
name
improve.
on
UK.
drugs
whole
offer
alcohol.
the
be
the
Muslim
of
vary
may
UK
number
tobacco
restrictions
Penalties
drugs
the
market
certain
on
psychoactive
Caribbean
are
consumption.
on
many
Canada
under
pharmacies
places
consumption
USA,
the
USA,
available
effects
over
In
sale
Drug
governments
on
the
governments
and
misuse.
are
alcohol
purchasers.
and/or
avoid
having
countries
introduced

restrictions
to
in
by
Food
come
their
at
the
regional
only
counter
licensed
is
that
permit
nicotine
well
consumption
age
drugs
usually
time
and
are
authorities
the
have
that
authority
Caribbean,
the
drugs
one
between
types
the
those
licensing
Alcohol
drugs
categorising
ways
in
illegal drugs
all
Antibiotics
foc us
Categorising
the
such
the
societies:
licensing
investigate
mind
on
drugs,
target
psychoactive.
used
Throughout
of
at
have
with
‘recreational
but
countries
chemical,
dr ugs ,
sections
as
studied. We
revision.
categories
reactions
covers:
specic
many
modes
drugs; following
next few
Legal
are
as
chemical
drugs
a fascinating
together
have
on
a few
the
It
brings
touch
of
on
is
effects.
that
only
inuence
do.
Legal
as
or
foc us
Pharmacology
their
modify
therapeutic
societies,
illegal,
subject
few
in
categorised
drug tolerance
S tudy
or
on
interact
next
common
many
and
act
psychoactive
abuse

denition
that
to:
which

substances
you

should
biology
as
suggests,
Examples
of
to
for
sale,
dealing
and/or
country.
follows:
cause
these
mental
drugs
and/or
are
physical
nicotine,
caffeine,
Did you know?
amphetamines
and
Drugs
once
that
sold
(from
are
and
which
now
used
heroin
illegal
cocaine
are
wakefulness.
that
have
is
prepared)
good
examples
an
Second
Their
World
effects
W
ar
may
pilots
include
used
to
greater
take
alertness
amphetamines
were
to
help
to
concentrate,
them
stay
Hallucinogens
interesting
as
awake.
do
Smokers
cause
many
coffee
maintain
changes
in
drinkers
that
mental
on
nicotine
helps
them
states
caffeine.
and
the
way
in
which
of
people
drugs
cocaine.
openly. Opium

and
and
perceive
their
surroundings.
These
drugs,
such
as
LSD,
ganga
mescaline
induce
dreams
going
changes
in
consciousness
that
users
compare
to
having
history.
168
and
social
or
into
trances.
These
experiences
can
be
frightening.
Module

Depressants
nervous
from
pain
pressure,
and
Drug
W
e
all
have
inhibitory
systems.
and
may
heart
opiates
These
induce
rate
and
(heroin,
effects
drugs
on
reduce
sleep.
They
breathing.
morphine
the
central
feelings
may
and
act
are
Applications
of
biology
peripheral
anxiety,
also
Examples
and
of
3
to
provide
lower
alcohol,
relief
blood
barbiturates
codeine).
abuse
use
benets
drugs;
that
they
are
therapeutic
part
of
drugs
our
have
everyday
on
experiences.
people’s
health.
Just
think
Moderate
of
use
the
Figure 4.1.1
Injecting heroin is at one
extreme of the drug-abuse spectrum.
of
Smoking a cigarette and drinking a cup of
non-therapeutic
drugs,
such
as
caffeine
and
alcohol,
often
has
little
impact
coffee are at the other extreme.
on
health.
However
,
palpitations
abuse
are
accepted
The
to
used
(mainly
of
because
alcoholic
both
misuse
feelings
misuse
of
to
is
inadequacy
they
liver
think
it
these
and
the
the
often
or
drugs
disease.
describe
alcohol)
drugs
of
The
use,
of
with
solve
drug
limited,
People
ranging
misuse
mental
turmoil.
them
effects
substances
however
associated
help
cause
terms
overuse
emotional
will
can
and
that
of
illegal
illness
often
emotional
or
are
or
from
drug
socially
substances.
with
take
drugs
behavioural
S tudy
problems,
though,
which
may
increased
may
lead
to
anxiety
be
symptomatic
mental
and
illness
depression.
of
such
Drug
mental
as
illness.
Misuse
drug-induced
misuse
is
as
of
schizophrenia,
much
foc us
drugs,
Drug dependence
a
problem
in
Alcohol,
nicotine
and
is
that faces Caribbean
Caribbean
countries
as
it
is
elsewhere
in
the
world.
trafcking from
ganga
are
viewed
by
many
young
people
as
a
rite
of
passage
peer
preference
–
wanting
to
t
in
with
a
social
group
–
a
driving
factor
.
The
fear
is
that
use
of
so -called
soft
drugs
may
use
of
hard
drugs
such
as
crack
cocaine
and
heroin.
effects
of
these
hard
drugs
often
results
in
users
becoming
and
Europe
to
is
should
of
consider
illegal
drugs
the
on
Experimental
society
use
Drug
lead
wider
onto
societies.
South America
is
another. You
often
problem
through
North America
adolescence;
one
hooked.
as
well
as
the
effects
on
Long-
individuals.
term
the
use
of
health
alcohol
and
and
wealth
nicotine,
of
nations
though,
than
brings
the
use
of
far
more
soft
and
problems
hard
for
drugs.
Drug dependence
Often
drug
it
users
effect
as
did
same
effect.
nd
when
that
they
after
rst
a
while,
took
it.
a
drug
They
does
increase
not
the
have
dose
the
to
same
regain
that
Link
may
be
two
This
happens
reasons
for
because
drug
tolerance
has
developed.
There
this:
Read

Metabolism
of
the
drug
has
increased
so
that
its
concentration
in
on
body

decreases
Neurones
drug
is
without
produce
needed
Eventually,
it:
quite
users
they
to
page
about
drug
dependence
175.
quickly.
more
receptors
occupy
come
are
more
the
to
them
rely
on
at
and
the
synapses
have
drug
the
and
so
that
same
feel
more
of
the
effect.
they
cannot
live
dependent.
Summary q uestions
1
Dene
the
terms
drug,
drug abuse,
drug tolerance
5
Read
about
drugs:
2
Suggest
term
3
Make
why
some
drug misuse
a
table
to
health
rather
show
medicinal drugs:
the
aspirin;
professionals
than
prefer
effects
of
nicotine;
alcohol
compare
the
are
statins;
legal
penicillin;
psychoactive
amphetamines;
and
effects.
barbiturates.
and
some
Discuss
are
why
Present
some
of
a
table
these
to
drugs
not.
Find
out
the
restrictions
on
sale
and
consumption
of
zidovudine
and
alcohol
in
several
countries
across
the
rituximab.
world.
4
the following
cocaine;
anti-histamines;
tobacco
(AZT);
of
heroin;
the
the following
paracetamol;
(epinephrine);
effects
drug abuse
6
adrenaline
the
marijuana;
Distinguish
between
stimulants,
depressants
of
and
Identify
these
the
pros
and
cons
of
restricting
the
sale
drugs.
hallucinogens.
7
Discuss
under
whether
all
drugs
should
be
legalised
and
sold
licence.
169
4.2
The
biological
The
Learning outcomes
completion
of
this
drug
we
call
of
alcohol
is
alcohol
actually
ethanol
(C
H
2
by
On
effects
section,
the
fermentation
absorbed
you
in
the
of
sugars.
stomach
as
it
When
ingested,
diffuses
readily
OH),
which
is
produced
5
it
is
usually
across
cell
rapidly
membranes.
–1
should
be
able
Ethanol
to:
is
a
good
metabolised

describe
how
alcohol

describe
the
in
the
cells
lining
vein
that
drains
short-term
the
liver
effects
and
the
energy,
the
providing
stomach,
but
.
29 kJ g
most
A
little
passes
is
into
directly
into
the
the
hepatic
liver
.
body
and
Metabolism of
long-term
of
is
portal
metabolised
in
source
of
alcohol
nervous
alcohol
on
system.
Alcohol
energy
is
absorbed
and
pathway
is
for
a
and
oxidised
precursor
alcohol
is
for
by
liver
cells.
synthesising
shown
in
Figure
It
fatty
is
used
acids.
as
The
a
source
of
metabolic
4.2.1.
Link
liver
Compare
the
metabolic
cell
CH
surface
CH
3
blood
OH
cytosol
2
pathway
membrane
with
what
you
know
about
CH
respiration.
See
pages
CH
3
20–29. You
OH
(ethanol)
2
NAD
could
draw
a ow
chart
to
show
an
ALD
outline
of
the
metabolic
pathways
of
reduced
NAD
NAD
respiration
and
include
the
one
reduced
shown
in
Figure
CH
NAD
CHO
(ethanal)
3
4.2.
1.
Key
ALDH1
ALD
alcohol
=
CH
(ethanol
COO
fatty
acids
3
dehydrogenase)
CHO
CH
3
ALDHI
ethanal
=
CH
acetyl
COO
3
dehydrogenase
ALDH2
coenzyme A
(acetate)
(cytosol)
ALDH2
ethanal
=
Krebs
cycle
dehydrogenase
(mitochondrion)
CO
+
H
2
Figure 4.2.1
Y
ou
S tudy
can
The
foc us
We
gain
most
metabolism
Triglycerides
fatty
acids,
acetate
of
our
of fat,
are
are
that
the
down
then
enter
split
the
As
quite
to
into
Krebs
that
Y
ou
to
a
a
large
just
a
few
NAD
in
of
fat
to
is
used
starts
This
more
to
The
a
If
hours,
accumulate
liver,
as
is
is
used
NAD.
of
to
someone
there
droplets
affects
those
little
it
in
oxidative
then
which
for
coenzyme
there
NAD
energy.
few
problem
the
as
through
reduced
provide
fatty
a
requires
recycled
occurs
over
to
is
of
be
this
alcohol
it
cells.
It
is
of
Instead,
liver
that
alcohol
mitochondria.
less
drinks.
of
needs
recall
quantity
fat.
cytoplasm
oxidation
of
should
result
oxidise
the
form
phosphorylation
A
TP
.
glucose.
broken
which
groups
energy from
not
see
cell.
mitochondrion
The metabolism of alcohol in the liver
reduced
each
O
2
who
generate
has
is
inside
a
need
the
people
drink
drunk
less
even
lot
after
over
a
cycle.
short
period
of
time
Long-term
Fatty
liver
drinking
is
a
–
so -called
effects of
short-term
bouts,
then
the
drinkers.
alcohol on the
effect
fat
binge
on
the
disappears
liver
.
and
If
a
the
liver
person
cells
has
days
recover
.
between
However
,
Did you know?
people
These
three
conditions
of
the
liver
liver
who
tissue
moderate
are
stages
of
alcoholic
liver
you
want
to nd
out
more
effects
of
alcohol
on
the
liver
a
good
search
term
to
or
stop
is
a
to
develop
reversible
completely.
In
the
hepatitis,
effect
into
cir rhosis,
in
which
brous
tissues
long
replace
isolate
liver
cells
now
in
begins
nodules,
to
which
degenerate.
do
not
get
Cirrhosis
is
if
in
which
people
term
the
sufcient
this
liver
blood
irreversible,
use.
will
170
drinking
likely
This
may
cells.
supply.
it
The
is
are
about
These
the
their
drinking
inamed.
disease.
develop
If
continue
becomes
not
get
worse
if
someone
decides
to
quit
drinking.
although
it
Module
The
functions
plasma
absorb
amino
accumulate
ow
into
a
cancer
liver
tissue.
and
also
of
body
has
drink
interactions
the
which
the
is
an
occurs
The
with
the
of
is
a
this
It
on
–
efcient
disorder
has
–
so
direct
for
in
myelin
in
the
loss
Blood
serving
the
blood
cancers
alcohol
system.
many
on
in
the
main
Figure
shows
2.2.
1
that
on
page
alcohol
factors
that
release
histamine.
is
144,
one
stimulates
of
which
the
mast
cells
to
and
on
sheaths
and
it
didn’t,
and
lives
it
make
Link
neurones,
the
effect
brain,
of
Myelin
and
of
the
by
the
neurones
reducing
long
sheaths
insulation
excitatory
effect
Over
If
people’s
inhibitions
the
insulators
biology
Link
See
V
omiting
by
of
to
fatal.
several
inhibits
the
have
prove
arteries
done
effects
It
behaviour
.
of
as
of
secrete
Applications
system
loosen
one
in
nervous
proteins.
neurone
are
factor
to
cells
T
oxins
bleeding.
damage
the
to
interactions
neurones
risk
the
cells
fewer
blood.
into
neurotransmitter
glutamate
maintenance
of
internal
fewer
and
may
ows
depressant,
channel
of
cirrhosis
a
of
the
nervous
effects
It
easier
.
of
speed
is
function
These
less
the
destruction
of
in
are
blood
from
much
result
consequences
them
reduces
Symptoms
a
inhibitory
effects
with
makes
Alcohol
as
it.
much
neurotransmitters.
This
and
There
the
toxins
resulting
social
activity
into
eventually
immediate
not
social
interferes
and
and
develop
important
inhibitions,
disrupted.
obstructed
cirrhosis.
an
enhances
are
albumin,
glucose
is
fulls
GABA,
as
alcohol on the
would
inuencing
liver
stomach,
may
Effects of
Alcohol
the
liver
symptom
liver
people
the
such
acids,
in
the
oesophagus
is
of
proteins,
3
term
Schwann
in
peripheral
it
and
cells.
demyelination
that
provide
around
PNS).
reminding
the
central
nervous
See
of
the
and
systems
page
about
the
some
120
if
(CNS
you
need
them.
transmission.
PNS
of
leads
sensory
to
polyneuropathy.
feeling,
particularly
in
the
Did you know?
hands
and
feet,
movement.
Alcohol
In
acts
numbness,
the
to
brain,
inhibit
tingling
neurones
the
release
and
may
of
a
reduction
be
ADH
affected
so
in
by
water
is
the
control
of
dehydration.
not
There
conserved
are
disorders
the
kidney.
Brain
cells
are
also
adversely
affected
by
the
low
oxygen
concentrations
of
the
blood
that
also
occur
in
people
who
alcohol-related
that
involve
degeneration
and
of
glucose
several
by
brain
tissues
and
gradual
loss
of
misuse
mental functions.
alcohol.
Alcohol
provides
nutrients
their
needs
balanced
of
as
in
well
for
diet.
alcohol
what
most
on
with
energy
This
the
are
known
alcoholic
with
means
liver
a
drink
that
and
deciencies
as
drinks.
that
these
nervous
of
‘empty
People
in
misuse
provides
people
system,
vitamins
calories’,
who
no
by
having
)
B
there
the
of
severe
severe
and
are
no
satisfy
constituents
compound
(especially
that
alcohol
a
effects
malnutrition
minerals.
1
Summary q uestions
1
Make
over
2
Explain
leads
3
why
the
the
cirrhosis
Describe
the
chart
periods
to fatty
Describe
b
4
a ow
long
the
show
the
effects
of
alcohol
consumption
on
the
liver
time.
short-term
consumption
of
a
large
quantity
of
alcohol
liver.
appearance
and
nervous
to
of
c
of
liver
tissue
in
people
who
have:
a
fatty
liver,
cancer.
short-term
and
long-term
effects
of
alcohol
consumption
on
system.
Figure 4.2.2
5
Summarise
6
Explain
why
such
vitamin
the
long-term
health
risks
of
excessive
alcohol
consumption.
Alcohol is a social lubricant,
but everyone should know their limits,
understand the effect the drug has on
as
someone
B
who
misuses
alcohol
may
have
deciency
diseases,
them and drink responsibly
deciency.
1
171
4.3
The
social
effects
Figure
Learning outcomes
A
On
completion
of
this
section,
unit
be
able
of
shows
alcohol
is
8
explain
the
describe
term
the

