Topic
2
Cells
1A- Levels of organisation
LEVEL 1 - Cells
Are the basic unit of structure and function in living things.
May serve a specific function within the organism.
Contain organelles
Examples- blood cells, nerve cells, bone cells, etc.
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LEVEL 2 - Tissues
Made up of cells that are similar in structure and function and which work together to perform a specific
function.
Examples:
1-.xylem tissue in the vascular bundle of plant for water transportation.
2-Palisade tissue in leaf specialised to carry out photosynthesis.
3-Muscle tissue in wall of stomach in animals to make the walls be able to churn food mix it with
enzymes by contracting.
4-blood tissue contains RBCs for carrying oxygen& WBCs for destroying harmful bacteria.
LEVEL 3 - Organs
Made up of different tissues that work together to perform a specific function or group of functions.
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Examples -1-In animals: heart, brain, skin, stomach, kidney,lungs.
2- in plant, a leaf is an organ for manufacturing of carbohydrates by photosynthesis.
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LEVEL4 - Organ Systems
A group of organs , carrying out separate functions and these functions combine to achieve major
process.
Examples - circulatory system, nervous system, skeletal system, etc
Flower is an organ system for reproduction( formed of sepals,petals,stamen &carpels).
1.
2.
3.
4.
5.
6.
7.
Dr
Level5 - organisms
Entire living things that can carry out all basic life processes. Meaning they can:
Take in materials ( nutrition)
Release energy from food (respiration)
Release wastes (excretion)
Grow (growth)
Respond to the environment( sensitivity)
Reproduce. (Reproduction)
Move (movement)
MRS.GREN
Usually made up of organ systems, but an organism may be made up of only one cell such as bacteria.
Examples - bacteria, amoeba, mushroom, sunflower, human
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Level5 - organisms
Entire living things that can carry out all basic life processes. Meaning they can:
Take in materials ( nutrition)
Release energy from food (respiration)
Release wastes (excretion)
Grow (growth)
Respond to the environment( sensitivity)
Reproduce. (Reproduction)
Move (movement)
MRS.GREN
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Usually made up of organ systems, but an organism may be made up of only one cell such as
bacteria.
Examples - bacteria, amoeba, mushroom, sunflower, human, plant.
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The levels of organization in the correct order then are:
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cells --> tissues --> organs --> organ systems --> organisms
Dr
1.
2.
3.
4.
5.
6.
7.
Cardiac
muscle cell
Cardiac
muscle tissue
Heart
Organ
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Circulatory
system
Human
A- The cells
All living organisms (except viruses) are made of living cells.
Cells are very small and can only be seen by light microscope.Mitochondria.
1-Animal and plant cells
A typical cell has : cell membrane, cytoplasm, and a nucleus.
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Small temporary
vacuole.
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Table 1-Comparison of plant and animal cells.
Points of comaprison
Animal cell
Plant cell
✔
✔
2-cytoplasm
✔
✔
3- Nucleus
✔
✔
4-cell wall
✖
✔
5- chloroplast
✖
✔
Only in leaf but not in root cell
✔
Small and temporary vacuoles
✔
Large permanent vacuoles
containing food stored in cell sap.
✖
Sometimes have glycogen granules
✔
Often irregular in shape
Often regular in shape
Dr
1- cell membrane
6-Vacuole
7- Starch grains
8-shape
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Functions of different cell organelles
Main cell organelles
organelles found only
in plant cell
1-Cell membrane
A very thin layer of protein
and fat.
1-Cell wall
Made up of cellulose which
Controls the movement of
substances in and out of the
gives the plant cell
strength,support &
protection.
(If the cell absorbs a lot of
water and swells, the cell wall
stops it bursting)
Freely permeable
!!
cell( partially permeable)
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on the chromosomes)
!
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3-Nucleus.
Contains genetic material,
(DNA which makes up genes
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2-Cytoplasm.
Jelly made of about 70%
water,contain many
substances especially
protein.
Site where metabolic
reactions(chemical reactions
for life) take place.
Controls all cell activities
and characteristics.
Dr
5- Ribosomes*
Tiny dots attached to the network of
rough endoplasmic reticulum.
They are places where amino acids are
joined together to form proteins
( polypeptides) where reaction is
controlled by enzyme & transported
by vesicles .
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(Starch grains made by
photosynthesis found inside the
chloroplast or in cytoplasm).
Notice : not all plant cells have
chloroplast.
3-large vacuole.
A space in a cell surrounded
by membrane, containing
solution of salts and sugars
called cell sap which keeps
the cell turgid; where a full
vacuole presses outwards on the
rest of the cell thus helps the cell
keeps its shape.
4- Mitochondria
Found in almost all cell
except prokaryotes.
Are the power house of
cell, where inside them oxygen
is used to release energy from
glucose by aerobic respiration.
2-Chloroplast.
Contains green pigment
called chlorophyll, that
absorbs sunlight for
photosynthesis.
Notice:
Animal cells have:
1- Vesicles: which are much smaller membrane - bound
space, than plant cell vacuole, which might contain food
or water. Also they have small temporary vacuole.
2- Glycogen granules( tiny grains) instead of
starch grains in plant cells, as a form of carbohydrate
storage.
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2- Specialised cells
Table 2 -Examples of specialised cells.
Specialised cell
Function
Adaptation
1-Palisade cells
Absorb sunlight and make nutrients.
⛅ Found below the epidermis
of leaf.
Packed with chloroplasts. Regular
shaped, closely packed cells form a
continuous layer for efficient
absorption of sunlight for
photosynthesis.
2-Root hair cell
Take in water and mineral ions from
soil.
1-Have long 'finger like
projection' with very thin wall
that increases the surface area for
more water& mineral intake.
2-Have a large number of
mitochondria which release
energy from glucose during
respiration in order to provide the
energy needed for active
transport of mineral ions.
3- A concentrated vacuole to help
absorbing water by osmosis
4- Covered with sticky material to
slide easily between particle.
A-Plant
cells
1- Transport water and mineral
salts from roots to stem, leaves,
flowers and fruits..
2-Provide support for parts of
plant above the ground(shoot)
⛅ In stem, roots and leaf of
plants.
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3-Xylem vessels
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⛅ Near the ends of plant roots
B-Animal
cells
Cilia
1-Ciliated cell
Layer of mucus which
traps dirt & microbes
Sweeps mucus carrying dust and
bacteria out of the lungs so as not to
get blocked .
⛅ Lining the trachea and
bronchi.
Notice:
1-goblet cells: found in gut.
Ciliated
cells.
2- ciliated cells: in oviduct& sperm duct.
Goblet cells secret mucus
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3- ciliated & goblet cells: in trachea &
bronchi.
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1- Transport:
a)-They are made of dead cells, with
no nucleus and no cytoplasm so,
water can pass freely.
b)- No end walls so that many cells
can form a continuous tube.
c)- they run from the roots right up
through the stem to leaves.
2- Support:
They have thick cell wall containing
lignin which helps to resist bending
strains by wind.
Goblet cells produce mucus which
traps dust and bacteria.
Ciliated cells have thin hairy
projections( hair) ,which sweeps
mucus out of lungs up to the
back of throat to be swallowed
and killed by acid in stomach.
Table 2 -Examples of specialised cells.-2
Contains haemoglobin to carry
oxygen from lungs to all body cells
where aerobic respiration occurs.
⛅ In blood of mammals.
1-The cytoplasm is filled with
haemoglobin which carries
oxygen.
2-Shape"Biconcave" increases the
surface area speeds up the rate at
which oxygen can diffuse in and out
of RBCs.
3-No nucleus, so the whole cell is
full of haemoglobin.
4- Flexible, small size where the
can be squeezed through even the
narrowest capillaries.
3- Muscle cells
To cause movement when they
contract
1- They are long and thin, so they
can be brought closer together
forming a contractile tissue.
2-Have protein fibres in
cytoplasm, which can shorten
(contract) the cell when energy is
available.
3- Many mitochondria in
cytoplasm for releasing energy
needed for contraction.
4- Nerve cell
Transmit nerve impulses inform of
electrical signals all around your
body.
⛅ Through out the body of
animals.
The cell has:
1- Long fibre called an axon along
which impulses travel.
2- A fatty sheath which gives
electrical insulation.
3- Many -branched endings which
can connect with many other cells.
Fetrilises the egg cell (female
gamete) and fuse together to
produce a zygote.
⛅ Produced in testes in huge
numbers( 300000000 per
ejaculation)
1-Head:
A- contains nucleus carrying the
genetic material.
B- produces enzyme that helps
penetrate the eg cell membrane.
C-Streamlined shaped which helps
in faster swimming& penetration of
egg
d- no cytoplasm
2- Middle part
Full of mitochondria to produce
enough energy for movement.
3- Tail(flagellum)
Can swim by beating the flagellum.
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5- Sperm cell
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2-Red blood cell
Notice:
Dr
They are motile:
( streamlined head, lots
of mitochondria,
beating flagellum
6- Egg cell
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Fertilised by the sperm cell (male
gamete) and fuse together to
produce a zygote.
⛅ Produced in ovaries, one per
month.
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Eggs can't move, but cilia in cells
lining oviduct push them down to
uterus.
Each egg contains a large store of
food in its cytoplasm, when its
fertilised it uses the food to
produce an embryo.
Has a nucleus containing the
genetic material.
membrane because of their size..
Protein molecules can"t diffuse cross
depends on their concentration gradient.
The movement of glucose molecules
Glucose. (c)
Protein
Dilute sugar
solution
Wa
te
diffusion of water
rp
molecules.
ote
nti
al
gra
die
nt.
Partially
permeable
membrane
Water
molecules
Concentrated sugar
solution
1-Active transport.
Active transport
Moving
from down to up
so, energy
needed.
3- protein
carrier pushes
glucose
molecule into
the cell..
2- Carrier
protein
changes its
shape. The
energy
needed for it
to do this is
provided by
respiration in
the cell..
1- Glucose
molecule
enters the
carrier protein.
The movement of molecules and ions in or
out of a cell through a membrane through
protein carriers against a concentration
gradient, using energy from respiration..
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2- Osmosis.
It is the diffusion of water molecules
from a region of higher water potential
(diluted solution) to a region of lower
water potential(concentrated solution),
through a partially permeable
membrane through protein pores in
membrane.
Dr
Passive transport
It is the net movement of molecules
and ions from a region of their
higher concentration to a region of
their lower concentration down a
concentration gradient, as a
result of their random movement.
1-Diffusion.
needed.
!!!!!!!
no energy
Movement in and out of cells
!
Moving from
up to down so,
Topic 3
!
020
B20
1-Diffusion.
It is the net movement of molecules and ions from a region of their higher concentration to a region of their
lower concentration down a concentration gradient, as a result of their random movement.
Factors affecting rate of diffusion:
1- Steepness of concentration gradient.
The steeper the gradient,the faster the
particles diffuse.
2- The surface area of the exchange membrane
The larger the surface area of the exchange membrane,the faster the particles diffuse.
Like walls of small intestine( villi) and the surface of placenta which is highly folded.
3- Thickness of the membrane( diffusion distance):
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The thinner it is, the easier it will be for particles to go through it, the faster the diffusion rate.
Like membranes in lungs are very thin so that oxygen and carbon dioxide can diffuse between the
blood and the lung air spaces easily.
4- Temperature:
Increasing the temperature will give particles more kinetic energy, making them move
faster, thus increasing the rate of diffusion.
5- Maintenance of concentration gradient:
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As glucose molecules that cross gut into blood, are quickly removed by circulating
blood,so that their concentration doesn't build up and equilibrium is not reached.
6-size of molecule: the smaller the size of molecules ,the higher the rate of diffusion.
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Importance of diffusion:
In plants
In animals
In animals
Dr
In both( plants&animals)
In photosynthesis:
1-carbon dioxide diffuses from air
into leaves through the stomata.
2- Oxygen as a waste product
diffuses out of the leaf through the
stomata into the air.
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In gas exchange for
respiration:
Where the cell membrane of cells
are freely permeable to oxygen and
carbon dioxide, so they easily
diffuse in and out of cells.
In animals: occurs between
alveoli& blood and between cells
and blood.
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Some of products of digestion are
absorbed from ileum (through
villi)to blood by diffusion.
It is the diffusion of water molecules from a region of higher water potential
(diluted solution) to a region of lower water potential(concentrated solution), through
a partially permeable membrane
2- Osmosis.
A cell is surrounded by a partially permeable membrane, and water may cross this
membrane( as they are very small molecules).
A-If a cell is placed in a solution of lower water potential (concentration), water leaves by osmosis.
B-If the cell is placed in a solution of higher water potential (concentration), water enters by osmosis.
A-Plant cells and osmosis:
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Water
potential of
surroundings.
Cell surface
membrane..
Equalized state
Cell in solution of equal
water potential- so no
net movement of water,
cytoplasm just presses
against cell wall.
So balanced
concentration=equilibriu
m.
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Turgid cell
Cells in solution of higher water
potential:
a)-Water enter by osmosis through
cell membrane.
b)- The cytoplasm and vacuole will
swell.
c)- The cytoplasm will push hard
against the cell wall,
Thus stretching the cell and making
it firm ( turgid).
Turgidity is needed for
support by keeping stem
upright and leaves flat and
firm.
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Cellulose
cell wall.
Notice:
The plant cell has a ver strong cell wall
around it, which is. Much stronger than the
cell membrane and it stops the plant from
bursting.
Dr. Nihal Gabr
Flaccid cell
Cell in solution of lower water
potential than the cell
contents( concentrated
solution),:
a)- water leaves the cell by
osmosis.
b)- the cytoplasm shrinks and
stops pulling outwards on the
cell wall
So plant losses its
firmness , no support and
begins to wilt.
If the solution is very concentrated,
then:
a)- A lot of water will diffuse out of
the cell
b)- the cytoplasm and vacuole go on
shrinking.
d)- as cytoplasm shrinks further and
further into the centre of cell, the
cell wall gets left behind and the cell
membrane pulls(tears) away from
the cell wall.
The cell is said to be
plasmolysed.
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B- Animal cells and osmosis:
Animal cell have no cell wall, just a cell membrane. They are likely to suffer damage as a result of
osmosis, as shown in the following diagram.
Thus osmosis is potentially damaging to animal cells, so
animals have mechanisms to keep the blood plasma and the body fluids at the same water
potential as the cytoplasm of cells.
In mammals kidney plays a vital part in this process of osmoregulation.
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Crenated state
Cell in solution of lower
water
potential( concentrated
solution)
The cell loses water by
osmosis, shrinks and the cell
membrane becomes unevenly
creased( crenated)
The movement of molecules and ions in or out of a cell through the cell
membrane against a concentration gradient, using energy from
respiration..
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3- Active transport.
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Equilibrium state
Cell in solution of equal
water potential as the
inside of the cell
Haemolysis state
Cell in solution of
higher water potential
The cell takes in water
by osmosis, swells and
the cell membrane
bursts as there is no cell
wall to resist the
increased pressure
inside the cell.
Importance of active transport:
Dr
In plants:
Absorption of nitrate ions( minerals ) from soil by root her cells.
In animals:
In small intestine: Glucose can be actively transported from the lumen of the small intestine into the
cells of the villi.
In kidney: Glucose is actively transported out of the tubule and into the blood.
Diffusion
Active transport
Transports dissolved substances from high to
low concentration
Transports dissolved substances from low to
high concentration
Requires no additional energy input
Requires energy from respiration
Does not necessarily require protein carriers
in the cell membrane
Requires protein carriers in the cell
membrane
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FALSEST
Dr.Nihal
Gabr
Topic
4
Enzymes
Catalyst:
A substance that increase the rate of a chemical reaction without itself being
changed by the reaction.
Enzyme:
Protein molecules that function as a biological catalyst without being changed
and are specific in their function.
enzymes work:
Enzymes are specific, where each
enzyme has a specific active site which
fits with one substrate only.
1+2
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1-How
Substrate
The substance which is acted upon
by an enzyme at beginning of the
reaction to produce a product.
The substrate is with a
complementary shape to active site.
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Lock &key mechanism
The enzyme is like a lock( active site), into
which another molecule( substrate) fits like a
key forming enzyme substrate complex.
Then product leave active site unchanged.
2
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Metabolic reactions, catalyzed
by enzymes, are 2 types
Anabolic reaction
Dr
Catabolic reaction
Building up reaction.
Usually needs energy.
Breaking down reaction.
Examples:
Usually involves the release of energy.
1- photosynthesis.
Examples:
2Building
up
of
glycogen
in liver and skeletal muscles
1- respiration
( glucose molecules joined to form glycogen)
2- Digestion:
3- Building up of cellulose in plant cell walls
Starch.broken intoMaltose. By amylase.
(Glucose molecules join to form cellulose)
Proteins broken into Amino acids. By protease
4- Building up of starch in plants
Lipids broken into Fatty acids and glycerol. By lipasetoff
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( glucose molecules join to form starch)
Dr.Nihal Gabr
2- Properties of enzymes:
1. They are protein in nature.
2. They are biological catalysts : they speed up the chemical reaction without being used up or changed,
thus a small amount of enzyme can change a lot of substrate into products.
3. They are specific in their actions : so each enzyme acts only on one substrate catalysing one type of
chemical reaction.
4.
They are formed inside cells but they either act inside the cells' intracellular" or outside the cells
'extracellular'.
Extracellular
enzymes
intracellular enzymes
Enzymes released from the cells to perform
their function:
Starch.broken intoMaltose. By amylase
Lipids broken into Fatty acids and glycerol. By lipase
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Enzymes working inside the cells:
Harmful Hydrogen peroxide.broken in liver cells.
By catalase
Glucose build up into starch in plant storage
cells. By starch phosphorylase.
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5. They are made inactive at high temperature: this is because they are protein molecules, which
are damaged by heat.
6. Their activity is affected by 4 factors:
2- pH
3- Enzymatic concentration.
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4- Substrate concentration.
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1- Temperature.
Dr
1-Temperature
Increased heat
energy causes more
collisions between
enzyme &
substrate( molecules
have higher kinetic
energy)
1
2
3
At high
temperature, the
enzyme may lose
the shape of its
active site. So
substrate can no
longer fit. Its
denatured.
Optimum
temperature at
which the
enzyme work
fastest.
For measuring the rate
(activity)of an enzyme
controlled reactions:
Either by measuring the
decrease in substrate
concentration per unit time.
Or by measuring the increase in
product concentration per unit
time.
Each enzyme has an Optimum
temperature at which the enzymatic
activity is reached to maximum.
In Humans: at around 37 C
In plants: around 28 C to 30 C.
Bacteria living in hot spring: at
about 75 C.
Denaturation is always irreversible.
Dr. Nihal Gabr
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Itf
Pepsin( protease
in stomach)
works best at
pH=2( very
acidic).
Example.
2-pH
Enzyme work
fast at a pH
some where
around
optimum.
1
Amylase(in
mouth and small
intestine ) works
best at slightly
alkaline pH= 7.5.
2
A pH which is very
different from the
optimum pH, can
cause denaturation
of enzyme.
Optimum pH
at which the
enzyme
work
fastest.
3
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eggoSt☆
C
B
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3-Enzyme
concentration
From A to B............. Enzyme is a limiting factor
From B to C ...............substrate is a limiting factor.
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Increasing Enzyme Concentration will increase the rate of reaction, as
more enzymes will be colliding with substrate molecules.
However, this will only have an effect up to a certain concentration,
where the Enzyme Concentration is no longer the limiting factor.
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A
B
From A to B............. Substrate is a limiting factor
From B to C ...............enzyme is a limiting factor.
Dr
4-Substrate
concentration
A
C
Increasing Substrate Concentration increases the rate of reaction. This is
because more substrate molecules will be colliding with enzyme molecules, so
more product will be formed.
However, after a certain concentration, any increase will have no effect on the
rate of reaction, since Substrate Concentration will no longer be the limiting
factor. The enzymes will effectively become saturated, and will be working at
their maximum possible rate.
ggÉ€ˢ€tˢfˢF€ᵗFˢ
ᵗˢ
1-Limiting factor: Is the factor that limits the reaction rate in
any physiological process controlled by many variables( the other
factors which affect the process)
2-role of enzymes in sustaining life: lower the activation energy
needed for many chemical reactions( ex: respiration/digestion) as
without enzymes they would take place so slowly .
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A-Nutrition
Topic 5
Nutrition: is the process by which living organisms are able to obtain or to make food( organic substances&
minerals)
Where food supply them with:
1- Raw materials for repair , growth and development of body tissue.
2- molecules used in respiration for providing energy.
3- vital elements and compounds that enables raw material and energy to be used efficiently.
*Nutrition: is taking in of materials to obtain or make organic substances&
minerals; for energy , growth and development.
Types of nutrition
Heterotrophic nutrition
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Autotrophic nutrition
Self feeding
The way some organisms as green plants are able to make
their own organic material(food) using inorganic molecules in
presence of light energy through photosynthesis.
The way animals obtain their organic material(food) by
eating plants or other animals.
Point of
comaprison
1- monosaccharides:
Glucose
2- Disaccharide:
Maltose, sucrose, lactose.
3-polysaccharides:
Glycogen( store of excess
carbohydrate in humans)
Starch ( store of excess
carbohydrates in plants)
Cellulose( forms plant cell wall)
2-Proteins ( C, H, O, N)
Made of long chain of subunits called
-Amino acids, which are joined
together in a particular sequence
coded by genes.
( there are 20 different types of
amino acids).
3- Fats"Lipids" ( C,H,O)
Built up of glycerol and fatty
acids.
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1- Forms
1-Carbohydrates( C, H, O)
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A-The main nutrients( organic)
Dr
A typical protein is about 400 amino
acids long.The type of protein is
determined according to the
sequence of amino acids.
Certain sequence of amino acids
Amino acid
sequence 1
Amino acid
sequence2
Forms a protein molecule.
Which curls up into different shapes(forming a 3Dimensional shape)
Resulting in different shapes of protein molecules.
The three-dimensional shape of a protein determines its function.
Example2-The shape of
antibody molecule
determines which kind of
pathogen it can attach to.
Example:1-The shape of the
Enzyme molecule determines
which reaction it can catalyse.
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GRANDI
2-Importance
1-Carbohydrates( C, H, O)
1-A source of energy by
respiration.
(1gram glucose .....17KJ
energy)
Energy needed for:
1- Active transport.
2- Cell division.
3- muscle
contraction(movement).
4- manufacture of large
biological molecules.
2-Excess carbohydrates in
humans stored as glycogen
and fat.
3-solubilty
Sugars are soluble✔
Polysaccharides are insoluble✖
2-Proteins ( C, H, O, N)
3- Fats"Lipids" ( C,H,O)
1- For growth and repair by
1- An important source of
energy( energy store)
( 1gram ......39 kJ)
2- insulation:
A)- thermal insulation
beneath the skin( reduce heat
loss)
B)- electrical insulation
around nerve cells.
3- Fat cells protect vital
organs as heart.
4- Forms part of the cell
membrane.
5- cholesterol is important for
making sex hormones.
making new cells.
2- Formation of new materials
as:
-Catalysts( enzymes)
-Hormones( as insulin)
-Antibodies( for defense against
disease)
-Transport molecules( as
haemoglobin).
-Cell membrane( protein carrier).
-keratin ( in finger nails).
Amino acids are water soluble.✔
Some proteins are water soluble( ex:
Water insoluble✖
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Point of
comaprison
haemoglobin).✔
Other proteins are water insoluble
( ex: keratin in hair& finger nails)✖
4- Fate of
excess
1-In humans
Excess amino acids are
deaminated in liver and
excreted as urea.
Dr
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1- in humans
A)- changed to glycogen
stored in liver and muscle
cells.
However only small
quantities of glycogen can
be stored.
B)- any more is changed
into fat.
2- in plants
A)stored as starch. In their
seeds or tuber which we use
as food.
B)-part is used in making
cellulose in cell wall.
5- Food test:
6-Good source
1-Starch: iodine give s blue
black.
2- reducing sugars:
Benedict's reagent give
orange red and ppt.
1- Starch: rice ,potatoes,
wheat(pasta) and cereals.
2-Sugars: food sweetenings as in
desserts, sweets Nd soft drinks.
3-Glycogen: in liver
4- cellulose: in vegetables.
Dr. Nihal Gabr
Plants use some of their
carbohydrates in
combination with
ammonium or. nitrate ions
to make amino acids
1- in humans
1-Stored as adipose tissue
underneath the skin at
which the cells become
filled with large drops of
fats or oils.
This adipose tissue helps to
insulates the body.
2- animal fats contain
cholesterol which cause:
.A)-atherosclerosis( build
up in arteries)
.B)-obesity
C)-Heart disease.
D)-Increase blood pressure
E)-Diabetes.
which are thin linked to
2- In plants
Many plants store oils in
their seeds as peanut and
coconut which provides a
good store of energy for
germination.
Using Biuret test: which gives
mauve or purple or lilac colour.
Emulsion test ( ethanol
test):
Milky suspension.
Milk& dairy products
Meat, fish ,eggs,.
Legumes( peas& beans).
Soya beans & mycoprotein are both
used as substitute for meat.
1-saturated fats&
cholesterol: meat & animal
foods( egg, milk,cheese)
2- Unsaturated fats:(liquid):
Plant sources as sunflower
seeds& peanuts.
Fish as a good source of omega
3& 6
make proteins
028
28
I
t
Continue with -The main
nutrients( organic)
As we mentioned before that there are 4 main groups of organic chemicals used by living things:
1-carbohydrates ( compounds containing C,H,O)
2- Fats ( compounds containing C,H,O)
3- Proteins ( compounds containing C,H,O,N and sometimes Sulphur S)
4- Nuclei acids( compounds containing C,O,H,N and phosphorous P)
4- Nuclei acids ( C,H,O,N& P)
And structure of DNA
ab
r
( is the chemical that makes up our genes & chromosomes. Also it is the material we inherit from our parents, which gives
us many of our characteristics)
Organism
DNA
3.There may be millions of
nucleotides in a DNA molecule , but
there are only 4 different ones.