petty
describe
the
of
mass
alcohol
of
in
alcohol
a
variety
that
of
people
drinks.
metabolise
in
1
hour
.
of
alcohol
on
since
its
drinking.
the
rst
The
world
publication
British
issue
recommendations
in
Government’s
1987
as
shown
in
advice
the
has
about
been
updated
table.
behaviour, family
crime
the
throughout
unit of alcohol
effects
interpersonal
life,
is
units
to:
responsible

the
grams.
Governments

alcohol
you
This
should
4.3.1
of
and
effects
vandalism
of
alcohol
Date
Units of
alcohol
on
Men
Women
driving

describe
the
regulations
concerning
alcohol
and
in
driving
1987
21
units
different
countries.
1995
3–4
units
a
day
2012
3–4
units
a
day,
least
Some
4
safe
2
people
to
week.
In
people
not
extra
week
strong
2
the
1995
in
days
14
the
advice
drinking
how
with
the
equivalent
interpreted
know
but
abstinence
interpreted
drink
dangers
alcopop
a
units
a
week
consumption
these
many
units
a
day
at
2–3
units
a
day,
week
least
advice
of
given
21/14
was
these
a
2–3
changed
quantities
limits.
units
of
in
units
to
Often
alcohol
one
daily
to
mean
which
exceed
are
but
with
abstinence
drinking
limits.
day,
they
they
days
1987
in
every
2
that
it
these
how
was
each
there
are
many
limits
consuming.
week
session
However
,
is
at
a
as
The
they
do
advice
cider
lager
changed
again
taken
moderation,
liver
,
in
and
in
these
2012
can
to
has
get
include
some
short-term
worse
if
alcohol-free
effects
alcohol
is
on
the
drunk
days.
body,
every
Alcohol,
even
especially
if
the
day.
5
2.2
Limits
for
women
concentrations
the
same
are
in
lower
women
number
of
than
are
units
of
for
higher
men
than
alcohol.
because
in
There
men
are
blood
when
several
alcohol
they
both
reasons
drink
for
this,
1.4
including
tissue
cocktail
wine
spirit
their
has
a
smaller
limited
size
blood
and
greater
supply,
so
in
proportion
women
of
more
body
fat.
alcohol
Adipose
remains
in
alcohol
per
and
the
blood
rather
than
entering
other
tissues.
mixer
Figure 4.3.1
The units of alcohol in some
drinks
Blood
The
alcohol
blood
alcohol
concentration
concentration
(BAC)
is
measured
in
mg
of
3
of
100 cm
blood.
The
table
shows
the
effects
of
increasing
BAC
on
behaviour
.
S tudy
foc us
Social
On
page
129, we
dependence
the
as
Many
example of two of
categories of disease. Should
dependence on
as
included drug
an
alcohol
a disease? What
be
criteria
used to decide whether
should
alcohol dependent? After you
thought
answer Question
172
4d on
page
be
is
have
about these questions,
178.
people
dominate
alcohol
classied
someone
to
or
an
effects of
a
and
social
extent
live
with
them.
misuse
they
alcohol
Sadly,
it.
lubricant,
that
alcohol
it
It
as
there
is
not
just
becomes
can
think
part
are
of
of
their
people
an
else.
without
become
enjoyable
incorporated
little
lives
who
it
ever
dependent
accompaniment
into
their
way
of
coming
on
to
life
food
to
such
Module
Units of
alcohol
Blood
alcohol
Effects of
alcohol on
3
Applications
of
biology
behaviour
concentration/mg
Men
Women
–3
100
cm
blood
1½–3
½–2
20–50
reduced
tension,
3–5
2–3
50–80
euphoria,
5–8
3–5
80–120
slurred
8–15
5–10
120–260
loss
of
signs
16–26
10–15
>26
>15
Alcohol

dependence
their
general
are
may
in
colleagues
Petty

Acts
in
the
People
have
to
responsible
misuse
take
days
for
coordination,
condence
motor
walking
control,
in
a
loss of
staggered
inhibitions
way,
slow
of
voluntary
and
actions,
of
of
balance,
erratic
behaviour,
aggression
coordination, difculty
depression
loss
breathing
remaining
control
upright,
centres
in
the
extreme
brain,
confusion
death
following:
who
alcohol
off
work
absenteeism.
especially
loss of ne
in
if
often
as
a
Repeated
relationships
neglect
result.
with
absenteeism
work
damaged.
this
records
is
in
vandalism
show
because
escalate
implicated
of
and
behaviour:
occasionally
often
also
Police
Often
Aggressive
work:
dismissal,
are
crime:
crime.

from
involved
health
Hangovers
result
is
impaired
emotion
loss of
coma,
judgment,
increase
times
control
of
total
>400
Absenteeism

260–400
impaired
speech,
reaction
relaxed feeling,
that
alcohol
criminals
drink
Disagreements
into
aggressive
is
often
before
between
a
factor
drinkers
behaviour
in
committing
and
petty
crimes.
may
ghts.
Alcohol
is
homicides.
are
often
committed
by
people
who
are
drunk.
Summary q uestions
The
the
effects
of
inuence
alcohol
of
can
alcohol.
be
just
The
as
bad
when
withdrawal
not
drinking
symptoms
make
as
life
when
very
under
difcult,
1
not
only
for
the
drinker
,
but
for
his
or
her
immediate
family.
Explain
terms
symptoms
include
irritability,
shortness
of
temper
,
what
are
meant
by
the
These
shakiness,
unit of alcohol
and
daily
insomnia,
alcohol limits.
sweating,
nausea
persistent
and
shakes,
a
panic
high
attacks.
pulse
rate
At
their
and
very
even
worse,
there
frightening
are
visual
2
hallucinations.
This
condition
is
called
delirium
tremens.
One
way
Describe
the
effects
interpersonal
‘cure’
it
is
by
downward
arguments,
this
may
drinking
mental
more
and
aggression,
lead
to
alcohol.
physical
abuse,
family
Alcohol
spiral:
instability
breakdown,
dependence
neglect,
and
shortage
insecurity.
homelessness,
can
of
lead
to
poverty
the
3
and
long
term
The
annual
to the UK
destitution.
and driving
cost of
health
estimated
The
Alcohol
alcohol
on
behaviour.
a
money,
In
of
to
in
costs of
were
2008
crime
estimated
alcohol
misuse
services was
at
£2.7
billion.
and disorder
at over
£7
billion.
Effects on the workforce were
Alcohol
and
other
drugs
are
involved
in
many
road
accidents.
Alcohol
has
estimated
adverse
effects
on
people’s
concentration,
while
at
the
same
time
a
them
The
feel
more
legal
limit
for
someone
driving
in
the
USA,
UK
and
the
Explain
how
society
so
English-speaking
Caribbean
is
b
80 mg 100 cm
blood;
Explain
how
(as
in
most
of
Europe
and
the
non-English
speaking
Panama
and
Guadeloupe
and
drive
in
Cuba,
those
and
Martinique)
however
,
have
a
it
zero
is
50 mg 100 cm
tolerance.
It
is
.
are
Barbados,
illegal
to
blood
who
and
urine
to
costs
of
you
would
other
assess
drugs
misused
compared
that
with
countries.
suspect
someone
test
for
of
drink
alcohol.
In
driving
can
countries
take
where
samples
the
–3
80 mg 100 cm
cost
alcohol.
drink
4
Police
can
Caribbean
–3
including
alcohol
much.
in
the
France
billion.
in
–3
of
£6.4
condent.
maximum
much
at
making
of
legal
breath,
limit
is
Explain the thinking behind:
a daily alcohol limits, and
b safe limits for driving. In your
–3
blood,
the
limit
in
breath
is
35 µg 100 cm
and
in
urine
is
answers explain why the daily
–3
107 mg 100 cm
limits for women are lower than
The
of
penalties
licence
to
for
drink
driving
offences
can
be
very
severe,
including
loss
those for men.
drive.
173
4.4
The
effects
of
smoking
T
obacco
Learning outcomes
is
tabacam.
On
completion
should
be
able
of
this
section,
you
an
list
the
chemicals
to:
main
components
outline
that
the
the
effects
of
smoking
gaseous
outline
gaseous
tar
–
a
exchange
the
effects
of
smoking
tobacco
concentrations
T
obacco
combustion
substances
the
in
smoke
of
the
smoke
Nicotiana
nicotine
contains
products
tobacco
of
plant,
over
biological
that
that
4000
have
act
as
different
molecules
greatest
in
effect
exchange
and
cardiovascular
systems
are:
black
cardiovascular
distinguish
in
oily
as
containing
that
many
condense
aromatic
on
the
compounds;
lining
of
the
it
is
bronchi
nicotine
–
the
drug
in
tobacco,
which
is
the
reason
for
smoking
the
leaves
system
betwen
physical
carbon
monoxide
(CO)
–
a
highly
toxic
product
of
the
incomplete
and
combustion
psychological
liquid
droplets
on


high
of
system
dried
the
leaves
on


plant.
the
The
dried
contains
the
are
leaves.
breathed
the
plant
for
the
smoke


from
of
on
tobacco
The
insecticide
tobacco

made
of
compounds
in
the
leaves
dependence.

carcinogens,
smoke
When
It
(see
bronchi
settles
on
lead
the
vulnerable
the
to
smoke
trachea
into
lower
the
there
are
also
co -carcinogens
in
tobacco
135).
tobacco
down
that
benzpyrene;
page
inhaled,
travels
e.g.
the
sides
travels
which
lungs.
of
harmful
the
through
branches,
Much
of
bronchi.
effects
of
the
like
the
airways
an
particulate
This
is
into
inverted
the
part
Y
,
the
matter
of
lungs.
into
the
in
the
smoke
body
most
smoking.
Link
The
Find
videos
their
of
ciliated
coordinated
are fascinating
Remember
structures
by
cell
they
each
surface
to
see
movement. They
structures
that
–
cells
are
one
is
to
watch.
intracellular
surrounded
airways
ciliated
cells
mucous
these
to
the
an
and
throat,
to
that
effective
of
mucus
move
where
it
the
is
Short-term
Gaseous
T
ar
S tudy
is
an
part
you
distinguish
the
effects
on
these
gas
and
carcinogens
exchange
system;
this
the
mucus,
mucus
and
cells.
rather
or
like
onto
chemical
transmitted
the
Interspersed
Beneath
the
an
beat
the
in
escalator
,
otherwise
a
between
the
epithelium
surface.
defence
through
Cilia
the
against
air
.
are
T
ogether
,
dust,
Particles
stick
coordinated
up
the
airways
to
the
removed.
smoke
system
causing
inammation
monoxide
are
blood
and
affect
accumulates
is
cough
their
not
–
to
bronchi.
in
cells
the
and
of
the
epithelium
mucous
bronchi.
T
ar
glands
lining
also
secrete
the
tract.
inhibits
more
moved
upwards;
it
just
accumulates.
the
action
This
is
of
why
remove
The
the
accumulated
accumulated
mucus
mucus,
dust
provides
a
and
spores
suitable
nicotine
for
pathogens
to
grow.
There
is
plenty
of
food
and
it
is
absorbed
and
warm.
Smokers
are
often
more
susceptible
to
airborne
the
infections,
cardiovascular
goblet
affect
moist
into
are
swallowed
response
mucus
environment
carbon
that
cells.
two
from
and
more
mechanical
covering
exchange
which
so
smokers
systems. Tar
the
even
epithelium.
goblet
carefully
cilia,
between
ciliated
effects of tobacco
irritant,
of
mucus,
sure
a
foc us
As
Make
by
secrete
pathogens
layer
fashion
membrane.
lined
mucus-secreting
glands
form
spores
are
are
such
as
colds,
than
non-smokers.
system.
Cardiovascular
system
Carbon
diffuses
monoxide
irreversibly
with
into
haemoglobin
red
to
blood
form
cells
where
it
combines
carboxyhaemoglobin .
As
a
result,
Link
the
as
Nicotine
is
a
stimulant
168). The
sympathetic
system
part
is
nervous
of
system
the
(see
(see
much
autonomic
91).
Nicotine
the
blood
to
carry
oxygen
is
signicantly
reduced,
often
by
10%.
is
rapidly
seconds
of
nervous
system
glands.
174
as
of
page
nervous
page
capacity
As
absorbed,
inhaling.
a
and
result
It
acts
and
at
promoting
there
are
can
reach
synapses
the
the
secretion
increases
brain
stimulating
in
of
heart
in
the
less
adrenaline
rate
and
than
30
sympathetic
from
blood
adrenal
pressure.
Module
Nicotine
causing
also
the
capillaries.
to
cold
of
This
and
peripheral
stimulates
smooth
is
sympathetic
muscle
to
vasoconstriction,
during
exercise.
vascular
The
disease,
neurones
contract
and
which
can
innervate
blood
happens
long-term
which
that
reduce
effect
lead
to
of
ow
during
this
gangrene
may
Applications
of
biology
arterioles,
to
our
and
3
response
be
amputation
limbs.
Smoking
also
composed
therefore
factors
causes
red
more
than
chances
of
coronary
people
of
an
blood
difcult
promote
a
blood
arteries.
already
at
increase
cells.
to
pump.
blood
clot
the
heightens
of
blood
Platelets
clotting.
because
relative
makes
(thrombus)
This
risk
in
This
are
These
the
risk
of
effects
in
(see
the
to
and
release
the
particularly
heart
page
blood
viscous
increase
arteries,
coronary
factors
of
more
stimulated
two
occurring
other
proportion
become
disease
in
160).
Figure 4.4.1
Even the rst cigarette has
Passive smoking
harmful effects on health; more dangerous
T
obacco
smoke
not
only
has
effects
on
the
smoker
,
it
also
has
effects
on
is the power of nicotine to become
addictive
other
with
people,
a
smoke
smokers
smoker
.
which
burning
tip
and
Smoke
comes
which
from
from
is
non-smokers
a
burning
the
called
lter
alike,
who
cigarette
or
mouth
‘sidestream’
are
in
consists
end
smoke.
and
the
of
same
mainstream
smoke
About
room
85%
from
of
the
Link
the
smoke
Collect
from
of
a
burning
tobacco
cigarette
smoke
mainstream
are
smoke.
in
is
a
sidestream
higher
Breathing
smoke.
Many
concentration
in
cigarette
in
smoke
of
the
sidestream
like
this
some
is
than
help
in
give
passive
of
smoking.
people
you
who
conditions
live
as
second-hand
or
work
smokers.
smoke
in
with
smokers
Children
their
are
homes.
develop
the
particularly
Their
same
at
lungs
risk
quit
published
to
smoking. These
information
nicotine
difcult
People
leaets
components
it
addiction
is
to
about
and
will
aspects
how
overcome.
medical
from
develop
breathing
more
slowly
and
Summary q uestions
they
are
at
children,
increased
33%
of
risk
male
of
asthma.
non-smokers,
Researchers
and
35%
of
estimated
female
that
40%
of
non-smokers
1
were
exposed
to
second-hand
smoke
globally
in
2004.
This
exposure
Make
a ow
effects
estimated
to
have
caused
deaths
from
asthma
and
heart
and
of
This
represented
about
1%
of
deaths
the
to
show
the
components
of
lung
tobacco
diseases.
chart
was
smoke
on
the
gaseous
worldwide.
exchange
and
cardiovascular
systems.
Drug dependence
2
As
we
saw
on
page
169,
drug
users
can
develop
tolerance.
Nicotine
Explain
in
at
cholinergic
exposure
metabolism
taking
a
synapses
neurones
and
drug
by
make
leads
because
to
it
interacting
more
of
physical
has
with
these
receptors.
receptors.
dependence .
become
part
of
With
This
Drug
their
is
are
not
using
their
drug,
they
often
users
change
need
metabolism.
experience
which
only
stop
when
the
user
takes
physical
the
drug
of
the following
the
healthy functions
gaseous
exchange
of
the
mucous
glands
system:
cilia,
to
to
keep
When
and
goblet
cells.
drug
Describe
the
effect
of
carbon
withdrawal
monoxide
symptoms,
roles
continued
a
3
users
the
acts
again.
on
the
transport
of
This
oxygen.
keeps
drug
headaches,
sweating,
users
‘hooked’.
stomach
gain
in
The
pains,
weight,
withdrawal
craving
for
increased
a
symptoms
smoke,
appetite,
for
anxiety,
irritability
nicotine
are:
4
tiredness,
and
insomnia.
Outline
of
the
the
risks
to
the
cardiovascular
health
system
of
smoking.
Psychological
drug.
In
this
there
are
rituals
dependence.
are
dependence
form
of
is
most
both
a
behavioural
dependence,
surrounding
For
elements
of
the
people
forms
drug
who
of
change
drug-taking
are
taking
has
that
dependent,
dependence.
A
–
a
craving
become
a
reinforce
it
is
gradual
for
habit;
the
often
5
the
likely
that
reduction
in
there
the
Smoking
is
WHO
be
disease.
a
drug
may
reduce
physical
problems,
then
dependence,
it
may
be
but
hard
if
to
there
‘kick
are
the
are
addicted
dependence,
such
as
to
nicotine
withdrawal
wanting
a
show
physical
symptoms
smoke
at
certain
and
and
of
the
what
is
disease
meant
and
by
justify
underlying
habit’.
decision
by WHO
to
call
People
a
disease.
psychological
compulsive
times
by
self-inicted
Explain
smoking
who
a
self-inicted
the
psychological
considered
use
a
of
to
day.
patterns
of
behaviour
,
6
Dene
the
smoking,
terms
passive
physical dependence,
psychological dependence.
175
4.5
Chronic
smoking-related
There
Learning outcomes
are
On
completion
should

be
state

able
the
of
this
you
many
related
diseases
explain
what
is
smoking-
meant
by
pulmonary
diseases
concentrating
obstructive
conditions
to:
chronic
obstructive
section,
are
on
occur

chronic

emphysema
are
long-term,
pulmonary
that
that
diseases
disease
in
the
related
or
to
smoking.
chronic,
(COPD)
bronchi
is
and
diseases
a
In
of
collective
lungs,
this
the
section,
lungs.
term
used
we
Chronic
for
including:
bronchitis
chronic
disease
COPD
(COPD)
COPD