Some contain the base adenine(A),
some contain guanine(G), some
thymine(T), & some cytosine(C)
2.DNA is made up of
nucleotides. Where
each nucleotide
contains a base, and a
sugar phosphate
backbone.
Nitrogeno
us base
( A,T,C,G)
Dr
.N
4.The nucleotides form very
long ladder with bases as the
rungs of ladder.
The base pairs are always
one of the two types,Either
Adenine with thymine
Or guanine with cytosine.
Chromosome
iha
Cell
lG
1.DNA stands for
deoxyribonucleic
acid
A
G
T
Strand
2
Strand
1
C
6.The sequence of bases in a DNA molecule can
determine the order of amino acids in a protein
molecule, which determines the kind of proteins that
are made in our cells.
This, in turn , determines how our cells, tissue, organs
develop.
DNA as gene
Controls production of
Strand
1
Strand
2
Protein
5.Certain physical force causes
the ladder to twist around itself to
form a shape similar to a spiral,
called double helix
Dr. Nihal Gabr
Responsible for
Characteristic
029
29
It t
Continue with
4- Nuclei acids ( C,H,O,N& P)
A-Changing code words to amino acids
Gene
A sequence of bases (genetic information) that codes for a protein is called a gene.
In other words it is the length of DNA that is coding for a particular protein.
Each gene carries a series of code words for synthesis of proteins.
Each code word on DNA is made up of 3 bases ( 3 letters) in a
certain sequence.
Each code word is called a triplet, which corresponds to a single
amino acid in a protein.
ab
r
Genetic code
The code formed by the order of the bases in DNA that determines the organisms
characteristics ( by coding for specific proteins)
A DNA strand carries instructions in the form of
triplets =code words
Each triplet instructs the cell to build
one particular amino acid into a protein.
The four different bases in DNA ( adenine, thymine,
cytosine, guanine)
lG
C
G
That can be arranged in enough different triplets
T
G
iha
To code for all 20 amino acids normally found in a cell.
T
Where each protein molecule has hundreds, or even
thousands, of these 20 different amino acids joined
together in a unique sequence.
This gives each protein its own individual properties.
C
.N
T
G
T
Dr
G
G
Role of DNA:
1. Carries genetic codes
2. Codes for the protein to be made by cell
3. Carry genes to be inherited for offsprings.
Protein
A
Amino
acids
Bases
Summary
Controls
Controls
4.Function of
the protein
(Ex;enzyme)
ols
3.Shape of
protein
ntr
2.Sequence of
amino acids in a
protein
Controls
Co
1.Sequence of
bases in DNA
Controls
5.Metabolic
reactions in a
cell.
6.features of the
organism.
I030
t
30
Continue with
4- Nuclei acids ( C,H,O,N& P)
B-Protein synthesis
DNA is found in the nucleus.
Protein synthesis happens in the ribosomes in the cytoplasm.
So how does the code pass from the nucleus to the ribosome in the cytoplasm?
It is carried by another type of nucleic acid , called messenger RNA (mRNA)
Free amino
acids in
cytoplasm
2.
Protein assembled
from free amino acids
using base sequence in
mRNA.
tRNA
ab
r
mRNA leaves the
nucleus through a
hole in nuclear
membrane
DNA
Transfer RNA
bring amino acids
to the ribosome.
mRNA
lG
1.Transcription forming
mRNA inside the nucleus
A G U C A U G A C U A G A G U A CG
3.
iha
Translation
Where Ribosomes attach to the mRNA and the
instructions it carries are used to assemble
amino acids in the correct order to make a
specific protein.
Ribosome
3.Translation takes place in the
cytoplasm( in ribosomes):
the gene coding for the protein required, untwists
then unzips, the H-bonds between the strands
break
RNA nucleotides form complementary base pairs
with one strand of DNA bases
Then free RNA nucleotides join together.
Where the mRNA attaches to a ribosome.
Dr
.N
1&2.Transcription takes place in the
nucleus:
mRNA strand is synthesized
There is an important difference
between DNA replication and
RNA transcription.
RNA never contains the base
thymine(T). Instead its is replaced by a
fifth base called uracil(U)
So instead of the base pair A-T used in
DNA replication, in transcription we
have the base pair A-U
( if u have been eating a good diet full of enough
proteins, then the cytoplasm in your cells will
contain plenty of all 20 different amino acids).
As the long, thin mRNA molecule passes through
the ribosome, the ribosome links amino acids
together in exactly the right order to make the
desired protein, following the code contained on
mRNA molecule.
Summary
2.mRNA
1.DNA
3.Protein
Dr. Nihal Gabr
031
31
Effie
4.characteristics
B-Other 4 type of nutrients
Food source
Importance
Deficiency
Citrus fruit,
tomatoes&
vegtebales
Helps in formation of protein
collagen in skin, bones & blood
vessels thus:
1-strengthen blood vessels.
2- keep teeth and gum healthy.
3- protects cells from aging by
keeping skin healthy.
Scurvy
Pain in joints and muscles
Bleeding from gums and
other places.
Skin ulcers
Poor healing of wounds.
Butter, egg yolk,
fish liver oil.
Sunlight.
Helps calcium to be absorbed for
making bones and teeth.
Rickets in children
Bones become soft , bent
and deformed.
In adults
Osteomalacia( i.e fragile
bones)
Iron
Red meat, spinach
& liver
Formation of haemoglobin in Red
blood cells ,which carries
oxygen ,needed for respiration, to
all body cells.
Calcium
( cheese contain more
calcium than
milk??..)
Milk, dairy
products, bread
For bones, teeth, blood clotting.
6- Fibers (organic)
Indigestible part of
food ,the cellulose of
plant cells
Cereals grains.
Bread and
vegetables
Vitamin c ( water
soluble)
Destroyed by heating
and exposure to air
Vitamin D ( fat
soluble)
ab
r
4-vitamins(organic )
iha
lG
5-Minerals ( in
organic)
Dr. Nihal Gabr
Weak bones & teeth.
Poor clotting of blood.
Uncontrolled muscle
contractions(spams)
Rickets& osteomalacia.
Stimulate peristalsis of the intestine
to squeeze food along the gut.
Constipation & cancer
colon,as less fibers causes
less peristalsis.
1- Needed in Excretion, where
kidney removes away waste
product (urea) from body by
dissolving urea in water forming
urine.
2-Needed in Transportation, as
it makes blood plasma at which
substances as glucose& other
chemicals dissolve in it to be
transported all around your body.
3- Needed in Digestion, as it
causes hydrolysis of large insoluble
molecules into smaller soluble
molecules to be easily absorbed and
transported by blood.
4- cools down body
temperature.
5- important solvent, Needed for all
metabolic reactions which cant take
place unless chemicals which are
reacting are dissolved in water.
032
32
Its
Loss of 5% of body's water
can lead to
unconsciousness.
Increase in water loss,
causes increase in loss of
ions& salts,
dehydration( Diarrhoea)
.N
As a drink
In food especially
salad food
From aerobic
respiration.
Dr
7- Water( inorganic)
Important solvent in the
body forming about
70%of the human body
Anemia
Pale skin
Shortness of breath.
Feeling tired.
lG
ab
r
Food test.
.N
iha
Qualitative
test
Dr
Quantitative
test
Quantitative
test
Qualitative
test
Quantitative
test
From blue to green to yellow to
orange to red.
The faster the change in colour
from blue to red the higher the
conc. of reducing sugars.
The darker the purple
colour produced, the
higher the conc. Of
protein
Depth of colour can be
measured using a
colorimeter.
Igf
033
33
Milky white
emulsion
showing
presence of
lipids.
Balanced diet
Is a daily in take of the all nutrients in correct amounts according to body needs to
supply them with the right amount of energy needed for metabolism, which varies
Dr
.N
iha
lG
ab
r
according to age, sex and physical activity.
Growth: permanent increase in number and or
size of cells ( = to increase in dry mass)
Dr. Nihal Gabr
034
34
-8-6
Tips for
answering
questions
Mal nutrition
Mal nutrition
Not eating a balanced diet:
1- eating too much of food.( over
nutrition)
2- Having to little food( undernutrition)
3-Eating too much or too little of a
particular nutrient.
Over nutrition
Under nutrition
Obeisty
ab
r
Starvation
Deficiency
disease
Other
complications
m.iq
lG
1- Excess sugar causes
tooth decay.
2- Excess salt causes
increase in blood
pressure.
3- Excess fat causing
artheriscelorisis.
The body starts
breaking down
carbohydrates,
then fats and
finally proteins
Resulting in small
weak shrinked
muscles and
bones cant grow.
2- calcium & vitamin D
deficiency:
Symptoms:
Rickets in children, and
osteomalacia (fragile
bones) in adult.
More symptoms in Calcium
deficiency is week bones and
teeth, uncontrolled muscle
contraction&poor clotting of
blood.
3- iron defeciency:
Dr
Obesity increases the risk of:
1-Heart disease (CHD) as fat deposits on
the walls of coronary arteries making
them stiffer and narrower, so the heart
muscle run short of oxygen & glucose
so cant respire normally.
2- Heart attack also resulting from
deposition of fat in arteries causing
blood clot.
3- Physiological disturbances from the
unattractive shape.
4- Diabetes "high blood sugar level".
5- High blood pressure.
Symptoms:
Anaemia (pale skin,
shortness of breath &
lack of activity)
•☆→E&•
4-Protein energy
malnutrition:
Kwashiorkor
How to avoid obeisty:
Decrease intake of fats
and carbohydrates.
Regular exercise to
increase food burning.
Eating more
fibres( rouphages).
Dr. Nihal Gabr
Dr. Nihal
Gabr
1- vitamin C deficiency:
Scurvy:
Symptoms:
Pain n joints, bleeding
from gums& falling teeth,
Skin ulcers& poor
healing of wounds.
.N
iha
=Over weight
A condition in which fat
storage is beyond
healthy limit, resulting
from eating too much
fats& carbohydrates.
Not eating
enough food
over a long
period of time.
In which the child is forced on a
diet too high in carbohydrates
and nearly no proteins.
Symptoms: shrinked muscles ,
swollen belly(abdomen)&
swollen liver because its
working too hard to make
proteins needed by body from in
adequate dietary supply.
035
35
Marasmus
No Protein nor enough
'energy food '
Symptoms:
All body tissues waste away
and child become very thin
with wrinkled skin.
B-Digestion
The alimentary canal (gut) of mammals is a specialised tube running from the
front of the animal ( starting at mouth) to the rear ( ending at its anus) .
Ingestion
The digestive system: includes the alimentary canal ,liver & pancreas.
ab
r
Taking in of substances as food&drinks,
into the alimentary canal through mouth
Dr
.N
Passing out of food that has not been
digested, nor absorbed, as faeces
through the anus
Egestion
iha
The movement of small soluble molecules
& ions through the walls of the small
intestine( ileum) into blood.
Absorption
lG
Digestion
Break down of large insoluble food
molecules into smaller soluble ones that
can be absorbed into blood.
The movement of digested food
molecules into the cells of body
where they are used, becoming
part if the cell.
1Mechanical:
Assimilation
1st:Types of digestion
Ex: muscle cells use amino acids to
make proteins.
2- Bone cells take up calcium&
phosphate to make bone.
3- All cells uses glucose to release
energy by respiration.
Break down of food into smaller pieces without chemical change to the food
molecules, to increase the surface area for chemical digestion.
Next
page
Dr. Nihal Gabr
Example:
1- Teeth: bite, chop& grind food into smaller pieces.
2- Stomach: churning food by contraction& relaxation of stomach muscles forming chyme.
3- Emulsification: breaking down of large fat droplets into smaller ones by bile salts in bile juice..
036
36
f-
2Chemical:
Break down of large insoluble molecules into small soluble ones by
using enzymes ,including break down of bonds(hydrolysis)
Nutrient( substrate)
Enzyme that breaks it down
Small molecule produced
Starch
Amylase ( carbohydrase)
Simple sugars
Proteins
Protease
Amino acids
Fats
Lipase
Fatty acids & glycerol.
Remember APL
1- Mouth
Bite & grind food into smaller pieces to be easily
swallowed& increases surface area for chemical
digestion by enzymes.
lG
1-Teeth
ab
r
2nd: steps of digestion
Produces
saliva
which is a
mixture
of:
2-Mucus
.N
2salivary
glands
Dr
2-
1.
Helps in hydrolysis ( digestion) of large molecules
into smaller ones .
2. Act as a solvent for nutrients& enzymes to dissolve
in.
3. Soften food making it easier for food to be chewed,
swallowed& move along the alimentary canal.
iha
1-Water
3-Amylase
oesophagus
Circular muscle
contracts*
Peristalsis
Longitudinal muscle
relax*
1. Make chewed food in mouth bind together to form
bolus.
2. Lubricates food making it easier to move down the
alimentary canal.