describe
the

the
effects
of COPD
is
a
signicant
cause
of
ill
health;
globally
the
death
rate
from
this
on
condition
is
on
the
epidemic,
since
increase
and
this
is
linked
with
the
smoking
lungs
explain
how
lung
smoking
is
the
major
cause.
Asthma
of
bronchi
is
another
.
cancer
Bronchitis
is
the
inammation
the
and
other
air
passages.
The
develops.
rst
sign
of
mornings,
mucus
to
As
all
air
the
may
to
disease
of
only
be
day.
capable
and
Chronic
bronchitis
and
the
the
cold
or
person
Emphysema
walls
feet,
of
the
elasticity
is
often
a
die
disease
(the
break
a
by
leads
in
down,
it.
The
only
the
extra
becomes
protective
that
way
in
causes
gradually
means
the
wheezing
steps
and
and
is
the
the
more
epithelial
mucus
person
the
lips
can
clear
the
the
the
occur
at
person
may
may
include
appear
affected
become
blue.
person
seriously
acute,
infection.
structure
spaces
producing
If
skin
a
totally
symptoms
and
may
advanced,
becoming
Other
emphysema.
of
breathlessness
well
before
bronchitis
result
air
disease
few
which
tiny
This
coughing.
to
the
a
severe
inammation
bronchi
lining
and
the
failure,
as
particularly
coughing.
time
inuenza,
alveoli
and
heart
may
tissue.
coughing,
taking
the
cilia
lungs,
by
The
of
the
scar
is
the
of
of
incapacitated
of
a
By
lining
the
mucus
swelling
catches
by
in
usually
sputum.
loss
worsens,
the
cough,
up
replaced
of
a
The
the
accumulates
breathless
Figure 4.5.1
brings
leading
passages
times
is
produced.
becomes
produced
the
disease
which
be
damaged,
tissue
the
in
the
larger
of
the
lungs)
air
lungs
changes.
gradually
spaces.
This
lose
The
their
means
that
Withdrawal symptoms and
the
lung
has
a
smaller
surface
area
for
gas
exchange.
As
a
result,
the
cravings make nicotine addiction one of
the hardest to give up; this is why it is
much better not to start in the rst place
affected
person
oxygen.
Blood
damage
to
lung
turn
the
in
As
result
the
of
to
breathe
protein
alveoli
Elastase
hard for
as
breaks
people
out.
responsible for
right
of
this,
the
more
lungs
ventricle
of
the
blood
uid
heart.
vessels
narrowed
side
of
enlarges,
from
builds
often
the
right
ventricle
frequently
become
blood
become
for
bringing
it
you
breathe
down,
with
making
emphysema
irritates
chemicals
secreted
that
are
that
by
the
up
leads
radicals
these
in
for
macrophages
attract
capable
responsible
which
176
the
in
to
As
the
the
carry
heart
to
to
and
to
tissues,
failure
to
right
side
page
lead
blood
of
the
the
to
and
lungs
changes
neutrophils
of
the
smoke
normally
in
the
neutrophils.
digesting
damage
damage
protects
and
lung
seen
the
alveoli,
Proteases,
to
rise
heart.
legs
and
161).
macrophages.
tissue
in
and
from
in
turn
Proteases
these
emphysema.
enzyme
alveoli
which
particularly
inhibitor
,
proteases.
chemicals
Oxidants
release
elastase,
are
are
enzymes
are
and
for
in
through
pressure
particularly
(see
the
These
the
sufcient
can
progresses
pump
causes
the
gain
this
blood
destroyed.
which
heart
order
emphysema
that
or
body
in
damaged,
foc us
the
recoil
out.
it
is
harder
Emphysema
Smoking
Elastin
it
The
veins
ankles.
S tudy
right
breathe
in
deteriorates,
make
the
to
replenishment
lungs.
a
the
tissue
oxygen
has
vessels
free
alpha-1-antitrypsin,
Module
3
Applications
carcinogens
in
and
in
biology
co-carcinogens
tobacco
mutations
of
smoke
epithelial
cells
of
the
bronchi
regulation
is
uncontrolled
a
of
the
cell
cell
division
by
mitosis
b
Figure 4.5.2
a Drawing of a part of a lung from someone with emphysema. b
A healthy
primary
lung drawn to the same scale for comparison.
cancer
Almost
all
tumour
bronchus
tumour
Lung
–
of
lung
cancer
are
related
to
smoking.
In
addition
in
the
lung
cancer
,
smoking
is
also
a
contributory
factor
to
break
the
off
blood
such
as
cancer
of
the
in
carcinogens
bronchial
and
genes
co -carcinogens
epithelial
genes
code
that
cells,
for
unchecked.
If
control
causing
the
inhibitory
a
mutated
cell
in
tobacco
smoke
mutations.
cycle
proteins.
cell
and
and
spread
lymph
secondary
in
tumours
in
mouth.
Cells
interact
become
with
e.g.
DNA
and
Once
survives
mitosis
lost,
and
mutate.
cells
evades
liver
continue
e.g.
tissue,
lymph
nodes
cancerous
Some
to
destruction
lymphoid
organs,
Figure 4.5.3
the
the
to
other
The
of
carcinoma
other
tumours
cancers,
wall
bronchial
cells
through
cases
a
secondary
promoting
if
cycle
disrupted
of
these
The development of a
tumour in the lungs
divide
by
Did you know?
lymphocytes,
bronchial
then
it
can
epithelium.
grow
Blood
into
a
vessels
mass
and
of
cells,
lymph
or
tumour
,
vessels
grow
within
into
the
the
Scientists
tumour
,
supplying
it
with
oxygen
and
nutrients
so
that
the
cells
spent
unravelling
continue
may
and
to
take
be
divide.
20–30
Although
years
for
a
this
is
tumour
uncontrolled
to
be
large
growth,
enough
to
it
is
not
cause
fast.
the
will
tumour
,
obstruct
a
and
up
or
bronchial
airways
blood,
primary
and/or
occurred,
it
link
between
and
lung
cancer.
involved
epidemiology
Research
problems
and
will
carcinoma,
blood
suggest
vessels.
lung
grows
within
Symptoms
cancer
as
the
in
the
a
lung
tissue
smoker
,
diagnosis.
If
it
such
the
as
on
on
page
tumour
will
be
treated
there
more
by
(see
the
ow
chart),
will
chemotherapy
be
secondary
difcult
to
treat
and
then
it
may
radiotherapy.
be
tumours
in
other
If
parts
178)
and
animals. To nd
about
the
(see Question
work
of
laboratory
out
more,
Richard
work
read
Doll
and
cancer
removed
Peto
in
the UK,
and Oscar
by
Auerbach
surgery
has
the
smoking
Richard
still
time
detected.
coughing
is
long
It
2
As
a
can
in
the USA.
metastasis
of
the
body
successfully.
Summary q uestions
1
State
2
Describe
the
chronic
the
diseases
differences
associated
between
the
with
smoking.
bronchus
of
a
non-smoker
and
a
smoker.
3
Outline
4
Describe
5
State
how
emphysema
what
the
happens
symptoms
of
develops.
in
the
lung
development
cancer
and
of
lung
explain
the
cancer.
advantage
of
early
Figure 4.5.4
The message is loud and
clear – eat a balanced diet, take regular
diagnosis.
aerobic exercise and follow sensible advice
6
Outline
7
Discuss
the
consequences
of failure
to
seek
treatment for
lung
cancer.
about smoking, alcohol and other drugs.
But are you listening? How effective are
the
success
of
anti-smoking
measures.
health promotion agencies at getting their
message across?
177
4.6
Practice
exam-style
Substance
Answers to
Most
of
some
1
these
are
more
all
exam-style questions
questions
about
closely
Chronic
other
the
are
about
topics
questions
bronchitis
is
a
in
in
can
abuse
be found on the
substance
Module
Paper
3
to
abuse,
accompanying CD.
but
a
represent
by the age of 70 in each of the different groups.
associated
b
with
Suggest
groups
smoking.
a
Using the information in Figure 4.6.
1, state the
percentage of male British doctors who had died
2.
condition
questions:
i
Explain
the
meaning
ii
State THREE symptoms of chronic bronchitis.[3]
iii
Smoking-related
categorised
as
of
the
diseases
social
term
are
diseases
chronic.
c
[1]
diseases.
Explain
at
the
Molecular
cancer.
as
have
Project
stating
disease,
with
developed
that
Immunology Centre
but
it
does
advanced
production
of
uncontrolled
b
Outline
c
i
how
Explain
d
a
Explain
how
lung
why
people
read
cancer
cancer
such
the
only
as
c
Discuss
the
that
a
that
[5]
polio.
of
b
[2]
arise
the
With
light
The
study
sample
those
of
who
had
never
recorded. The
each
who
are
smoking
started
into
three
those
were
group
after
of
was
smoked,
times
results
effects
divided
those
of
different
the
doctors
were
and
percentage
at
on
male
doctors
smokers
alive
the
liver.
effects
of
[5]
alcohol
on
the
[5]
social
that
consequences
may
arise from
of
the violent
alcohol
abuse.
[5]
reference
to
alcohol,
between
explain
physical
and
the
psychological
is
[3]
What
meant
by
a
unit
of
alcohol?
[2]
ii
Explain the advantages of recommending daily
c
Comment
on
the fact
that
some
[2]
tolerance for
drink
countries
have
driving.
a
[3]
[3]
long-term
1951. The
in
the
passage
d
large
and
alcohol limits and safe limits for driving.
if
above.
A
large
i
zero
2
of
immediate
dependence.
[2]
might
sentence
to
system.
the
difference
cannot
and
changes
briey
behaviour
differs from vaccines
measles
consumption
leads
cause
developing.
the rst
Describe
nervous
patients
develops.
problems
b
the
of
4
the vaccine
regular
alcohol
reported
stimulates
proteins
the Cuban vaccine
lung
how
on
is
condition
against
the
of
in
proliferation.
diseases
Comment
the
[2]
lung
prevent
cancer. The vaccine
cell
prevent
for
improve
antibodies
Suggest
ii
against
cannot
[2]
[2]
director Gisela Gonzalez
the vaccine
[3]
different
smoking causes death from lung diseases.
why.
a vaccine
the
Explain why the evidence from the British Doctors
long-term
Havana
amongst
doctors varied.
quantities
Scientists
rates
self3
inicted
of
death
Study, as shown in the graph, does not prove that
sometimes
and
why
of
the
shown
who
heavy
doctors
study
in
in
a
regarded
5
as
a
were
a
Explain
b
State THREE
with
smokers.
who
whether
alcohol
dependence
should
be
disease.
[5]
in
categories:
began
Figure
on
Britain
Discuss
who
were
was
c
4.6.
1.
the
meaning
cirrhosis
does
Explain
services
not
or
in
of
the
which
differs from
misuse
whether
dependence
120
ways
you
should
whether
term
the
the
drug abuse.
liver
liver
of
of
a
a
[3]
person
person
alcohol.
think
be
[2]
people
treated
people
by
with
alcohol
national
should nd
health
their
own
elam
treatment.
100
In
2006,
the
[3]
British Virgin
Islands
joined
many
other
fo
fo
egatnecrep
srotcod
hcae
evila
puorg
countries
80
smoking
d
and
in
Explain
territories
public
the
in
the Caribbean
in
banning
places.
reasons for
banning
smoking
in
public
60
places.
6
40
a
[5]
Describe
gaseous
never
the
short-term
exchange
effects
system
of
tar
(trachea,
on
the
bronchi
and
smoked
lungs).
20
light
[4]
smoker
heavy
smoker
b
Explain
how
chronic
bronchitis.
smoking
can
lead
to
emphysema
and
0
40
50
60
70
age/years
Figure 4.6.1
178
80
90
[6]
100
c
Describe THREE
system.
effects
of
smoking
on
the
blood
[5]
Module
7
Tobacco
smoke
benzpyrene,
potent
a
contains
and
cancer-causing
State
FOUR
carcinogens,
such
co-carcinogens. Together
other
as
these
are
e
agents.
carcinogens.
include
this form
each
your
of
Suggest
the
[4]
of
3
Applications
anaemia
and
of
give
biology
a
reason for
choices.
how
health
prevalence
of
[4]
authorities
could
iron-deciency
monitor
anaemia
in
the
Caribbean.
b
Outline
the
stages
in
the
development
of
cancer.
[5]
9
c
Explain
of
the
them,
why
it
is
important
symptoms
especially
of
if
cancer
they
that
and
people
do
not
are
aware
with
ignore
smoke.
A variety
is
[3]
Figure
4.6.2
shows
global
mortality for
the
of
heavy
alcohol
risk factors for
disease
in
which
misuse
Explain
in
what
a
are
the
serious
good
most
indicator
of
associated
the
of
these
level
of
populations.
information
collect
to nd
out
about
the
cirrhosis
level
of
you
misuse
of
2004.
alcohol
high
is
disorders
of
eight
would
leading
alcohol-related
drinking. One
cirrhosis,
a
8
[3]
lung
in
a
country.
[5]
blood
b
Outline
c
Explain
the
social
harm
done
by
alcohol.
[5]
pressure
tobacco
higher
use
with
high
why
than
the
economic
simply
the
alcohol-related
costs
costs
of
diseases
of
alcohol
treating
like
are far
people
cirrhosis.
[5]
blood
10
glucose
a
Explain,
using
classied
as
examples,
why
self-inicted
some
diseases
are
diseases.
[3]
physical
b
inactivity
Discuss
related
why
named
diseases
alcohol-related
should
be
and
classied
in
smoking-
several
overweight
and
different
obesity
c
high
cholesterol
HIV/AIDS
and
of
dengue fever
ii
Compare
d
8
0
0
0
6
7
0
0
0
0
0
0
4
5
0
0
0
0
(total:
in
0
0
3
0
0
1
2
0
0
0
0
0
0
0
0
mortality
the
ways
Explain
million)
effect
two
what
is
meant
by
the
term
11
of
Although
information
in
Figure
4.6.2
to
which
HIV
and
the
transmitted.
is
a
[2]
long-term
disease,
leading
causes
of
ill
health
and
the
world
sketch
graph
to
in
infectious
show
programme
given
concentration
and
legal
are
controls
3
of
the
consisting
months
the
on
apart
of
on
the
blood.
the
measures
should
health
and
that
[4]
consumption
of
take
early
anaemia
to
reduce
the
in
death.
poor
are
these
illegal.
some
drugs
are
considered
legal
and
is
the
the
most
world
and
health
of
illegal.
[3]
smoke
contains
Both
are
nicotine
absorbed
by
and
the
carbon
blood.
[5]
Describe THREE
is
women
short-term
effects
of
nicotine
on
common
a
major
and
body.
[3]
risk
c
the
the Caribbean,
cocaine
burden
the
disease
and
health
b
Iron-deciency
throughout
Heroin
why
as
monoxide.
ill
alcohol
drugs.
Explain
Tobacco
in
a
many
the formation
[5]
preventative
authorities
deciency
available for
stimulate
of vaccine
there
others
of
[2]
mortality
a
across
the
not.
discuss:
are
factor
by
[1]
the
the
Draw
is
a vaccination
doses
tobacco
ii
caused
risk factor for
disease.
i
in
are
HIV/AIDS
are vaccines
antibodies.
thousands
58.5
There
antibody
Explain
Use
why
dengue fever
diseases. Vaccines
Figure 4.6.2
b
both
use
but
a
are
[6]
sex
dengue fever virus
alcohol
disease.
viruses.
i
unsafe
categories
Describe
the
effects
of
carbon
monoxide
on
the
children.
body.
Health
the
by
authorities
pregnant
the
half
of
women
disease
all
estimate
and
in
that
maternal
that
up
to
the Caribbean
it
is
a factor
in
one-half
are
as
d
affected
many
The
term
who
as
Discuss
the
being very
d
reasons for
iron-deciency
State TWO
anaemia
other
[3]
is
a
categories
deciency
of
disease
large
heavy
is
often
quantities
smoking
of
applied
alcohol.
should
be
to
people
Discuss
classied
as
abuse.
[5]
anaemia
common.
Iron-deciency
alcohol abuse
drink
whether
deaths.
drug
c
[3]
of
disease.
that
could
e
Explain
the
term
f
Explain
the
likely
children
and
passive smoking.
effects
teenagers.
of
tobacco
[2]
smoke
on
[3]
179
Glossary
altruism
any
action
which
an
atherosclerosis
process
in
which fatty
A
individual
abiotic factor
chemical
any
physical
another,
or
environmental factor
inuences
absorption
a
that
e.g.
another’s
graph
an
that
in
performs for
defence
material
and feeding
young
amination
community
spectrum
organism
group
which
(–NH
)
introduces
to
systole
pump
contraction
blood
autonomic
into
within
the
wall
of
artery
atrial
reaction
amine
an
develops
into
nervous
the
of
the
atria
ventricles
system
2
shows
the
absorption
wavelengths
such
as
of
light
by
another,
different
a
acids
pigment,
cholinergic
neurotransmitter;
produced
transfer
in
the
Krebs
ammonia
of
compound
link
2-carbon
from
formation
keto
acids;
of
involuntary
amino
reaction
comprising
see
acetyl
groups
does
to
decomposers
excess
respiration
not
anterior
cycle
production
deaminating
anaerobic
to
by
motor
require
pituitary
autotroph
of
as
a
amino
result
acids
respiration
carbon
it
needs
compounds from
potential
reverse
in
potential
pituitary
that
secretes
across
a
cell
membrane
of
TSH,
LH,
part
nerve
cell
(or
a
muscle
carbon
hormones,
action
–70 mV
to
spectrum
activity
of
a
about
compound
graph
process,
microorganism
+30 mV
that
such
shows
the
synthetically)
growth
as
produced
by
diet
that
sufcient for
at
of
antibody
different
(or
to
nutrients, bre
wavelengths
of
following
plasma
light
immunity
immunity
contact
with
an
antigen
by
or
inhibit
species
present
genetic
diversity
infection
or
cells
to
that
is
secreted
the
with
rapid
onset
(active
the
B-cells)
presence
different
these
short
duration,
e.g.
(ADH)
species
and
fever
biological
pyramid
displays
numbers
made
in
the
released from
pituitary
antigen
nucleotide
that
organisms,
or
energy
at
their
different
levels
in
an
ecosystem
any factor
that
inuences
hypothalamus
the
involving
organisms,
posterior
such
phosphorylated
method
of
by
as
predation
and
competition
gland
blood
(ATP)
in
are found
an
communities
adenosine triphosphate
species
ecosystems
hormone
octapeptide
neurones
dengue
the
each
in
of
biotic factor
and/or
area,
by
trophic
disease
an
within
antigen
antidiuretic
vaccination
in
the
biomass
acute disease
water
(biodiversity)
bacteria
protein
response
gained
and
and
produced
kill
which
active
provides
needs
a
and
photosynthesis,
dioxide
e.g.
biological diversity
about
the
organic
FSH
antibiotic
cell) from
make
of
specic
a
systems
obtains
B
front
energy
difference
that
that
balanced diet
action
to
system
and
nervous
organism
oxygen
gland
nervous
sympathetic
parasympathetic
ammonication
see
synapse
acetyl-coenzyme A
e.g.
deamination
chlorophyll
acetylcholine
the
of
any
macromolecule,
pressure
force
acting
on
blood
e.g.
vessels
with
ribose
as
the
pentose
polysaccharide
sugar;
or
protein,
that
B-lymphocyte
universal
energy
currency
in
stimulates
cells
the formation
that
adhesion
force
of
attraction
between
type
responds
to
molecules
and
cellulose
antigen
cell
presentation
display
by
hydrogen
antigens
bonding
within
MHC
proteins
hormone
secreted
by
the
and
class
glands;
works
with
antitoxin
the
antibody
mass
nervous
type
neutralises
system
index
of
antibody
relative
toxic
exercise
any
exercise
in
which
produced
by
pathogens,
e.g.
the
gaseous
exchange
system
and
by
that
molecules
indicator
that
to
of
body
height
capsule
in
cup-shaped
cause
tetanus
kidney
nephron
that
by
surrounds
bacteria
cell
substances
structure
aerobic
antigen
plasma
that
Bowman’s
sympathetic
a
II)
mass
adrenal
into
(class I
body
adrenaline
lymphocyte
specic
of
secretes
walls
a
antibodies
differentiating
water
of
of
a
glomerulus
to
collect
and
ltrate
heart
supply
oxygen
aerobic tness
efciency
a
with
to
muscle
measure
which
gaseous
exchange
muscles
with
of
the
diphtheria
apoplast
the
heart
system
tissue
and
and
supply
all
the
tissue; forms
other
a
cell
walls
in
a
pathway for
substances
plant
C
water
travelling
Calvin
through
oxygen
plant
cycle
see
light-independent
tissues
stage
aerobic
respiration
respiration
arteriole
that
type
of
blood
vessel
between
cancer
requires
artery
oxygen
and
capillary;
disease
growth
AIDS
Acquired
of
Immunodeciency
blood
through
that
involves
the
determines ow
capillaries
of
a
malignant
tumour
in
the
by
body
Syndrome;
collection
widening
of
(vasodilation)
or
capillarity
opportunistic
infections
related
constricting
to
thin
HIV
articial
infection
immunity
immunity
spaces
rule
neurones
by
are
vaccination
or
by
against
of
the
water
pull
in
of
gained
gravity
all-or-nothing
movement
(vasoconstriction)
injection
due
to
adhesion
and
surface
of
tension
either
stimulated
to
send
impulses
or
antibodies
carbaminohaemoglobin
not;
they
do
not
have
graded
atheroma
fatty
tissue
within
the
formed
responses
to
stimulation
of
an
when
carbon
dioxide
artery
combines
180
compound
wall
with
haemoglobin
Glossary
carbon xation
dioxide
into
incorporating
a
more
carbon
clonal
carbon
of
complex
T-cells)
compound
carboxyhaemoglobin
formed
when
combines
cells
compound
carbon
clonal
monoxide
irreversibly
of
to
carbon
a
by
and
increase
lymphocytes
mitosis
selection
addition
compound,
dioxide
in
of
carbon
e.g. xation
photosynthesis
in
MHC
closed
class
and
active
have
to
of
ow
break
down
simple
bacteria
organic
inorganic
dioxide
demyelination
cell
receptors
antigen
e.g.
decomposers
carbon
presented
from
compounds
and
loss
myelinated
associated
with
and fungi
that
compounds
to
such
as
ammonia
of
myelin
sheaths
neurones;
drinking
alcohol
in
excess
proteins
II
vessels,
number
produce
selection
circulation
within
in
(B-cells
cells
that
complementary
the
to
memory
lymphocytes
with
haemoglobin
carboxylation
dioxide
expansion
selected
of
denitrication
blood
arteries
and
veins
ions
to
conversion
nitrogen
gas
(N
of
nitrate
)
2
carcinogen
cancer,
e.g.
ionising
cardiac
cardiac
agent
certain
the
the
causes
chemicals
heart
done
pumping
and
during
the
by
blood
and
one
ratio
the
consumed
that
immune
are
left
the
by
response
activated
in
beat
between
ventricle
volume
cardiac
protons
across
a
host
active
with
of
organism
simple
that
type
cells
an
uses
chemical
and
the
diffusion
autotrophic
to x
the
competitive
between
species
(outer
stroma
gains
its
inner)
grana
that
of
immune
that
in
any
chloroplasts
compound
that
absorbs
light
synapse
acetylcholine
released
by
is
the
neurotransmitter
long-term
inammation
associated
with
chronic disease
where
pre-synaptic
bronchitis
involving
synapse
the
of
same
live
in
(of
the
all
species
results
each
in
when
one
ecological
to
of
the
proteins
infection;
protein C3
any
has
a
central
producers
organism
and/or
other
atheroma
to
in
heart
one
or
restriction
muscle
more
of
by
muscle
that
ADP
make ATP
to
(plural
and ATP
transfers
cristae)
large
infolding
synthase
area for
stems
involve
photolysis
cytosol
the
surrounds
of
have
part of the
all
the
phase
on
in
insulin
of
the
heart,
ventricles ll
with
owering
two
leaves
of owers
plant
cotyledons;
with
are
in
net-like
4s
or
5s,
3s
disease
disorder
or
illness,
poor functioning
body
double
or
associated
part
during
circulation
travels
in
of
of
the
mind
circulation
blood
drug
with
broad
of
through
one
the
the
body,
heart
twice
mammals
any
substance
that
in
taken
inuences
the
abuse
body
use
effect
that
is
illegal
drug;
of
a
not
a
or
the
that
mind
legal
called
see
and
into
process
drug
intended;
often
dependence
covering
leaves
that
water
reduced
surface
act
effects
plant
drug dependence
ETC
then
to
use
drug
gain
of
an
misuse
physical
psychological
dependence
layer
and
disease
slow
of
enzymes
photophosphorylation
of
to
to
reduction
its
and
seed
parts
occurs
membrane;
non-cellular waxy
production
a
veins;
drug
in
phosphate
surface
epidermis of
cyclic
compound
mitochondrial
provides
the
has
body
phosphate
by
to
atria
many
e.g.
coronary
large
and
and
non-infectious
relaxation