3. Also forms a covering over the inner surface of the
alimentary canal preventing enzymes& acidic
juices in stomach from digesting cells.
Digest starch in food into sugar maltose( disaccharide)
Waves of contraction & relaxation of muscle walls of
alimentary canal for squeezing and pushing the food forward.
( circular& longitudinal muscles work antagonistically , one
contract& the other relax to push food forward)
Food moves by peristalsis:
1- bolus pushed down oesophagus.
2- food in small intestine.
Why is fibre important in human
diet?
1- stimulates peristalsis.
2- Reducing risk of constipation.
3- Reducing risk of colon cancer.
Circular muscle
relaxes
Bolus
Dr. Nihal Gabr
037
37
f-
Cardiac sphincter: relaxes to
allow food enter stomach
3-Stomach
Pyloric sphincter: relaxes to
allow food enter small intestine
1-Muscular walls
of Stomach
1.
2-Gastric juice
Produced from pits in the walls of stomach& it contains:
1-Protease(*pepsin): which breaks down proteins into polypeptides *working best
in acidic conditions.
2- Hydrochloric acid:
Provides acidic conditions needed for action of protease( pepsin)
Kills any bacteria in food by denaturing its enzymes.
3-Mucus
Secreted from goblet cells in walls of stomach.
( function: as in mouth)
1Duodenum
Main function: .1- emulsification of fat
2- change pH of food coming from stomach from pH 2 to about PH 9
Produced from
liver.stored in gall
bladder, and enter
into duodenum
through bile duct.
1- Bile
salts*
Causes emulsification of large fat
globules into smaller droplets,
giving a greater surface area to
be easily digested by lipase into
fatty acids& glycerol.
iha
1.
Duodenum
.N
1 Bile
juice
Notice-1- its about 5 m long.
2-most of water is reabsorbed from small intestine.
Notice
lG
4-Small intestine
ab
r
Strong muscular walls that contract& relax to churn food& mix it with enzymes
& mucus forming chyme.
2- Bile
pigments*
Dr
Aorta
Hepatic artery
Gall bladder
2Pancrea
tic juice
Hepatic
portal vein
Produced in the
pancreas and enters
duodenum through
pancreatic duct.
Made from breaking down of old
RBCs in liver and act as an
execratory product that leaves the
body through faeces.
3Hydrogen
carbonate
It is an alkali that helps neutralise
acid( chyme) coming from stomach.
1Hydrogen
carbonate
Reduces acidity of Chyme.
2amylase
Breaks carbohydrates into maltose
3Protease*(
Breaks proteins into polypeptides*
4-lipase
Breaks fats into fatty acids and
glycerol.
Ileum
trypsin)
Dr. Nihal Gabr
038
38
f-
Main function: .1- complete digestion of all food types.
2- Absorption of digested food
2- ileum
Adaptation*:
A- very long and coiled with folded inner lining with finger like projections( villi) to provide large surface area
for faster rate of absorption.
B- Has villi :
1-Each villus is covered with cells ,epithelium cells,which are only one cell thick for shorter distance of
ab
r
diffusion of digested food molecules
2-epithelium cells have even smaller projections on them called microvilli, giving a larger surface area for
faster rate of absorption by diffusion or active transport.
3-capillaries: rich in blood supply for to transport quickly glucose, amino acids, water, minerals&
vitamins to the liver( through hepatic portal vein) then around the body.
4- epithelium cells of their wall have lots of mitochondria to provide energy needed for active
transport( through respiration).
5-lacteal: transports fatty acids and glycerol through lymphatic system.
6- Goblet cells: that produce mucus to protect the lining against digestion by body's own enzymes.
+
Single villus
Remember:
Villi( finger like
projections)
.N
iha
lG
Small intestine has a
peristaltic action in
which its walls contract
to increase absorption.
Enzymes made by
cells covering villi:
1. Breaks down maltose into glucose( monosaccharide)
2-*peptidase
Breaks down polypeptides* into amino acids.
3-Lipase
Breaks down fats into fatty acids& glycerol.
Dr
1carbohydrase(Mal
tase)*
5-large intestine
Large intestine
includes:
1-Colon
1. More water and salts are reabsorbed
2-Rectum
Ores faeces( formed of indigestible food as fibers, bacteria& some dead
cells from inside of alimentary canal).
3-Anus
Egestion of undigested food as faeces
Dr. Nihal Gabr
039
39
g-
3rd: Summary
Juices
secreted
Components of juice
Part of production
Saliva( Mouth)
Salivary glands
1-Amylase
Function
Breaks carbohydrates into
maltose
2- soften food to form
Bolus
From walls of stomach
1- protease*(pepsin)
Breaks down proteins into
polypeptides.
ab
r
Gastric
juice(stomach)
From liver, stored in gall
bladder.( its alkaline helping
to neutralise acid coming
from stomach)
1- bile salts
iha
Bile
juice( duodenum)
lG
2-hydrochloric acid(HCl)
From pancrease
Dr
Pancreatic
juice( duodenum)
.N
2- bile pigments made from
breaking down of dead
RBC in liver
1- kill any bacteria entering with
food.
2-provides acidic pH suitable for
protease activity.
Emulsification of large fat droplets
into smaller droplets to be easily
digested by lipase
Excretory product that leaves the
body with faeces.
1-amylase:
Breaks carbohydrates into
maltose.
2-protease*(trypsin)
Breaks proteins into polypeptides
3-lipase
Breaks fats into fatty acids
&glycerol.
4-sodium hydrogen
carbonate
Reduces acidity of chyme.
All the digestive juices contain water and mucus:
Water: 1-used for digestion of large molecules into smaller ones
2-Also a solvent for the nutrients and enzymes to dissolve in.
Mucus:1- lubricant
2-Also forms a covering over the inner surface of the alimentary canal, preventing enzymes
from digesting the cells.
Dr. Nihal Gabr
s
040
of
40
New syllabus
Wall of
alimentary
canal
*
Dr
.N
iha
lG
ab
r
4th:
Wall of
alimentary
canal
Lumen
Blood
capillary
5Cholera
bacteria
ClH 2O
1.
2.
3.
4.
Cholera bacteria are ingested and start to multiply in the small intestine.
The bacteria attache to the wall of the alimentary canal.
The bacteria releases toxins.
The toxin stimulates the lining of the intestine to secrete chloride ions, which
accumulate in the lumen of the small intestine.
5. This increases the concentration of the fluid in the lumen, lowering the water
potential.
6. So water will move out of blood into the lumen of small intestine by osmosis.
7. There is now a lot of water in the canal ( watery diarrhoea) , so large quantities
of water will be lost from the body in the watery faeces.
However, as long as this lost fluid is replaced ,
almost every person suffering from cholera will
eventually recover.
041
41
A-TEAM
Dr. Nihal Gabr
042
42
If
Blood contains variable
and possibly dangerous
high concentration of
food molecules( ex:
glucose& amino acids),
depending on what has
been absorbed from gut.
Deoxygenated blood
from small intestine
enters the liver
through hepatic
portal vein
Dr
4
Ds
ab
r
lG
Ex: muscle cells use amino acids to make proteins.
2- Bone cells take up calcium& phosphate to make bone.
3- All cells uses glucose to release energy by respiration.
Liver's role in assimilation
Blood contains oxygen
needed for aerobic
respiration to release
energy needed by
biochemical reactions in
liver.
Oxygenated blood
enters the liver
through hepatic
artery
iha
.N
Blood contains a
constant & ideal
concentration of food
molecules such as
glucose& amino acids.
Deoxygenated blood
leaves the liver to return
to general circulation
through hepatic vein.
4 Ds
5th: liver function & Assimilation
A-Teeth structure
6th: Human Teeth
In each jaw there are 16 teeth( total 32 in both).
There are four types of teeth in human (four incisors, Two canines, four
premolars and six molars), each specialised for different functions.
Canine
Premolar
ab
r
Incisor
Front
Either
sides of
incisors
Behind
canine
:Descript
ion
Chisel
shaped
with sharp
edge
Slightly
more
Pointed
than
incisors
Broad
broad
with 2 or 3 with 4or 5
cusps
cusps
Function
Cutting &
bitting
Holding
and
tearing of
food
iha
lG
Position
in mouth
.N
Dr
Cement
Molar
Back
Crushing , grinding&
chewing of food.
1-Enamel : 1-hardest tissue in the body which is very
difficult to break,
2-But can be dissolved by acids produced by bacteria when
it feeds on sugary food left on teeth.
3- made of calcium salts.
4- Enamel can't be renewed or extended.
2-Dentine : 1-less hard than enamel ( but harder than
a bone)
2it has channels containing cytoplasm.
3- made of calcium salts.
3-Pulp cavity : 1-contains blood vessels to supply
the cytoplasm in dentine with food and oxygen.
2- contain nerve endings which detect pain.
4- Cement-: covers the root
1- has fibres growing out of it which attach the
tooth to the jaw bone,, but allow it to move slightly
when bitting or chewing.
5- gum: covers the junction between
enamel and cement.
Dr. Nihal Gabr
043
43
e-
Longitudinal section of an incisor
Front view
Crown
Pulp cavity
Gum
Cement
Root
Incisors
Premolar
Canine
Molar
lG
Fibres
attaching
tooth to jaw
bone
Side view
ab
r
Dentine
Other Figures for teeth that you might
find useful
Enamel
'Fecf-÷_÷--T_gtf÷[
B-Dental decay
Dr
.N
First: Gum disease
iha
Caused by bacteria.
1- food remains+
bacteria+ mucus
from saliva) =
form plaque
which builds up
around the edges
of teeth and
gums.
2- if the plaque is
left it hardens
forming
tartar,now the
bacteria may
work down
around the roots
of tooth.
Symptoms at
stage 1The gum swells ,
become inflamed,
and may bleed
when you brush
your
teeth( painless)
Dr. Nihal Gabr
3-The tooth is
loosened and
may fallout
or have to be
removed .
Symptoms at
stage 3Tooth loosen
Inflamed gum and loosening of
tooth may be caused by deficiency
of vitamin C
044
44
-8g
Second: Tooth decay
1- particles of sugary food is
trapped in cracks in teeth.
2-bacteria in plaque(..)will use
this sugar to respire producing
acid,which dissolves calcium in
enamel then into dentine.
3-dentine dissolves more
rapidly than enamel, then it
reaches pulp cavity where there
are nerves so sever toothache
4- the bacterial infection in
pulp may lead to formation of
abscess at the base of
tooth( sever pain)
Plant nutrition
Topic 6
:
:?
:
.: :
Plant nutrition
.
?
.:
?
:
: is the process by which the plant make
carbohydrates( organic substance) from carbon dioxide and water( inorganic
substances) using energy from light.
Carbon dioxide+ water
( 6 CO2 + 6 H2O
.
.
Petiole or leaf
stalk
:
.
:
.
Midrib
Leaf
blade( lamina)
iha
lG
Important for practical
part( paper 6)
:
Glucose+ oxygen.
C6H12O6+ 6O2)
ab
r
.
Light energy
( chlorophyll)
Vein
.N
Labelling and
function of each part is
important)
Dr
Small netted
veins
Thick walled
Thin walled
Dr. Nihal Gabr
046
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Vein(branches of
Vascular bundles),
running through
mesophyll layer
Plant nutrition
Parts of
leaf
Function
1-cuticle
1-waxy material that prevents water evaporation from leaf.( impermeable to water,
thus decreasing transpiration)
2- Protect the inner surface of leaf by preventing the entry of disease causing
organisms( ex: bacteria/ fungi).
3- Transparent with no chloroplast to allow passage of light to inner layers of leaf
2- upper
epidermis
1- Single layer of cells, secreting waxy cuticle
2- Act as a barrier against bacteria & fungi.
3- Transparent with no chloroplast to allow passage of light to inner layers of leaf.
-Palisade
mesophyll
1- Tall thin cells arranged in columns, end on to keep as few cell walls as possible
between sunlight and chloroplast.
2- packed with chloroplast arranged broad side on to absorb as much sunlight
as possible.
ab
r
3-Mesophyll
layer( meso
= middle,
phyll= leaf)
But in strong sunlight they arrange themselves end on to reduce amount of light absorbed.
Chloroplast
arranged end
on
lG
Chloroplast
arranged
broad side on
iha
3- cells arranged close together with tiny airspaces, to absorb as much light energy
as possible.
4- Chlorophyll arranged on flat membrane inside chloroplast, to expose as much
chlorophyll as possible to sunlight.
.N
Starch grains where
starch is stored
Membrane that
contains chlorophyll
molecules that can trap
light energy.
Dr
Membrane
around
chloroplast
-Spongy
mesophyll
1- Contain chloroplast to absorb light energy for photosynthesis.
2- cells are rounded&loosely packed with large air spaces to allow easier diffusion of
gases through leaf.
3- air spaces are saturated with water vapour to allow diffusion of water out of leaf
Down concentration gradient ( transpiration)
4- cells are covered with a layer of water where carbon dioxide dissolves and diffuse
through cell wall/ cell membrane.