the
complete
heart disease
with
dead
it
blood
not
heterotrophic
on
caused
eats
shreds
decomposers
dicotyledonous
non-specic
comprising
photophosphorylation
bronchi;
with
part
system
material,
resistance
diastole
competition
that
or
that
mellitus
disease
same
animal
material
area for
time
neurone
smoking
disease
egests
with
cuticle
cholinergic
by
water
organisms
that
exclusion
respond
inner
pigment
xylem
between
role
crista
chloroplasts
chloroplast
the
decaying
arteries
two
and
the
occupying
coronary
but from
and
is
that
creatine
envelope
membranes
surround
that
light
detritivore
consumers
reactions
chloroplast
chronic
at
all
levels)
that feeds
energy from
organism
not from
chemical
found
trophic
blood ow
chemotroph
water
diabetes
community
consumer
reactions
through
attraction
complement
gradient
carbon
energy
of
complement
of
of ATP
chemoautotroph
force
area
muscle
transport
electrochemical
synthesis
transpiration
in
niche
membrane
subsequent facilitated
their
in
in which T-cells
enter
the
by
tension
molecules
response to
pathogens that
chemiosmosis
down
caused
occur
cell-mediated immune response
of
cohesion–tension
transmitted
changes
efciency
work
oxygen
that
radiation
cycle
within
the
any
body’s
type
does
drug tolerance
of
not
or
quantities
same
that
are
becomes
so
that
required
to
part
of
larger
gain
the
effect
ductless
NADP
drug
metabolism
gland
secretes
gland
without
directly
into
a
the
duct
blood
cytoplasm that
organelles
E
onset
and/or
circulatory
body
in
long
duration
system
which
substances
system
a uid
around
cytotoxic T-lymphocyte
of
the
that
kills
infected
host
type
of T-cell
cells
ecological
transports
the
efciency
consumed
body
trophic
by
level
the
as
a
the
energy
organisms
in
percentage
one
of
the
D
cirrhosis
there
is
disease
of
growth
of brous
associated
with
the
liver
drinking
in
which
tissue;
alcohol
energy
deamination
in
acid
to
breakdown
remove
amine
of
the
previous
trophic
level
amino
group
entering
(–NH
)
ecological
niche
the
role
of
a
species
2
excess
to form
climacteric
steep
increase
respiration
rate
ripening
some fruit,
of
in
associated
e.g.
with
bananas
a
keto
acid
decarboxylation
carbon
dioxide
compound
and
ammonia
reaction
is
in
which
removed from
a
in
a
community
in
the food
with
other
including
chain
and
species
its
position
interactions
and
the
physical
environment
181
Glossary
ecosystem
a
community
features
self-contained
named
and
trophic
that
interactions
effector
out
or
ion
it
food
that
by
web
of
or
two
or
heterotroph
more
point
in
the
energy ow
diagram
that
shows
chains
in
many
gradient for
compound
across
G
a
glial
composed
cell
cell
gradient
the
nervous
and
protects
neurones;
some
any
the
to
system
and
(plural
glomeruli)
knot
is
stimulates
infects T-cells
immune
in
collection
opportunistic
of
these
maintaining
is AIDS
near
conditions
within
a
Bowman’s
of
the
kidney;
equilibrium
the
body
dynamic
capsule
nature
cortex
within
of
transport
the
(HIV)
increase
homeostatic
in
that
and
cells
the
electron
cells
ineffective
homeostasis
capillaries
in
mast
virus
leading
constant
of
carbohydrates
are
an
glomerulus
compounds
by
as
hormone
system
attraction
carrier
such
local
infections;
Schwann
electrical
in
of
that
concentration
compounds,
histamine
obtains
carbon
inammation
ecosystem
a
that
complex
secreted
an
organism
carbon from
HIV/AIDS
gradient
charged
membrane
electron
at
arrows
interrelated food
carries
stimulated
levels;
direction
the
them
gland
when
and
organisms
hormone
electrochemical
an
physical
inuence
action
or
the
between
muscle
an
nerve
all
site
of
homeostasis
involving
of
continuous
chain
monitoring
and
ultraltration
electron
transport
chain
regulation
(ETC )
glucagon
series
of
compounds
that
alternately
reduced
and
hormone
energy
to
form
a
by
in
pancreas
immune
immune
in
conditions
response
type
of
that
to
increase
internal
islets
humoral
oxidised
Langerhans
stimulates
transfer
secreted
are
of
of
blood
response
in
which
glucose
antibodies
proton
are
secreted;
effective
concentration
against
gradient
gluconeogenesis
emphysema
lung
disease
in
are
damaged
and
the
of
the
lungs
always
synthesis of
a
population
in
a
glucose, for
example
place;
species
only found
in
a
systolic
blood
blood
pressure
pressures
above
140
liver
mmHg
and
diastolic
pressure
is
glucose
above
of
concentration when
a
in the
present
specic
cells
high
glycogen
when
to decrease
in
host
hypertension
decreases
of a disease
remain
acids
surface
from
endemic
that
glucose
outside
amino
glycogenesis
area
of
which
from
alveoli
formation
pathogens
stimulated
90
mmHg
most
of
the
time
by
hypothalamus
specic
part
of
the
brain
that
insulin
controls
place
glycogenolysis
endocrine
gland
see
ductless
inner
layer
of
cortex
osmoregulation,
the
vascular
tissue
in
and
the
to
increase
the
activity
of
temperature
the
pituitary
blood
gland
concentration
when
stems
stimulated
energy
currency
idea
that
is
the
energy
glucagon
I
‘currency’
transactions
are
series
of
reactions
in
which
by
glucose
which
by
one
glycolysis
molecule, ATP,
is
converted
to
pyruvate
with
immune
response
changes
that
occur
made
transfer
in
liver
roots
glucose
and
in
body
glucose, for
that
example
surrounds
to form
including
of
gland
glycogen
endodermis
breakdown
activities
of
some
energy
in
to ATP;
the
specic
immune
system
in
cells
occurs
epidemic
an
outbreak
of
a
in
granum
ethylene
(ethene)
plant
cytosol
a
stack
stimulates
a
variety
of
of
thylakoids
in
site
of
light-dependent
of
immunoglobulin
photosynthesis
to
defend
against
type
of
protein
that
using
zoos
antibodies
and
immunology
gardens
to
away from
their
study
of
the
defence
H
conserve
against
species
ability
disease
ripening
conservation
botanical
antigens
the
infectious
forms
ex situ
to
immunity
a
responses
stage
including fruit
response
cells
hormone
chloroplast;
that
of
disease
disease
natural
habitat
the
place
where
an
organism
in situ
conservation
using
protected
habitat
lives
excretion
removal from
the
waste
products
of
substances
in
as
nature
reserves
various
denitions;
some
of
the
conserve
species
in
their
to
natural
metabolism
best
and
such
body
health
of
areas,
excess
incorporate
physical,
mental
habitat
of
and
social
health;
see WHO
incidence
number
of
people
who
requirements
denition
on
page
128
helper T-lymphocyte
develop
type
of T-cell
over
a
a
disease
certain
or
are
period
of
diagnosed
time
F
that
facultative
uses
anaerobe
oxygen for
survive
without
organism
respiration,
it
in
that
but
avin
can
anaerobic
fatty
liver
droplets
of
182
in
liver
as
a
herd
result
an
ecosystem
shows ow
between
with
B-cells
mechanisms
to
secrete
of
uid
of
drinking
the
liver;
alcohol
in
from
tissues
of
vaccinating
the
protection for
immunised
pathogen
is
as
a
large
population;
those
transmission
reduced
non-specic
involving
capillaries
defence
leakage
and
surrounding
of
swelling
site
of
infection
insulin
hormone
Langerhans
immunity
provides
that
out
inammation
of
proportion
alcohol
diagram
and
stimulate
excess
of fat
cells
carry
inammation
associated
respiration
accumulation
chain
energy
in
to
to
antibodies
dinucleotide;
involved
inside
drinking
food
phagocytosis
hepatitis
adenine
coenzyme
cytokines
macrophages
conditions
FAD
secretes
stimulates
in
secreted
pancreas
decrease
in
by
islets
of
that
blood
glucose
concentration
not
of
a
interspecic
competition
competition for
individuals
of
resources
different
between
species
Glossary
intraspecic competition
for
resources
between
competition
individuals of
memory
that
cell
lymphocyte
remains
in
(B-
circulation
or T-cell)
after
nitrogen xation
nitrogen
gas
conversion
(N
)
into
of
ammonia
2
the
same
immune
species
antigen;
response
see
to
a
specic
secondary
node of
immune
Ranvier
action
response
gap
potentials
in
myelin
occur
in
where
myelinated
neurones
K
metastasis
site
Krebs
cycle
stage
of
of
cancer
primary
in
which
a
is
dehydrogenated
major
with
transfer
to
reduced
become
type of
elswhere
in
the
body
NAD,
histocompatibility
cell
surface
of
proteins
reduced
used
to
display
antigens
photophosphorylation
phosphorylation that
photolysis
which
of
are
energy
to
and
complex;
decarboxylated
tumour
non-cyclic
2-carbon
MHC
fragment
travel from
aerobic
established
respiration
cells
of
reduced
water
and
involves
production
NADP
non-specic defence
system
to
mechanical,
FAD
cellular
and
chemical
lymphocytes
defences
and ATP
MHC
class
proteins
I
on
body
macrophages
present
L
antigens
of
and
respond
to
pathogens
cells
quickly
except
that
B-cells
but
always
in
the
same
way
that
intracellular
O
parasites
lactate
3-carbon
compound
that
is
MHC class II
the
end
product
of
and
respiration
in
animals
and
some
B-cells that
interior of
stage
reactions
present
mitochondrial matrix
bacteria
light-dependent
proteins on
macrophages
obesity
body
that
reaction
antigens
enzyme-rich
mitochondrion;
and
Krebs
suitable for
site of
cycle of
than
link
in
grana
light
of
chloroplasts
energy
to
that
monoclonal
chemical
single
antibody
specicity
antibody
secreted
by
a
in ATP
and
aerobe
an
of
survive
reduced
NADP
of
hybridoma
stage
reactions
morbidity
occur
an organism that
survives where there
in
stroma
triose
of
chloroplasts
phosphate
using ATP
motor
sickness
neurone
transmits
or
reduced
NADP from
light-
nervous
nerve
cell
person
impulses from
system
to
dependent
mutualism
stage
that
is
two
(or
together for their
in
that
ineffective
system
central
coating
a
pathogen
with
effectors
more)
species
mutual
or
antibody
molecules
living
to
any factor
with
that
the
complement
limiting factor
no oxygen
disease
illness
opsonisation
and
is
cells
immune
to form
that
oxygen
a
infects
that
than
greater
organism
without
opportunistic disease
light-independent
more
is
clone
only
energy
20%
BMI
respiration
obligate anaerobe
transfer
is
height;
30
obligate
cannot
occur
mass
anaerobic
make
it
easier
to
be
engulfed
by
a
benet
phagocyte
shortest
supply
and
myelin
therefore
layers
of
cell
membrane
made
oxidation
prevents
a
biological
process,
such
as
by
Schwann
cells
as
the
photosynthesis,
proceeding
loss
oxidative
myelinated
neurone
nerve
a
surrounded
method for
population
by
insulatory
layers
reaction
reaction
in
respiration
myelin
size
made
by
Schwann
by
is
converted
see
in
nal
stage
which ATP
chemiosmosis;
is
occurs
inner
mitochondrial
membranes
which
to
the
volume
of
oxygen
N
acetyl
that
coenzyme A;
and
cells
oxygen debt
pyruvate
electrons
of
on
link
of
phosphorylation
aerobic
synthesised
determining
loss
hydrogen
cell
of
index
the
of
neurones
any
faster
Lincoln
is
insulation for
is
absorbed
after
exercise
to
pyruvate
NAD
nicotinamide
respire
adenine
lactate
and
restore
oxygen
dehydrogenase
dinucleotide;
lipoprotein
particle
that
coenzyme
involved
in