Air spaces are
saturated with water
vapour.
Dr. Nihal Gabr
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46
ITS
Spongy mesophyll cells
are covered with a thin
layer of water.
Plant nutrition
5- Stomata
Stoma( single)
Opening To allow carbon dioxide to diffuse in and oxygen out.
6- Guard cells
Present in pairs surrounding a stoma( hole).
Unlike other cells in the epidermis,they contain chloroplast and control the opening
and closing of stoma for :
1-gaseous exchange,
2-controlling transpiration.
Guard cells
( swollen/ turgid)
-Xylem
vessels
with thick lignified walls to transport water and mineral salts to cells in the leaf
phloem
tubes
With thin wall to carry away sucrose and other organic products that the leaf has
made.
lG
7-vein(vascular
bundle)
Stoma closed
When the plant is
short of water
ab
r
when plant has
Thick cell
plenty of water,
wall
The cell wall on the
inner surface is very
thick ,so it can't
stretch as much as
the outer surface.
Thin cell
So as the guard cells
wall
swell up, they curve
away from each
Stoma open
other, opening the
When plant has
stoma.
plenty of water
Guard cells
( shrunken/ flaccid)
Describing Photosynthesis:
1- carbon dioxide diffuses through stomata in leaf.
2- water absorbed from soil by roots, moves up to stem through xylem vessels to leaf by Osmosis.
3-Chlorophyll in chloroplast absorbs/traps light energy.
Where light energy makes carbon dioxide combine with water( with the help of enzymes) to make
glucose ( organic compound).
Now light energy is converted into chemical energy stored in glucose
4- oxygen is released.
.N
Dr
Water
CO2
Oxygen
Hydrogen
Glucose
iha
I'm
1.Light energy is
trapped by chlorophyll
molecules.
4. Oxygen is released
5. CO2 diffused through stomata then
through air spaces then through cell
wall& cell membrane to chloroplast.
2. Water molecules brought from
roots up through the xylem
vessels to mesophyll cells then to
chloroplast by osmosis.
7. Part of Glucose is stored as
starch grans
3. Light reaction
Where light energy splits the water
into hydrogen & O2.
6. Dark reaction
Hydrogen and CO2 react to form glucose
this reaction is catalysed by enzymes.
! Chloroplast containing chlorophyll.
( site of photosynthesis)
Dr. Nihal Gabr
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47
Its
Plant nutrition
:
.
:?
.: :
Dr
.N
iha
lG
ab
r
.
2
CO2 diffuses
through air
spaces then
through cell
wall& cell
membrane to
chloroplast
CO2 diffuses
through stomata
If amount of CO2 taken at day=amount of CO2
released at night by respiration so,
No sufficient photosynthesis
No food supply( no glucose)
Not enough for growth & energy supply.
Dr. Nihal Gabr
Sunlight
1
049
48
Tts
2
Water travels to
chloroplast by
osmosis
Water is
brought from
roots in xylem
vessels
1
Plant nutrition
(
:?
.
.: :
. :.:
:.
.
?
?
Dr
.N
iha
lG
ab
r
Remember:
Plant obtains CO2 for
photosynthesis by:
1)- diffusion through stomata
down concentration gradient,
through air spaces where it
will dissolve in water and
diffuse through cell wall and
cell membrane.
2)- in mitochondria from
respiration.
Fate of glucose( over all)
1- used in respiration to release energy.
2- changed to starch for storage.
3- changed to cellulose to form cell wall.
4- changed to sucrose to be translocated to other parts of plant.
5- changed to amino acids(by combining with nitrogen) needed to form
protein for growth.
6- forms oil stored in seed.
{
7. Used to make nectar to attract pollinators.
Stored in fruit to attract animals.
Dr. Nihal Gabr
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49
Importance of
glucose in
pollination and
seed dispersal.
Plant nutrition
)
.
.
:
.
.
:?
.: :
1-light intensity
2- Carbon dioxide concentration
3- Temperature:
- As temperature affects the enzymes that catalyse the chemical reactions of photosynthesis.
- and affects opening and closing of stomata (if weather is very hot, stomata close to prevent to
lG
ab
r
much water loss, thus allowing lessCO2 can diffuse in , so photosynthesis slow down.).
Is an environmental factor being internal/ external as ( CO2, light, temp.) present in
a short supply that limits rate of a reaction (as photosynthesis/Growth)
A is the rate limiting factor
.N
Rate of
photosynthesis
iha
Limiting factor
{
{
A second factor has become limiting
Dr
Here the value
of factor A is
controlling the
rate of
photosynthesi
s:
A is the
limiting factor.
Here increase in the light intensity
doesn't increase rate of
photosynthesis: there is some other
limiting factor
Availability of factor A
For plants to grow in large numbers/ at high rate? They should be provided with the
following:
1- Fewer limiting factor in their habitat.( CO2, light intensity)
2- Controlling a suitable temperature to avoid plant over heating that might cause enzymatic denaturing.
So- higher rate of photosynthesis.
So- more food (starch) for growth.
3- No animals to feed on it.
4- More fertile soil by adding more minerals.
5- no disease.
Dr. Nihal Gabr
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50
•
Solution
Plant nutrition
Growing plants in glasshouses ( green house)
Factors controlled in green house to give high yield of crop:
1.Thermostat for controlling temperature.
2. Controlling & reducing effect of limiting factors by:
" providing artificial light source when light intensity is low.
" providing shade when light intensity is too high.
" temperature control by cooling & good ventilation.
" CO2 enrichment using bicarbonate HCO3-.
ab
r
" controlling humidity by ventilation.
3. Using fertilsers to provide required minerals.
4. Easier to control pests , disease and weeds.
?
: ..
iha
lG
Importance of ventilating green house:
1-to decrease temperature on hot days.
Thus avoiding denaturing of enzymes.
and avoid plant wilting
by excessive transpiration.
2-Allow carbon dioxide to enter during the day .
3- Allow oxygen to enter during night.
.Thus allowing plant to respire
4- Allow water vapour to escape to surrounding , to avoid air becoming too humid.
5- Reducing chance of fungal infection.
.
.:
:
.
:
:
.N
Plants need minerals for healthy growth. They are absorbed through the roots
by active transport as mineral ions dissolved in the soil water.
Element
Nitrate
N( Nitrogen)
Importance
Dr
Mineral
Ions
Deficiency
1.Needed to make amino acids required to make
1- poor growth/stunt
" proteins as enzymes, cell wall, membrane,
growth.
cytoplasm for plant growth.
" chlorophyll .
2.Needed to make nucleic acids (DNA).
2- Smaller/ fewer
leaves
3- Pale yellow leaves
4- stem is thin
5- shorter root.
Magnesiu
Mg( magnesium)
m ions
Needed to make chlorophyll
1- yellow leaves
Which is needed for photosynthesis by
( yellowing between
absorption of light to make glucose( organic
veins of leaves).
compound), which is needed for.................
2-will die as no
photosynthesis so no
growth.
Dr. Nihal Gabr
052
f51
Continue with
minerals &
increasing soil
fertility
Plant nutrition
How to increase soil fertility:
Linked to human influence and
1.adding artificial fertilisers
food production.
2.Using animal manure (sewage sludge)which is not easily leached.
3. using humus which prevents soil erosion.
4. Growing leguminous plants to allow growth of nodular bacteria that makes nitrogen fixation
Ex: clover, peas, beans.
5. Allow soil aeration.
6. Allow mixed crop rotation to prevent the removal of some nutrients specifically from soil.
ab
r
Excessive use of fertilisers
causes eutrophication
Excessive fertilisers drain into nearby rivers
lG
Boosts growth of algae on the lakes' surface
This blocks light from reaching plants below the surface, so no photosynthesis.
iha
Plants die.
Aerobic Bacteria decompose dead plants using O2 dissolved in water
Dr
.N
Anaerobic conditions( lack of O2) in water causes death of aquatic life
Dr. Nihal Gabr
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Plant nutrition
1
Linked paper 6
M/J 2012 p61(q
1b,c,d,e)
Boiling
water
ab
r
Ethanol
2
Using microscope
to observe cells in
leaf
.N
Adding iodine solution
iha
lG
Warm
water
Dr
How to determine the number of stomata
present on one surface of a whole leaf?
1.
Use a microscope for magnification.
2.
Peel off the epidermal layer/ or paint the leaf
surface with nail polish then allow it to dry, then
tap a piece of cellophane tape to the dried nail
polish, then gently peel the tape
Now you have a leaf impression which you will
examine by putting it on a slide and add drops of
water then add coverslip.
3. Count the number of stomata in this area of leaf
4. Determine the area seen under microscope using
a ruler in eye piece.
5. Calculate the total surface area of leaf using a
graph paper.
Dr. Nihal Gabr
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53
-8
1.
2.
3.
4.
5.
6.
O/N 2007 p6 (2d)
M/J 2011 p61 ( 3c)
How you would prepare a
microscope slide of the cells of a
plant stem/root to show starch
grains?
Use a microscope for magnification.
Cut thin layer in the plant root/stem
and remove using forceps.
Place on a microscopic slide.
Stain with iodine.
Cover slip is added.
Look for blue stained grains .
Plant nutrition
3
E
F
ab
r
D
lG
B
A
iha
C
Second:
B
A
.N
Air sealed bag
(1)-Soda lime
which absorbs
CO2
Dr
Black
paper
clipped
onto
both
sides of
the leaf.
(2)-Hydrogen
carbonate
solution which
releases CO2
The same apparatus can be used to carry out
the three investigations but each time have only
one changing variable( input) and keep other
variables constant as shown in the table below
in next page..
C
White
Variegated leaf
Next
page
A
B
C
Third:
Testing for starch
using Iodine test
Dr. Nihal Gabr
(1)(2)
055
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Plant nutrition
Input( independent
variable)
Outcome( dependent
variable)
Constant( controlled variables)
=
1- Different
light
intensity
Use electric lamp with
different light intensities
1- Temperature using
water bath or thermostat.
2- concentration of carbon
dioxide.
2-Different CO2
concentrations
Add different amount of
sodium hydrogen
carbonate to water.
3- Different
temperature
Stand the apparatus in
water bath kept at
different temperatures.
Volume of Oxygen gas
released.
Ways of its measurement:
1- using a gas syringe to
measure the volume of
oxygen gas in a fixed
length of time
2- Using oil droplet scale
to measure the volume of
O2 in a fixed length of
time.
3- counting number of
bubbles in a fixed length
of time.
1- light intensity using
same lamp kept at same
distance.
2- same temperature
3-Same
plant
species
with
same
number
of
leaves.
1-same light intensity.
2- same concentration of
CO2
O/N 2008 p6( q 2)
O/N 2009 p6 (q3)
M/J 2010 p61( q3)
O/N 2014 p61 (q3)
M/J 2015 p61 ( 1c)
lG
Steps to
plan an
investigation
ab
r
Investigation
rate of photosynthesis)
iha
1- Write the hypothesis that you tested( ex: investigating that different light intensity affects
2 - use the independent variable ( input) and settle your experiment( I.e state the apparatus
.N
used with description of your method)
3-set all the constant variables. Same....... For fairness.
Dr
4- set a time interval for your experiment.
5- set a way for measurement of the outcome over the time interval
6- Draw a headed table of results including mean if there is repetition.
7- Draw a headed (line) graph for your results.
8- a conclusion( ex: increase in light intensity increased rate of photosynthesis).
9- you may write an explanation( ex: light is needed in photosynthesis to help reaction between
CO2 & water to form glucose)
10- for reliability: repeat your experiment :
Using larger sample/ over longer interval of time :
A-take an average to reduce errors.
B- exclude all anomalous results.
Dr. Nihal Gabr
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•
Plant nutrition
You might be asked to set a control..
Whats a control and how to set it??
Control: Is carrying out the same experiment but without the input,
Why use a control? To show that the factor under test is responsible for the change
observed/ to compare the effect of variable being measured.
Investigation
Control for the experiment.
Part of leaf covered with black paper
B-importance of carbon dioxide for photo.
Leaf covered with soda lime( potassium hydroxide)
which absorbs carbon dioxide.
C- Different Importance of chlorophyll for
photo.
The white part of the leaf is the control.
D- effect of different light intensity on rate of
photo.
Repeat the same experiment with boiled plant or put it in
dark.
E- to show that oxygen is produced in
photosynthesis.
Same apparatus but with boiled or no plant
lG
F- effect of different catalase enzyme( in seed)
on amount of oxygen gas produced.
Same apparatus using boiled seed/ enzyme/ fruit.
iha
Show that O2 is
produced during
photosynthesis.
.N
4
ab
r
A-importance of light for photo.
1.
2.
Set up the apparatus shown in the diagram.
Making sure that the test tube is completely full of water.
Dr
Leave the apparatus near a warm, sunny window for 2 days.
3.
4. Carefully remove test tube from top of the funnel allowing water to
run out but not allowing the gas to escape.
5. Light a wooden splint, and then blow it out so that it is just glowing.
Carefully put it into the test tube. If it bursts into flame ,then the gas is
oxygen.
What you should
Notice from this
investigation.
1. How to text for oxygen.
2. The investigation is done under water to allow O2 (gas) to be collected over water, as when a gas is
produced at top of tube filled with water, this creates pressure to force water down the tube( water
displacement).
3. If you want to set a control for this experiment , carry same experiment but with no plant/ with boiled
plant.
Dr. Nihal Gabr
•
057
56
Topic7
Transport in plants
Plant has two transport system:
Xylem vessels
Phloem tubes
ab
r
Transvers
e section
Lignified cell wall
Companion cell,
containing a nucleus
and dense cytoplasm
Space containing no
cytoplasm
Gap where end wall
of cell has been lost
Phloem
tissue
( living tissue)
Cell wall containing
cellulose but no lignin
Sieve tubes containing
strands of cytoplasm,
but no nucleus.
Sieve plate with pores to
allow passage of sugar
from one cell to the next.
.N
Longitudinal
section
Function
Adaptation
1-Transport water and
dissolved mineral ions from
root up the stem to leaves.
1-They are made of dead cells , with no nucleus and no
cytoplasm so water& mineral ions can pass freely.
2-No end walls so that many cells form a continuous tube.
3-They run from roots right up through stem to leaves
2-support the stem
1-They have thick cell wall containing lignin which is
waterproof and help resist strains by wind.
1-Translocate( transport)
sucrose and amino acids
dissolved in sap solution
from region of production to
region of storage or
utilisation( respiration &
growth)
1-Formed of sieve tubes which has thin layer of
cytoplasm( as the cell must stay alive or else sugar transport
will stop) but no nucleus or organelles so sugar flow is not
impeded.
2-Pores in sieve plates through which sugar pass from one
cell to next.
3-Companion cell doesn't transport sugar but carryout some
life processes of sieve tubes.
Dr
Xylem tissue
( dead tissue)
iha
Longitudinal
section
lG
Thin area of cell
wall called pit
Dr. Nihal Gabr
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A group of xylem vessels and phloem tubes is called vascular bundle.
The positions of vascular bundle in root ,leaf& shoot of a dicotyledon Plant are
show in the following figures
Linked paper 6
Cortex( act
Xylem
Cambium
Xylem
Cambium
Cortex( cells
become turgid
to help support
plant))
Phloem
Vascular bundles in
leaf
Vascular bundles in Stem
Arranged in a ring near the
outside edge
Vascular bundles in
Root
ab
r
Root hair
extended cells
of epidermis
increase
surface area
for water&
ion uptake.
Xylem
as a winter
store for
starch)
Phloem
Phloem
lG
Found at the center
First: water uptake
.N
Linked to movement in
and out of cells&
Specialised cells
iha
Xylem +phloem+ cambium=
vascular bundle
Dr
1- Water enters the root hair
cells by osmosis down the
water potential gradient.
2- Water crosses the living
cells of the cortex by
osmosis.
The root hair select which ions can enter from the
soil using active transport against concentration
gradient using energy from respiration.
As
059
58
3-water is pulled up the
xylem to replace water lost
at leaves( transpiration
stream)
Second: Transport of water &
Transpiration
Water movement through a plant begins with diffusion of water vapour out of the leaf and
evaporation from the leaf surface( spongy mesophyll). 98% of water taken up by a plant is lost to
the atmosphere by transpiration to help cool down the plant in hot weather.
Definition
1-Transpiration:
• loss of water from plant leaf
• By evaporation of water at the surface of spongy mesophyll
cells,
• Followed by diffusion of water vapour through stomata, down
concentration gradient.
{
2
2-Water moves from xylem:
• To enter leaf tissue down water
potential.
ab
r
1
3- Water moves up in the stem in the xylem by:
1- transpiration pull ( which reduces the water
pressure at the top of the vessel while at the bottom the
pressure stays high).
• Which is maintained by cohesion between
water molecules forming water column.
• And adhesion of water to walls of xylem vessels.
2-capillarity
4- Water uptake:
• Occurs by osmosis from soil solution( high
water potential) into root hair cells( lower
water potential) down the concentration
gradient.
Dr
.N
4
iha
lG
3
060
-8
59
Third: importance of water in plant
If the plant loses too much water so that cells of its
leaves become flaccid& plant wilts, this might
happen due to :
1- Rate of transpiration is higher than rate of
water uptake( in hot weather or strong wind).
2- when plant is placed in a salty soil, so that
concentration of water in cell sap is higher
than the soil, so water diffuses from inside
cells to outside down water potential by
osmosis.
The plant needs water for:
1-prevent wilting and maintain cell
turgidity.
2- Transport of minerals.
3- medium for enzymatic activity.
4- raw material for photosynthesis.
.N
Dr
Dr. Nihal Gabr
061
60
By
Next page
iha
lG
ab
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Fourth: investigation of
transpiration.
Air/ water
bubble :
movement
Reservoir corresponds
of water.
to water
uptake by the
cut shoot.
ab
r
Air/ water graduated
scale to read the bubble
movement( water uptake)
lG
Procedure:
1- shoot fixed to potometer with no air gaps
using petroleum jelly.
2-fill the apparatus with water using the
reservoir.
3- close clip of reservoir and leave the apparatus
in light.(...........)
4- as plant transpires ,the water lost is replaced
by water it takes up the stem, where air bubble
starts to move along the scale.
5-measure rate of bubble movement at least
three times and use reservoir to return bubble to
zero each time. Calculate mean of reading.
iha
This method doesn't give you a
good measurement of rate of
transpiration because...the
potometer actually measures
rate of uptake of water not rate
of loss,as not all water taken by
plant is lost in transpiration...
1
.N
2
3
Why not all water up taken by plant is removed by Transpiration??
Dr
1- part used as a raw material for photosynthesis.
2- part needed for turgidity and support.
3- part needed for transport of solutes( food substances)
4- part takes part in chemical reactions( hydrolysis& breaking down of food substances.
5- medium for chemical and enzymatic reactions.
Fifth: Translocation
Translocation:
Is the transport of sucrose and amino acids ,dissolved in sap solution to move through phloem
tubes by active transport/ Diffusion ,
from region of production(source) or absorption....... to regions of utilization in
respiration and growth( ex: buds, small leaves, flowers) or to regions of storage as roots or
stem ( sink).
Dr. Nihal Gabr
062
61
-
Transport system in plants
Leaves:
Are both sinks& source.
Fruit:
• Need water for swelling of ovary wall if
succulent.
• Need sucrose to be converted into starch as
any energy storage.
Flower:
• Need sucrose to form nectar ( fructose).
Growing points:
• Need water for swelling.
• Need sucrose as energy source for cell
division.
• Need all nutrients as raw material for cell
production( as making cellulose,....)
ab
r
Source:
• Glucose formed
from
photosynthesis,
which is
condensed into
sucrose
To be translocated
through phloem to
sink.
Water with dissolved ions
move always up the stem
• Water as a
reactant in
photosynthesis.
• Magnesium as a
component of
chlorophyll
molecule.
Are sinks for many nutrients.
Sugar (sucrose) can move up and
down phloem at the same time
Sink:
Fruit& growing points:
Roots:
lG
Are both sinks& sources.
Source:
Water absorbed from soil solution by osmosis.
•
• Sucrose translocated down from leaves to:
1. Be stored as starch.
• Ions are absorbed from soil by active transport.
2. Turn to glucose to be used in respiration to supply • In Spring/winter, stored starch is broken into sucrose to be
energy for growth and active uptake of ions from
translocated up through phloem to leaves and other parts of
soil.
plant when they are not capable of making photosynthesis
Growing Leaves:
Sink
• Use sugar in respiration to
release energy for growth.
• This will continue until leaves
are above ground and
photosynthesising.
Dr. Nihal Gabr
Sucrose move up phloem from root(source)
through stem to leaves(sink)
Dr
Root:
Source:
There is fewer leaves.
So less photosynthesis.
So light is a limiting factor.
And starch is broken into sucrose.
To be translocated through phloem.
To different parts of plant that need
energy for growth for forming new
shoot & leaves.
063
_
62
In summer/
early autumn.
Sucrose move up&down through phloem from leaves
(source) through stem to root(sink)/flower.
.N
In autumn/
spring
iha
Sink:
Leaves:
Source:
There is plenty of sunlight which they
trap.
To carry photosynthesis.
And make glucose.
Which is condensed to sucrose .
To be translocated through phloem.
To :
Flower/fruit:
Roots:
Sink
Sink
To make nectar.
Stored
as starch.
•
Part turned to glucose •
Turned to
to be used in respiration
glucose to be
to release energy for
used in
growth& cell division.
respiration....etc
Part needed to be stored
.
in fleshy part of fruit.
Sixth: plant adaptation
If the plant has short supply of water
The plant starts to reduce water loss by:
2.Leaf fall:
In sever conditions as in winter, so plants
allow leaf to fall
So no water loss can occur.
But there will be no photosynthesis at the
same time, but the plant can remove
chlorophyll from leaves for storage before
allowing leaves to fall.
1.Wilting:
Where leaves collapse and
stomata close to reduce heat
absorption and evaporation
of water.
1.Aquatic pond plants( hydrophytes)
iha
lG
ab
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1. Large air spaces
For buoyancy and floating of plant and to allow gas diffusion.
2. Thin cuticle:
As no need to reduce water loss.
3. Little thin lignin in xylem , since the leaf is supported by water.
4. Leaves are floating on water surface :
For efficient absorption of light.
5. Stomata found on upper surface of leaf:
To allow diffusion of gases from air and prevent entry of water., as CO2 diffuse faster through air than in water.
6. Roots do not attach to the bed of river or pond
So as not to cut be water current.
Dr
.N
2.plants living in
deserts( Xerophytes)
Waxy
cuticle
Dr. Nihal Gabr
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63
Rolled leaf
Leaf hairs
ab
r
2. Continue with
plants living in
deserts( Xerophytes)
Dr
.N
iha
lG
Explain how each of the following are
adapted to live in deserts.
Epidermis
Stomata
Thick waxy
cuticle
Vascular
bundle
Dr. Nihal Gabr
Hairs
065
*
64
Use the diagram to suggest
three ways in which the
structure of the marram
grass leaf help to reduce
water lose.
Topic
8
Animal Transport
First: Human circulatory system components:
1-Heart.
2- Blood vessels.
3- Blood
1-Heart
4 Chambers
ab
r
1
Is a muscular pump made of cardiac muscles which is a strong type of
muscle thats helps keep the heart contracting without stopping to
keep blood flowing in vessels through out a whole life.
Why are the walls of left
ventricle thicker than that
of right ventricle?
Dr
.N
iha
As left ventricle has stronger walls
to contract with greater pressure to
pump blood to the whole
body,while right ventricle pumps
blood only to lungs.
lG
2 Upper thin walled
chambers( Atria)
2 lowered thick walled
Chambers ( ventricles),
R.v
2
L.v
4 Valves
1-Atrioventricular valves: found
between atria& ventricles
a)-tricuspid valve between right
atrium& right ventricle.
b)- bicuspid valve between left
atrium& left ventricle.
2-Semilunar valves: found at the base
of aorta & pulmonary artery( i.e:
between ventricle & artery.
a)-Pulmonary valve between right
ventricle& pulmonary artery.
b)- Aortic valve between left
ventricle& aorta.
What is the
function of valves?
And how do
valves work?
They prevent the back flow of blood allowing blood to
flow in one direction.
Adaptation:
Where the valve flaps are attached to the inner heart
walls by tendons, which allow the valve to close& hold
the valve flap in place, thus preventing the valve from
flipping up( i.e opening in opposite direction).
Closed
valve
Open
valve
Contraction
Contraction
Dr. Nihal Gabr
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65
3
Septum
Separates the oxygenated blood in
the left heart side from
deoxygenated blood in the right
heart side.
Atrial septum
4
Ventricular
septum
Coronary
arteries
Pulmonary valve
Coronary
artery
ab
r
These are blood vessels which supply blood to heart
muscle, as they need a constant supply of nutrients& O2 ,
used in respiration to release energy needed for
contraction& relaxation.
lG
Why does the heart need this blood supply
though its filled with blood?
iha
Because heart muscles are so thick so that nutrients&
oxygen in blood inside heart wouldn't be able to diffuse to
all the muscles quickly enough.
Dr
.N
Whats coronary heart disease?CHD
Narrowing or Blockage of coronary arteries leading to heart
attack, myocardial infarction, Angina& cardiac arrest.
Whats are the factors that lead to CHD?
1- Smoking( nicotine) which increases blood pressure.
2- diet high in salt, saturated fats or cholesterol leading to
increase in blood pressure.
3- Obesity due to lack of exercising & high fat intake
4- Stress over long period of time.
5- genes so try to having healthy life style.
How coronary arteries become diseased?/
how heart attack can happen?
1-Normal
1-Fatty deposit in artery walls( forming plaque)
section in
2-Thus hardening of artery walls( atheroscelorosis).