oxygen decit
respiration
lipids
in
the
epidermis
layer
of
cells forming
nicotinamide
lowest
layer
in
a
and
blood
between
cell
made
in
the
is
part
of
the
coenzyme
demand for
respiration
oxygen for
during
exercise
aerobic
and
in
photosynthesis
volume
the
supplied
bone
natural
that
the
adenine
phosphate;
leaf
involved
marrow
muscle
difference
protective
dinucleotide
lymphocyte
in
the
blood
NADP
lower
concentrations
transports
immunity
immunity
gained
specic
by
infection
or
antibodies
transferred
P
immune
system;
see
B-lymphocyte
from
mother
and T-lymphocyte
negative feedback
that
set
maintain
point
to
palisade
control
mechanism
returns
a
value
to
its
homeostatic
cells
mesophyll
in
the
upper
mesophyll
immediately
beneath
layer
tissue
the
of
of
a
leaf
upper
M
epidermis
equilibrium
macrophage
presents
tissue
antigens
phagocyte
and
that
neutrophil
destroys
blood
pathogens
mass ow
direction;
phloem
mast
to
e.g.
direct
cell
a uid
xylem
in
sap
one
and
part
system
by
of
to
infection
or
secreting
the
non-specic
destroys
in
the
present
in
the
increase
during
infections
nitrate
nitrifying
conversion
ions
by
bacteria
Nitrobacter
respectively
reactions
disease
continent
pathogens;
blood
pandemic
parasite
use
in
of
ammonia
bacteria
Nitrosomonas
ammonia
their
living
passive
and
and
nitrite
energy-transfer
by
or
and/or
inside
or
whole
receiving
source,
mother
e.g.
that
across
obtains
a
host
organism
immunity
gained
antibodies from
by
across
a
world
protection from
on
immunity
breast
present
the
organism
nutrition
nitrication
to
responds
damage
histamine;
defence
blood,
of
sap
cell
that
numbers
movement
phagocyte
injection
the
another
or from
placenta
and
in
milk
183
Glossary
pathogen
a
percentage
quadrat
that
particular
petiole
to
a
disease-causing
cover
of
stem;
phagocyte
such
as
phloem
a
leaf
leaf
that
in
a
tissue
e.g.
of
the
bone
material,
viruses
which
sucrose
a
transports
and
amino
of
factor
to
e.g.
during
an
by
hypothalamus
apparatus for
rates
of
leafy
twigs
water
blood
into
that
of
to x
prevalence
immune
of
the
light
as
a
specic
antigen
it
has
producer
an
that forms
that
is
chain
the rst
making
used
to
of
simple
the
rate
apparatus
–70
any
drug
that
the
difference
of
order
–60
bisphosphate
compound
(RuBP)
that
dioxide
acceptor
is
in
the
the
stage
of
light-
photosynthesis
in
vaccinating
contact
with
a
all
those
person
with
a
specic
transmission
disease
in
to
the
mind
immediate
risk factor
becomes
habit-forming
the
any factor
chance
rituximab
difcult
to
of
increases
developing
a
disease
drug
to
give
it
drug
based
on
a
up
monoclonal
photosynthesis
circulation
that
so
the
cravings for
area
drug-
the
it
potential
membrane
has
of
pulmonary
of
mV
prevent
are
to
heterotrophs
carbohydrates
of
cell
infected
making
measure
a
people
there
photosynthometer
used
respiration
trophic
use
drive
of
energy
process that
taking
synthesis
rate
ring vaccination
a food
on
to ATP
autotrophic
psychological dependence
energy
apparatus
the
independent
effects
energy from
before
source
absorption
of
compounds
not
energy to drive formation of ATP
light
transfer
potential
carbon
to
between
immune
that
carbon
the
the
organic
5-carbon
in
ecosystem
of
organisms
ribulose
an
urine
division
the rst
in
to
blood
living
a
photosynthesis to
photosynthesis
an
the
the
time
response
psychoactive drug
light
people
one
to
available
in
of
any
to form ATP
photophosphorylation
place
at
autotrophic
uses
in
in
in
glomerulus
(GP)
to
appear
heat
across
process
to
capsule
number
disease
sensory
molecules
resting
a
level
takes
the
a
species
complex
blood
that
glucose
to
partitioning
resources
or
known
organism
energy
of
small
in
Bowman’s
(primary)
organism
resource
cell
maximum
of
starts
measure
encountered
an
it
respiration
use
action
neurone
renal threshold
before
plants
nerve
impulses from
concentration
is
measuring
by
motor
different
to force
the
system
photoautotroph
uptake
that
that
neurone
transmits
small
carbon
added
e.g. ADP
region
the
in
relay
that
neurone
a
made
response
compound,
gland
an
potential
a
potential
pituitary
pressure
3-carbon
also
chemical
is
action
in
of
in
respirometer
(PGA)
cycle;
phosphate
increase
depolarisation
hormone ADH
primary
which
change
the
from
3-phosphate
phosphorylation
a
and
elements for
produced
glycerate
an
immediately following
control
releases
with
as
leads
factor,
a
which
(ultraltration)
assimilates
in Calvin
in
pressure ltration
column
acid
mechanism
potometer
sap
tube
phosphoglyceric
compound
it
positive feedback
posterior
in
and
phloem
transport
attaches
engulfs foreign
sieve
xation
a
‘stalk’
sieve tube
phloem
by
that
made
bacteria
plant
acids,
a
cell
assimilates,
phloem
occupied
of
species
part
marrow
is
organism
percentage
antibody for
treatment
blood ow
(R)
by
production
of
of
oxygen
from
photosystem
pigments
and
around
a
reaction
is
a
chlorophyll
a
an
organism
stretch
by
absorbing
blood
that
gains
is forced
has
into
them
the
heart;
pressure
points,
e.g.
on
part
of
3-carbon
at
drug
tolerance
and
there
are
when
the
of
water
stem
in
by
osmosis
stroma
of
wrist
that
that
catalyses
the
is
of
carbon
dioxide
glycolysis
enzyme
has
catalyses
the
link
reaction
S
in
withdrawal
mitochondrial
symptoms
the
body
that
developed
the
compound
of
into
absorption
enzyme
xation
product
movement
roots
be felt
a
end
MabThera
by
can
rubisco
pyruvate dehydrogenase
metabolism;
the
chloroplast
reliance
become
pressure
following
of
as
arteries
its
the
it
of
molecule
pyruvate
as
recoil
light
physical dependence
drug
and
sold
back
from
at
energy
and
root
the
contraction
phototroph
lungs
centre
as
which
to
proteins
pulse
arranged
heart
cancer;
drug
is
matrix
not
Schwann
taken
myelin
cell
to
glial
cell
insulate
that
makes
neurones;
see
glial
Q
pituitary
below
gland
the
anterior
endocrine
gland
hypothalamus;
and
posterior
just
see
cell
quadrat
pituitary
apparatus
composition
of
a
used
in
analysing
secondary
pumps
community
gland
diffusion
plaque
region
of
an
artery
where
active transport
sodium
another
ions
out
gradient for
substance
so
cell
creating
sodium
that
a
and
moves
into
R
atheroma
has
plasmodesma
thin
developed
(plural
cytoplasmic
plant
the
plasmodesmata)
connection
between
cells
polyclonal
many
immunity
clones
of
B-
response
and
of
or T-cells
to
an
same
at
184
all
species
the
at the
centre
receptor
cell
energy
into
travel
same
the
individuals
living
time
in
the
of
the
same
place
the
gain
a
converts
molecule
a form
impulses
of
of
that
and
hydrogen
cannot
be
(or
any
of
time
when
stimulated
immune
same
transport
response
subsequent)
memory
cells
to
an
encountered
selective
period
the
protein
system
electrons
through
secondary
neurone
gain
period
neurone
a
photosystem
electrical
the
of
a
that
along
refractory
a
chlorophyll
centre of
reduction
antigen
population
reaction
cell
of
the
specic
antigen
that
by
immune
has
been
before
reabsorption
movement
substances from ltrate
blood
second
response
back
into
of
the
Glossary
sensory
neurone
nerve
cell
that
T
transmits
the
set
impulses from
central
point
factor
nervous
the
homeostatic
sieve tube
part
single
of
a
phloem
complete
e.g.
cell
sieve
of
above
the
number
once,
a
a
species
defences
that
a
is
each
mesophyll
and
process
within
blood
thylakoid
by
a
sent
which
blood
clot
vaccine
by
a
a
blood
vessel
within
respond
response
to
a
tissue
above
in
a
chloroplast;
is
a
activated
response;
also
is
stacks
of
granum
type
of
known
an
see
cytotoxic
layer
a
of
cells
translocation
sap
leaf;
inside
sieve
of
phloem
tubes
of an infectious disease
of
infected
loss
of
some
a
or
all
to
causative
uninfected
interruption
of
in
an
artery
an
immune
articial
active
varying
give
different
different
ventricular
a
acid
shapes
sequences
to
bind
organism
pathogen,
to
that
e.g.
Aedes
dengue fever
systole
ventricles
VO
antibody
antigen-binding
antigens
and
so
contraction
blood
artery
element
xylem
of
amino
of disease
aegypti
vessel
part
that forms
enters
and
cell
of
the
the
aorta
that forms
part
of
vessel
max
agent from
oxygen
maximum
person
during
is
rate
absorbed
at
aerobic
into
which
the
blood
exercise
loss
of
water
vapour
by
blood
diffusion from
supply
by
brain
transpiration
by
provide
site;
a
epidermis
functions
or
2
transfer
stroke
in
mouth
containing
stimulate
region
pulmonary
movement
transmission
lower
to
to
transmits
immune
as T-cell;
and
involved
by
immunity
vector
lymphocyte
during
e.g.
preparation
molecule
T-lymphocytes
of
the
space
procedure
vaccine,
antigen(s)
variable
blood
enclosing uid-
helper T-lymphocytes
antigen
lower
membrane
T-lymphocyte
that
a
injection
difference
impulse
vaccination
giving
hormone
potential
an
thylakoids form
of
is found
cellular
that
antigens;
immediately
species
system
mesophyll
the
of
percentage
which
different for
spongy
receptors for
when
response
thrombus
lled
specic defence
different
has
vessel
in
chemical
by
the
clot forms
body,
heart
area
quadrats
that
responds
which
thrombosis
one
the
so
neurone
in sh
unit
cell
threshold
tube
of
through
cell
hormone
stimulated
that forms
during
species frequency
in
part
circulation
travels
species density
per
target
physiological
equilibrium
element
circulation
blood
as
a
V
to
system
value for
maintained
receptors
supplying
aerial
parts
of
plants
W
the
transpiration
pull
loss
of
water
by
brain
withdrawal
transpiration
stroma
enzyme-rich
interior
causes
movement
symptoms
associated
water
chloroplast;
site
of
the
symptoms
of
of
through
the
xylem
with
abstinence from
by
lightdrug-taking
cohesion–tension
independent
stage
of
photosynthesis
transpiration
suberin
waxy
substance
that
does
movement
allow
water
and
ions
plant
between
sap
in
continuous
the
X
xylem
phosphate
3-carbon
compound
cells; forms Casparian
xylem
that
strip
of
to ow
triose
between
stream
not
endodermal
is
an
intermediate
in
plant
water
cells
and Calvin
tissue
and
ions
xylem vessel
trophic
and
transports
provides
support
cycle
substrate-linked
phosphorylation
which
glycolysis
level
feeding
level
in
a
column
of
xylem
a food
vessel
phosphorylation
elements for
transport
of
chain
of ADP
to form ATP
that
occurs
in
water
the
tumour
active
site
of
an
enzyme
with
a
mass
of
cells
that
has
a
plant
grown
xylem vessel
in
from
association
a
in
one
mutated
cell
that
forms
substrate
dividing
element
a
cell
that
began
a
xylem
vessel
uncontrollably
molecule
symplast
pathway
through
Z
plant
U
tissues
in
which
substances
travel
Z-scheme
from
cell
to
cell
through
unmyelinated
neurone
nerve
cell
diagram
electron ow
plasmodesmata
is
not
surrounded
by
place
adjoin;
where
includes
synaptic
two
pre-
neurones
and
membranes
post-
and
layers
upper
synaptic
cleft
cleft
gap
between
two
epidermis
layer
of
topmost
nitrogenous
an
or
effector
systemic
heart