3-leading to narrowing of lumen of artery.which might Lead to artery
blockage of artery& formation of blood clot( thrombosis)
4- thus increasing blood pressure& restricting blood flow to heart
muscle.
Heart muscle unable to respire normally, so can't obtain energy
needed to contract.
So heart stops beating( heart attack /cardiac arrest)
Dr. Nihal Gabr
067
f66
2-Fatty
material
Deposits
on artery
wall
3Narrowed
artery
becomes
blocked by
a blood
clot
We will stop at this point to explain circulation& the
practical part then get back to the Rest of human
circulatory system components( blood& blood vessels)
Circulation:
Pulmonary
circulation: it starts
from right ventricle
pumping
deoxygenated blood
out of heart to lungs
and returning into
left atrium as
oxygenated blood.
lG
Dr
.N
=
iha
Humans also have
Systemic circulation:
it starts from Left
ventricle pumping
oxygenated blood
out of heart to body
and returning into
right atrium as
deoxygenated blood.
ab
r
+
Why do
mammals,birds&rept
iles have double
circulation?*
1-because when the
blood enters the lung , it
loses some pressure
given to the blood by
pumping heart, so it
enters the heart again to
raise its pressure before
being delivered into the
body.
2-if the blood is pumped
at high pressure to lungs,
it might result in damage
in lungs.
3- Prevent mixing of
oxygenated&
deoxygenated blood.
This is called double
circulation
Why is it called
double circulation?
Because the blood
passes in heart two
times during one
circulation of body:
1- heart to
body( systemic
circulation)
2- heart to
lungs( pulmonary
circulation)
In which the blood flows through
the heart once for each complete
circuit of the body.
Gills
Ventricle
Atrium
Disadvantages
Rapid fall in velocity and
pressure as blood leaves the gills.
.So slower delivery of oxygen for
respiration in tissues
.pressure of blood too low for
efficient kidney function in
mammals.
Dr. Nihal Gabr
Fish having single
circulation
069
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67
Rest
of body
What is the function of
heart?
Is to bump blood all around the body to:
1- Supply different cells with the needed nutrients( minerals, vitamins & other organic compounds
as glucose) and oxygen.
2- And to remove carbon dioxide and other waste products from cells to be excreted out of body.
How does the heart carry
its function?
Phase
Diastole:
Relaxation of the heart muscle
Filling of heart.
Diastole
Systole:
Contraction of the heart
muscle.
Atrial systole
Ventricle Systole
Relax
Contracts to push blood down
into ventricle
Relax
Ventricle
Relax where blood flows
from the veins through the
atria and some of the blood
trickles downward into the
ventricles through
atrioventricular valves.
Relaxes to receive blood from
atrium
Contract to push blood up
through pulmonary artery/
Aorta out of heart.
Cuspid
valve(atrio
Open
lG
Dr
.N
Semilunar
valves
Open as the pressure in atrium
is greater than that in ventricle,
so it opens preventing the back
flow of blood.
iha
ventricular
valve)
ab
r
Atrium
Close
close
Then the
atria contracts
to push the
blood forcefully
down to the
ventricle.
( atrial
systole)
Dr. Nihal Gabr
070
68
Borg
Close, by pressurised blood in
the ventricle, so that blood is
forced into arteries up to body /
lungs without flowing back.
When
pressure is
greater
behind the
valve, it
opens.
When
pressure is
greater in
front of the
valve, it
Closes.
Open
Then the
ventricle
contracts inwards
on the blood,
increasing its
pressure and
pushing it out of
the heart.
( ventricular
systole)
Explain how blood is pumped
by heart at different pressures?
1-Heart is formed of cardiac muscle which has a pacemaker( in the right atrium), which send
electrical signals through walls of the heart at regular intervals to make the heart muscle contract.
2-Heart has septum separating it into 2 parts( left& right).
3-Ventricles contract increasing pressure on blood to be pumped out of heart where :
a)-Right ventricle: has thinner walls, so lower pressure to pump blood only to lungs.
b)-Left ventricle has thicker walls, so higher pressure to pump blood to hole whole body.
Describe the pressure of blood
in heart's blood vessels?
Blood pressure in Aorta is higher than in pulmonary artery as blood goes longer distance ( to whole
body) , so pumped by more muscular ventricle(L.V) & vice versa.
The muscular walls of the heart differ from other muscles
in that they never become tired or fatigued. Because each
contraction of the heart is immediately followed by
relaxation.
lG
Left atrium
ab
r
Blood pressure in vena cava & pulmonary vein is under low pressure because blood is coming from
capillaries moving under low pressure, then enter veins which have wider lumen than arteries.
Right atrium
SAN
( pacemaker)
Dr
.N
iha
The pattern of contraction and relaxation is kept going by
electrical signals sent from a region of the heart called the
pacemaker.
Explain how the rate of heart
beating is controlled?
The rate at which the heart beats is controlled by the pacemaker, which sends electrical signals
through the walls of the heart at regular intervals, which ensures:
1. That the atria contract just before the ventricle, so blood flows from atria to ventricles.
2. The heart beat is fast enough to meet the demands of the body tissues for oxygen and nutrients ,
and for the removal of wastes as in case of exercising.
What stimulates the increase in
heart rate during exercising?
Linked to respiration
Exercising causes an increase in production of carbon dioxide ( weak acid) from high rate of respiration,
which will lower the pH of blood.
The brain detects this change in pH, sending more frequent impulses to pacemaker, increasing heart rate.
What if the pacemaker stops
working properly?
An artificial pacemaker can be replaced in the person's heart, which produces an electrical impulse at
a regular rate about one impulse per second.
The latest pacemaker can sense changes in breathing , movement, and body temperature, and make
exactly the right adjustments to heart rate.
The battery in pacemaker is usually replaced every year.
Dr. Nihal Gabr
of
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69
Heart beats&Practical part:
Heart rate is the number of heart beats in a minute,
Heart beat: is the flow of blood into heart through veins into atria to ventricles to be pumped
out of heart again through arteries.
which is equal to pulse rate Because,
Pulse rate is caused by the expansion and relaxation of an artery, Caused by heart pushing
blood it
How can you hear your
heart beats?
lG
ab
r
How can you measure
You can measure
You can use a stethoscope where
your heart beats by
your pulse rate?
you will hear a lub- dub sound.
measuring pulse rate
As the sound of the heart beat is the sound of
heart valves. Each complete lub- dub represents
A-You can find a pulse where ever there
one heart beat.
is an artery fairly near the surface of the
skin.
1- inside your wrist
2- just to the side of the big tendons in
neck.
B- stress your fingers over an artery
over a bone( near the skin surface) and
count number of pulses per minute.
iha
He dub is caused by
the closing of the
semilunar
valves( valves leading
out of the heart)
Dr
.N
He Lub is caused by
the closing of the
atrioventricular
valves( valves leading
to the ventricles)
Part of ECG, the
points labelled
P,Q,R,S,T represent
different stages oh
heart beat.
Dr. Nihal Gabr
Dr. Nihal Gabr
072
70
-8
How can the activity of your
heart be monitored in hospitals?
It can be recorded using
electrocardiograph( ECG).
At which little electrodes are stuck onto
the persons body , and the electrical
activity in the heart is recorded as a
mind of graph.
How to calculate heart beat
from an ECG graph?
To measure the heart rate,
measure the time between 2 QRS
complexes, at which:
.1 large square= 5mm= 0.2 sec.
.1line( 1small box)= 1mm= 0.04sec.
1mm=
0,04sec.
Notice that a normal heart rate
ranges from 60 to 75 beats/ min..
Start here.
R
5mm=
0,2sec.
S
ab
r
Q
iha
Effect of the physical activity on
heart rate:
lG
Count the small ( 1mm) squares between two QRS complexes. The ECG paper runs at 25 mm/
sec through the ECG printer,therefore:
Linked to respiration&
hormones
Dr
.N
Increase in exercising ,increases the heart rate in order to:
1- supply active muscles with oxygen and glucose to respire at a higher rate and produce more
energy needed for muscle contraction.
2 rapid removal of carbon dioxide and lactic acid from muscles.
To meet this demand, the heart:
contracts more often – the heart rate increases
contracts more powerfully – the stroke volume increases, pumping a greater volume of blood
with each beat
The changes in heart rate are easily observed by measuring the pulse rate (for example, at the
wrist or side of the neck).
The hormone adrenaline is secreted when we are afraid, stressed or angry. It
also causes the heart rate and stroke volume to increase, preparing us for ‘fight
or flight’.
How To carry an investigation to detect
effect of exercising on heart rate: :
It will be covered in topic respiration
Dr. Nihal Gabr
Dr. Nihal Gabr
073
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71
2-Blood vessels
Arteries
Functi
on
Capillaries
1-Carry blood away from
heart to the tissues.
2-Carry oxygenated blood
except for the pulmonary
artery, under high
pressure.
1- Exchange of substances between
blood& cells:
a)- diffusion of gases (CO2& O2)
b)- allows reabsorption of useful
substances back to blood.
c)- heat exchange( lost/ gained).
d)-Allow passage of WBCs to tissue
fluid
Veins
1-Return blood from
tissues to heart.
Transport
deoxygenated blood
except pulmonary vein
under low pressure
Supply all cells with their
requirements & take away waste
products.
Adapta 1-Thick walls:
tion
To withstand high pressure of
lG
allow RBC to pass).
So blood can move slowly for
exchange of materials.
Narrow lumen with thin walls
together bring blood into close
contact with body cells.
Dr
.N
No valves
2- Narrow lumen:(wide enough to
iha
2-Narrow lumen :
So blood can flow under high
pressure.
3-Thick& strong muscles&
elastic fibers:
Elastic to stress& recoil for
keeping blood moving under high
pressure,
Strong: to with stand the
pulsing of the blood.
Muscular tissue: to have the
ability to
contract(vasoconstriction).
Fibrous: prevents bursting.
1-quite thin walls: as
ab
r
1- Very thin walls, only one cell
thick:
blood as it is pumped by heart. For short distance of diffusion to be in
close contact with body cells., besides
blood passing through it has lost most of
its pressure
No valves
1- *Have pores in their walls which
allow filtration of small Molecules.
2- * large number of branching
capillaries providing large surface
area giving more space for diffusion.
No thick muscles& elastic
fibers
blood is flowing under
low pressure.
2- Wide lumen with
valves:
Wide lumen offers no
resistance to blood flow
under low pressure.
Valves to prevent back
flow of blood with help
of squeezing of nearby
muscles which help
push blood up along
veins.
3- Thin layer of
muscles& elastic
fibers
Have Collagen in
walls to prevent
them from bursting.
1- thin
outer wall
1- Thick
outer wall
3- thick layer
of muscles&
elastic fibers
2-narrow
lumen
1-wall made of
single layer of
cells
2-narrow
lumen
074
72
If
3- thin layer
of muscles&
elastic fibers
2-wide
lumen
Naming blood vessels
Lungs
Pulmonary
artery
Pulmonary vein
Vena cava
Hepatic portal
vein
lG
Gut( S.I)
Kidneys
Renal artery
Dr
.N
iha
Renal vein
Hepatic
artery
Liver
ab
r
Hepatic vein
Aorta
Plasma
3-Blood
2
1
C
A
Dr. Nihal Gabr
Dr. Nihal Gabr
B
075
73
☆
1
Plasma
Forms 55% of blood, yellowish fluid formed of:
Linked to nutrition
A- 90% water
(importance of water)
Which is an important solvent at which all substances are dissolved to be transported to
different parts of body.
B- 10% dissolved
substances.
As Glucose, amino acids, minerals, hormones, CO2, urea.
Over all function
ab
r
Transport of blood cells, plasma proteins( hormones, fibrinogen, hemoglobin, enzymes,
antibodies), soluble nutrients( glucose, amino acids, minerals) , waste products( urea, CO2)
Blood cells
iha
A- white blood cells
lG
2
Dr
.N
1. They have nucleus, can squeeze out of blood through walls of blood capillaries into all parts
of body.
2. They fight pathogens( disease causing bacteria& viruses)
Lymphocytes
( have large nucleus)
Release antibodies in response to specific
antigen; these antibodies have the
following functions:
1- Making agglutination= aggregation of
pathogens together so they can be ingested
by phagocytes.
OR
2-Causing bacteria to lysin( burst of
pathogen's cell wall or membrane)
OR
3- Neutralising of pathogen's toxins.
OR
4- Stop bacteria from
moving( immobilisation)
Dr. Nihal Gabr
Dr. Nihal Gabr
076
74
If
Phagocytes
( long lobed nucleus)
Ingest/ Engulf/ Surround the bacteria
( pathogen) and secrete digestive
enzymes that digest them.
They are attracted & collected at wounds
or sites of infection , to engulf and digest
any micro organism which might get in.
B-Red blood cells
1-Contain
haemoglobin ( iron
containing pigment)
2Biconcave
disc shaped
3-No
nucleus
Increases surface
area to speed up
rate of diffusion of
oxygen in & out of
RBCs
Giving more
space for
haemoglobin.
4- flexible, small in
size( almost equal or slightly
larger than central lumen of
capillaries.