with formula CO(NH
systole
heart;
lungs,
blood from
in
and
contraction
atrial
ventricular
neurone
and
urea
cycle
reactions
ammonia
everywhere
the
a
cell
circulation
to
except
between
body,
back
phase
systole
systole
the
the
of
the
photosynthesis
and
a
leaf
)
2
that
carbon
in
product
convert
dioxide
into
urea
ureter
from
is followed
of
protective
layer
excretory
2
neurones
represents
light-dependent
myelin
cells forming
urea
synaptic
of
in
insulatory
stage
synapse
that
that
muscular
tube
kidney
the
to
that
moves
bladder
urine
by
peristalsis
by
urethra
urine
muscular
tube
travels from
the
through
which
bladder
185
Index
Key terms
are
in
bold
biological diversity
community
(biodiversity)
companion
50–61
70S
ribosomes
7
,
40
cells
74,
75,
76,
77
25
biological
pyramid
biotic factors
42–3
48
competition
48
competitive
exclusion
48
A
blood
abiotic factors
absorption
48,
59
spectrum
acetyl-coenzyme A
acetylcholine
91,
82–3,
blood
10
94,
pressure
blood
sugar
blood
vessels
96,
151
85,
88–9,
124,
spectrum
121,
151,
immunity
mass
84–5,
86–7
cooperation
42,
43,
143,
145,
146–7
,
148,
154
coronary
creatine
index
gardens
(ATP)
4–5,
46
heart disease
phosphate
161
33
166
cristae
57
crop
24,
28
production
capsule
113,
114
cuticle
17
6
making
28,
37
,
34
cyclic
photophosphorylation
11
13,
brewing
35
cytosol
12
47
cytotoxic T-lymphocytes
adhesion
44,
48
129
bread
24,
41,
145
152
adenosine triphosphate
23,
40,
144,
56–7
123
Bowman’s
20,
consumers
55,
10
botanic
acute disease
53,
125
body
active
conservation
143,
125
149,
potential
161
104–5
B-lymphocytes
action
114,
proteins
26
acetylcholinesterase
action
91,
complement
147
,
149
71
C
ADP
11,
20,
23
adrenaline
91,
D
103
Calvin
aerobic
exercise
162,
cycle
cancer
aerobic tness
9,
12–13,
17
135,
154–5,
177
deamination
110,
111
162–3
capillaries
aerobic
5,
165
respiration
20,
22–9,
33,
82,
84–5,
113,
114
decarboxylation
26,
27
36–7
,
capillarity
70
decomposers
40,
41,
44,
46,
49
96
carbaminohaemoglobin
AIDS
132–3,
136–7
,
168,
all-or-nothing
rule
20,
158
demyelination
2–3
dengue fever
dioxide
2,
3,
concentrations
acids
12,
46,
46–7
,
34,
107
denitrication
110–11,
pituitary
antibiotics
168
antibodies
143,
20, 32–5, 36–7
, 96
gland
144,
108
147
,
148,
150–1,
antidiuretic
hormone
(ADH)
103,
12
135,
cardiac
cycle
cardiac
efciency
174,
177
cardiovascular
164
cell-mediated
presentation
143,
antitoxins
146,
151,
85,
91,
66,
147
,
cells,
148,
149,
150
152
92,
pathway
aquaporins
145
67
,
70,
161
immune
116
158–9,
disease
response
147
,
chemiosmosis
4,
between
24–5,
102–3
keys
28
DNA
2
7
,
double
chloroplast
envelope
chloroplast
pigments
7
,
12
drug
84–5,
indexes
24,
25,
tubules
85,
87
,
89,
7
,
8,
9,
10
74,
160,
synapses
bronchitis
75,
124–5
168–77
129
systole
102
system
64,
82–97
,
161
E
160
170–1
92
climateric
atrioventricular
autotrophs
glands
129
161
cirrhosis
atrial
175
76
circulatory
atherosclerosis
169,
169
152
chronic disease
atheroma
82
169
10
ductless
64,
135
circulation
abuse
drugs
immunity
chronic
assimilates
113,
114
cholinergic
active
(DCTs)
61
132,
drug tolerance
articial
142–55
136–8
160
chloroplasts
arterioles
7
128–9
against
drug dependence
82,
6,
116
diversity
2
58
plants
convoluted
115,
134
92
160–1
49,
statistics
distal
communication
chemotrophs
76
86,
defence
chemoautotrophs
93
diastole
diet
67
49
mellitus
dicotyledonous
diseases
strip
44,
diabetes
dichotomous
92–3
149
116–17
apoplast
carcinogens
Casparian
154–5
arteries
145
47
169
detritivores
174
46
anaerobic respiration
82,
depressants
158
carboxylation
antigens
16–17
12
110
ammonication
aorta
30,
14–15,
9,
carboxyhaemoglobin
ammonia
antigen
171
130–1,
46
carbon xation
152,
27
48
amination
anterior
26,
122
carbon
amino
23,
170–3
carbon
altruism
dehydrogenation
138
carbohydrates
alcohol
96
2,
node
8,
(AVN)
90–1,
respiration
rate
106
ecological
efciency
ecological
niches
44–5
92
clonal
expansion
clonal
selection
147
40,
48
46
closed
ecosystems
147
circulation
40–5,
biodiversity
82
48–9
50–61
B
coenzyme A
bacteria
142,
144,
balanced diet
186
151
158–9
26
effectors
cohesion-tension
collecting
ducts
71
(CDs)
100,
101,
electrochemical
113,
115,
116,
117
electron
carriers
102
gradient
10
11,
122
Index
electron transport
20,
24,
embryo
banks
emphysema
energy
currency
energy ow
epidemics
143,
HIV/AIDS
132–3,
homeostasis
hormones
144
2,
4
44
101,
morbidity
105
mortality
immune
hypertension
43,
monoclonal
equilibrium
response
147
,
148–9
20,
acids
(EAAs)
(EFAs)
122
neurones
muscle
121
90
N
responses
143,
147
,
148–9,
NAD
151
106–7
immunity
56–7
in
164–5
situ
(Ig)
conservation
8,
natural
150
21,
9,
22,
23,
10–11,
immunity
nephron
136
nervous
144
112–13,
system
24,
12,
28,
13,
32,
34,
170
17
152
negative feedback
55
incidence of disease
inammation
20,
NADP
152–3
immunoglobulins
110–15
162–3,
120,
I
immune
(ethene)
28
154–5
138–9
158
34
conservation
excretion
158
26,
121
myogenic
acids
25,
(Mabs)
48
myelinated
116
32
24,
136–8
neurones
myelin
100–1,
130
amino
motor
28,
matrix
antibodies
data
mutualism
125
161
hypothalamus
24–5,
mitochondrial
151
102–7
hyperpolarisation
40–1,
mitochondria
136–7
,
100–1
homeostatic
130
158
essential fatty
exercise
histamine
humoral
2–3,
ex situ
9,
67
energy
ethylene
8,
176
endodermis
ethanal
(ETC)
57
endemic diseases
essential
chain
28
101,
105,
117
117
120–5,
171
F
insulin
facultative
FAD
fats
27
,
20,
fatty
anaerobes
36
28
158,
liver
160–1
103,
104–5,
neurones
134
interspecic
competition
48
intraspecic
competition
48
ions
66,
67
,
70,
96,
121,
neutrophils
nicotine
174,
nitrifying
34–5
nitrogen
120–3,
83,
143,
124,
125,
171
144
174–5
nitrication
122
170
fermentation
102,
47
bacteria
47
46
K
bre
158
tness
keystone
162–5
food
chains
food
webs
40–1,
fruit,
ripening
kidneys
43
Krebs
41
species
104,
cycle
52,
111,
20,
53
112–17
21,
22,
nitrogen xation
46–7
nodes of
121
Ranvier
non-cyclic
24,
26–7
,
107
28,
32
photophosphorylation
non-specic defence
nutrients
41,
system
11
142–3
158
L
G
O
lactate
gas
exchange
genetic
germination
glial
30,
diversity
cells
glomerulus
22,
113,
104,
glycogen
23,
23,
grana
guard
limiting factors
105
Lincoln
105
27
,
link
104–5
105
glycogenolysis
glycolysis
20,
22–3,
24,
6–7
,
8–9,
stage of
Henle
obligate
anaerobes
12–13
opsonisation
26,
115,
36
36
28,
32
oxidation
9,
132
151
osmoregulation
oxidative
116–17
26,
23,
27
47
phosphorylation
20,
28–9,
32
117
oxygen
6
14,
20,
30,
32–3,
36,
94–5,
96–7
,
164–5
176–7
oxygen debt
83,
159
aerobes
opportunistic diseases
170–1
113,
epidermis
lymphocytes
lysis
8–9,
24,
160,
lungs
71
17
158,
obligate
oxaloacetate
160
of
10–11,
16–17
20,
105,
obesity
60
liver
33,
10
stage of
lipoproteins
lower
32
index
reaction
loops
105
21,
7
cells
of
photosynthesis
114
33
glycogenesis
structure
light-independent
121
gluconeogenesis
glucose
33
photosynthesis
112,
103,
32,
light-dependent
56–7
31
120,
glucagon
leaves,
164–5
51,
20,
143,
146–7
33
oxygen decit
33
23
H
P
M
Haber
process
haemoglobin
47
94–5,
hallucinogens
health
malnutrition
168
128–9
statistics
heart
palisade
85,
136–9
86–7
,
90–3,
148,
149,
170
immunity
heterotrophs
2
153
159,
64,
mast
143,
cells
cells
metastasis
MHC
151
hepatitis
147
,
143,
mass ow
memory
161
helper T-lymphocytes
herd
macrophages
96–7
I
class
II
minerals
145,
147
,
171
149,
147
,
151
148
149
immunity
passive
smoking
pathogens
49,
phagocytes
phloem
7
142
passive
phloem
6,
138
percentage
149
147
,
mesophyll
pandemics
parasites
144
148,
145,
158
160
78
135
proteins
class
144,
6,
142,
cover
143,
64,
152
175
144–5,
65,
147
,
149,
151
149
74–9
sieve tubes
phosphoglyceric
143,
60
65,
acid
74–5,
(PGA)
76–7
,
79
12
187
Index
phosphorylation
24–5,
27
,
4,
11,
20,
21,
rituximab
23,
RNA
28–9
photoautotrophs
root
2
photophosphorylation
photosynthesis
2,
photosynthometer
photosystems
phototrophs
66–7
,
rubisco
14–15,
13,
17
10
pull
stream
triose
S
103,
cells
systems
phosphate
levels
(TP)
40–1,
tumours
secondary
active transport
secondary
immune
67
,
75,
135,
177
115
banks
response
151
57
reabsorption
114–15
ultraltration
122
unmyelinated
neurones
120,
neurones
point
100,
sieve tube
101,
upper
116
epidermis
pituitary
gland
103,
elements
index
of
74
diversity
61
urea
110,
urea
cycle
110–11,
110,
74,
75,
76,
77
,
ureter
78–9
111
72–3
sino-atrial
49,
pressure ltration
(SAN)
90–1,
urine
92
tests
effects
of
117
174–7
114
sources
pressure ow
node
52
smoking,
76–7
,
74,
75,
76,
78–9
V
78–9
species
prevalence of disease
40
136
vaccination
diversity
immune
response
51,
52–3,
species density
primary
40,
41,
42,
43,
131,
140,
species frequency
regions
150
60
47
vasoconstriction
specic defence
20,
143
60
44
variable
36,
153
58–61
151
vaccines
prokaryotes
116
110–11
116
sinks
potometers
46,
150,
system
sperm
gradients
5,
20,
24,
29,
banks
56–7
vectors
tubules
101
76
spongy
convoluted
101
143
158
vasodilation
proximal
6
123
Simpson’s
proteins
121
154
40
positive feedback
producers,
114
76
set
primary
23,
44
U
immunity
population
predation
12–13,
121
175
sensory
posterior
9,
42–3,
116
selective
polyclonal
70
64
83
plasmodesma
proton
70–1
160
82,
142
70–3
transpiration
trophic
gland
76–9
transpiration
transport
seed
plasma
transpiration
16
Schwann
plaques
71
71
12,
74,
transmission of disease
2
physical dependence
pituitary
translocation
132
pressure
roots
11
8–17
154–5
130,
(PCTs)
mesophyll
6,
130
12
113,
veins
standing
crop
82,
84–5
43
114–15
vent
step
psychoactive drugs
tests
communities
ventricular
stimulants
psychological dependence
6,
elements,
xylem
68
70
82
viruses
stroke
pulse
3
92
168
vessel
circulation
systole
175
stomata
pulmonary
2,
162–3
168
130–1,
132,
135,
142,
151
161
88
vitamins
stroma
pyramids,
ecological
7
,
9,
11,
12
42–3
VO
suberin
pyruvate
20,
24,
26,
32,
33,
67
max
164
2
34
substrate-linked
pyruvate dehydrogenase
phosphorylation
4,
26
23,
W
27
succinate
dehydrogenase
27
Q
water
sucrose
quadrats
158
23,
symplast
60
74,
76–7
,
pathway
synapses
102,
78–9
in
diet
in
plants
synaptic
cleft
66–73
124–5
wine
R
158
67
making
withdrawal
systemic
reaction
centre
100,
circulation
82,
symptoms
175
88
11
systole
receptors
35
124
103,
104,
105,
125,
86,
92
X
146,
147
T
reduction
9,
12,
20,
xylem
6,
64,
xylem vessel
refractory
period
65,
neurones
123
target
120
renal threshold
cells
temperature
104
partitioning
respiration
2,
control
testosterone
65,
68–9,
100–1
48
threshold
103
20–37
122
thrombosis
160
yeasts
respirometers
resting
30–1
potential
122,
thrombus
123
thylakoid
34–5
160
7
,
10,
11
Z
ribulose
bisphosphate
ring vaccination
153
risk factors
134
188
129,
74,
(RuBP)
12,
13
T-lymphocytes
149,
143,
151
tobacco
68
103
Y
resource
68–71,
elements
xylem vessels
relay
67
,
28
168,
145,
146–7
,
148,
Z-scheme
174
zoos
56
11
70,
71
78
64
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