To be squeezed through
even the narrowest
capillaries, and be
closer to surface of
capillary wall to unload
their oxygen& to move
slowly.
C-Platelets:
lG
ab
r
Which picks up
oxygen at
Lungs and let go
of it at all body
tissues.
Linked to
specialised cells.
Dr
.N
iha
Small fragments of cells with no nucleus, that help in blood clotting, reducing loss of blood& entry
of pathogens through cut:
• Upon a cut /wound :
1. Blood vessels are damaged and blood is exposed to air.
2. Platelets stimulates clotting where;
- An enzyme ( thrombin) is released.
- Calcium ions , vitamin K and others blood clotting factors must be present.
3. Soluble fibrinogen ( plasma protein) turned by thrombin enzyme into insoluble fibrin.
4. Fibrin forms a web of fibers to trap blood cells, and platelets stick together and to the surface.
5. Then they dry out forming a scab preventing blood loss and entry of pathogens..
Skin epidermis
RBCs & platelets trapped in a
mesh of fibrin fibres.
Remember that
phagocytes are
attracted and
collected at wounds
or sites of infection,
to engulf and digest
any micro organism
which might get in.
Platelets
Dr. Nihal Gabr
End of capillary constricts to
slow down blood loss.
077
75
-6
Skin dermis
Topic 9
Immunity&disease
A.pathogens
Are microorganisms that live on body of a host and causes disease.
Pathogens cause disease by one of the following mechanisms:
1-Some produce harmful
substances called toxins( waste
products) that spread around
the body and can damage
tissues and organs, they cause
symptoms as fever, rash and
make you feel ill.
3- as a result of the
immune response where
when the host detects
pathogen ,it directs more
blood to sit of infection
which can cause swelling
and fever.
ab
r
2- Other pathogens may
damage our cells by living
in them & using up their
resources, as they start
reproduction forming large
colonies.
As in case
of some viruses
Linked to classification
lG
As in case
of bacteria
Types of micro organisms that can act as pathogens
3.Virus
Influenza, polio, AIDS
iha
1.Fungi
Athlete's foot , ring
worm
4. Protoctist
Malaria, dysentery
.N
2.Bacterium( prokar
yotes)
Tuberculosis, cholera,
syphilis, tetanus
Dr
Notice that TB is now the infectious disease that
causes most death worldwide, due to:
1. Poor disease control program.
2. Resistance to antibiotics.
3. Rapid increase in the population of young adults,
which is the age group most at risk from TB.
Doc
tor
lette 's
r
B.Disease:
There are two types of disease:
2. Infectious diseases
1.Non infectious disease
Dr. Nihal Gabr
080
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76
Are diseases caused by pathogens and are
transmissible diseases that can be transferred
from one organism to another.
Next
page
Disease not transmitted from another individual &
they may have a number of causes:
Deficiency disease like scurvy or rickets.
1.
2. Inherited disease like sickle cell anemia, diabetes.
Degenerative disease like bronchitis, COPD.
3.
Cancer resulting from exposure to U.V rays.
4.
Continue with
2. Infectious disease
A- methods of spread of disease:
2. Indirect contact
1. Direct contact
1.in droplets in air, as when people sneeze or
cough.
Ex: influenza, TB bacteria.
1.Where pathogens can be transmitted by touch.
Ex: athletes' foot.
2.in contaminated food.
Ex: salmonella bacteria that cause food
poisoning.
ab
r
2.Where pathogens can pass from a pregnant
woman to her unborn baby through placenta, or
through breast feeding.
Ex: HIV
lG
3. by vector
Ex: malaria caused by protoctist ( plasmodium)
carried in the saliva of anopheles
mosquito( vector of malaria)
3.Where pathogens can pass through body fluid
contact as in case of sexual intercourse.
Ex: HIV, Gonorrhoea, Syphilis, hepatitis B.
Salmonella bacteria
.N
iha
4.in contaminated water.
Ex: virus causing polio, and bacteria causing
cholera.
Notice that cholera is transmitted through faecal
oral route,i.e using/ drinking water that is
contaminated with faeces of an infected person.
Dr
B- Ways to stop spread of disease.
1.Washing food with clean
water before eating.
2.Eat recently cooked food
as cooking usually
destroys bacteria.
3.Keep food covered away
from animals like house
flies.
4.Keep raw meat ( which
is full of bacteria) away
from fruits& vegetables.
5.Don't keep food at warm
temperature for long
periods.
6. Washing your hands
with antiseptics before
touching food.
Dr. Nihal Gabr
Malaria
Cholera
1.
2.
Sewage treatment .
Avoid usage of
contaminated human
faeces as fertilisers.
3.
Use boiled or
chlorinated water.
4.
Reduce the pool of
infected people using
effective antibiotics,&
oral rehydration
therapy.
081
77
If
1.
Reduce number
of mosquitos by
killing them.
2.
Avoid being
bitten by
mosquito using
insect repellent
& mosquito nets.
TB
1.
2.
Vaccination.
Drink
pasteurised
milk.
3.
Less
overcrowding &
well ventilating
houses.
4.
Balanced&
better diet to
improve
immunity.
Summary
Pathogen
Method of transmission
that causes it
Method to stop its
spread
Food
poisoning
Bacteria
In contaminated food
Personal & food hygiene.......
Cholera
Bacteria
Fecal oral route( contaminated water)
Sewage treatment, using
boiled or chlorinated water.
Malaria
Protoctist
Vector( anopheles mosquito)
Killing mosquito, avoid
being bitten using insect
repellents.
TB
Bacteria
In droplets when people sneeze or cough.
Less overcrowding, well
ventilating houses, balanced
diet to improve immunity,
vaccination, drinking
pasteurised milk.
ab
r
Disease
Direct contact : By touch.
HIV
Direct contact:
Mixing of Body fluids as in sexual
intercourse or from mother to her baby
through placenta or breast feeding.
Blood transfusion of contaminated blood.
Using contaminated syringe or razor
lG
Athletes' foot Fungi
.N
iha
Virus
Avoid breast feeding of
babies of infected mother.
Using condoms, or
femidoms during sexual
intercourse with infected
person.
Using disposable syringe.
C- General ways to stop spread of disease.
Dr
1- Food hygiene.
3- waste disposal.
2- Personal hygiene.
4- Sewage treatment.
1-Food Hygiene
1- Always wash your hands before touching.
Keep you hair out of food (people working in food
serves field usually wear uniforms covering their clothes&
hair)
Never cough or sneeze over food.
Next
page
Dr. Nihal Gabr
using disinfectants ,antiseptics and soap to
keep your hands clean.
082
78
Is
2- Don't allow contact between animals& food as animals
are more likely to have harmful bacteria on them than us.
House flies usually have harmful bacteria on their feet as the
stand on rubbish& faeces, besides when they feed they split
saliva onto food.
So always cover food to keep flies& other animals away.
3- keep raw meat away from other food.
4- Don't keep food at room
Bacterial spores are killed
within 15 mins at 120 C
Pressure
cooker 120C
Boiling
water100 C
lG
temperature or long periods, as bacterial
growth & reproduction is affected
greatly by temperature.
Conditions needed for growth of
bacteria( microbes):
1- warm( usually 37 C)
2- Moist.
3- nutrient rich media.
Fridge : will slow down bacterial growth
Cooking at high temperature: will kill most
bacteria
If cooked food is reheated , it should be
made really hot not just warm.
ab
r
As raw meat always contains bacteria , that is killed once the
meat is cooked, but if bacteria get on other food thats eaten
raw( as fruits& vegetables) they might breed .
So any food that would be eaten raw should be washed with
clean water before eating.
iha
Most growing bacteria are
killed if exposed to temp.
Above 65 C
.N
Dr
5-pasteurizing milk,
Most growing bacteria
grow well between 10C &
48 C
Most growing bacteria do
not reproduce below1 C
Body temp.
37C
Room temp.
20C
Fridge:4C
Freezer:-12C
2-Personal Hygiene
1-If Oil (produced by skin to help keep skin
supple& waterproof), dirt & sweat are left
on skin for long,
They provide breeding grounds for bacteria
These can produce substances that smell
unpleasant
So wash regularly with soap & shampoo to
help remove oil.
Dr. Nihal Gabr
083
79
f-
2- Millions of bacteria in
mouth ( most are
harmless, but some can
cause bad breath& tooth
decay.
Brushing & using mouth
wash can keep harmful
bacteria under control.
3-waste disposal
1-waste food, cardboard, paper packaging, bottles, canes, news paper , magazines,
plastic bags, old tyres are all thrown away
2- collected up at landfill sites
Unsafe landfill
Safe landfill
1-Licensed operators are allowed to add
material to landfill site.
2- Rubbish is checked to make sure its free
from any dangerous material.
3-Rubbish added in even layers, &
compressed to reduce the space it takes.
4- place pipes in rubbish to allow
methane to escape harmlessly into air, or
it can be collected and used as a fuel.
5- when landfill is full, it can be covered
over with soil and grass and trees
allowed to grow.
ab
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1-All kind of rubbish are piled up.
2-Bacteria breed in the waste food,
3-Houseflies, rats& stray dogs search
for food in rubbish.
4-landfill site can become rotted by
decomposers( bacteria), producing
methane gas( which is flammable&
could cause explosion if allowed to
build up)
.N
Pipes that allow gases such
as methane to escape
Dr
Water is pumped
out and treated.
Covering of grass
Well
constructed
landfill
iha
lG
Solution
The liner is waterproof & prevent
pollutants getting into the ground
water
Compact waste
Dr. Nihal Gabr
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4-sewage disposal
Sewage: waste liquid from toilets, bathrooms and kitchens.( its
mainly water containing faeces, urine, toilet papers,
detergents, oil,and many other chemicals)
Raw sewage( untreated sewage) contains many bacteria some are
pathogens.
Poliomyelitis& cholera are two serious diseases that can be
transmitted through water polluted with raw sewage.
So why we need to treat sewage?
Prevent spread of pathogens causing disease like cholera,
typhoid, and poliomyelitis.
To recycle water.
Avoid bad smell and avoid pollution.
1.
Sewage
treatment
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2.
3.
Will be discussed in topic conservation
of resources in ecology.
First line of
defense
lG
Body defenses
A-Natural barriers
Dr
.N
1-Skin has thick outer layer
of dead cells,containing
keratin protein, that stops
pathogens from getting into
the body
iha
Mechanical
barriers
2-Hairs in your nostril
traps dust carrying
pathogens
Chemical
barriers
1-ears has bactericidal
( bacteria killing) wax
2-Tears contain lysozyme
enzyme that destroys
bacterial cell wall.
3-Saliva contain enzymes
that can kill bacteria
4-Acid in the stomach
kills most bacteria
swallowed with food and
drinks
3-Scabs form on the skin if
you get a cut,stopping
pathogens from getting into
your body
5-Sticky mucus in the nose and
lungs traps microbes,and then
cilia sweep it out of the lungs
Also this mucus contains
enzymes that can kill bacteria
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If
B-The immune system
If the pathogen penetrate the first line of defense ,they might reproduce
quickly in the warm,nutrient- filled tissue.....further defense starts to work
depending on blood
Blood contain white blood cells(WBCs) which attack the
invading organism
Antigen
Second line
of defense
Antibody
Pathogen
Pathogens
have chemicals called
antigens(foreign particles),
Antibody
3.Antibody: is a glycoprotein with a particular
shape , made by lymphocytes, secreted in
response to an antigen.
Binds to it and destroys the pathogen.
Different pathogens have different
antigens.
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1.Antigen: is a substance ( surface protein) that
is foreign to the body and stimulates an immune
response .
lG
2.Immune response; the way lymphocyte respond
to pathogen as well as the activity of phagocyte.
iha
Steps of
immune
response
.N
Lymphocytes are white blood cells that ate found in the blood and in lymph nodes( swellings in lymphatic
system).
They ate stimulated by the presence of pathogens to manufacture and release special proteins called antibodies.
2- lymphocytes divide
by mitosis forming
identical cells.
Making clone of
lymphocytes.
Dr
1-Lymphocyte comes in contact
with antigens that fit with the
ABs it can make
3- Lymphocytes
secretes antibodies
4- The antibody binds
to antigen and
destroys them.
Y Y
Y Y.
Antigen
Pathogen
Antibodies work by one of the following mechanisms
1-Causing bacteria to lysin( burst of pathogen's cell wall or membrane)
OR
2- Neutralising of pathogen's toxins.
OR
3- Stop bacteria from moving( immobilisation)
OR
4- Making sticking= aggregation of pathogens together so they can be ingested by
phagocytes which then digest them by enzymes. Continue with
phagocytes
Dr. Nihal Gabr
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E-
Phagocytes are large white blood cells . They ate attracted to wounds or sites of infection by chemical
messages. They leave the blood vessels. and destroy any pathogen they recognise.
2-phagocyte engulf/
ingest the pathogen
3. Pathogens are destroyed by
digestive enzymes secreted into food
sac( vacuole)
Production
of memory
cells
Notice:
Most of the time your lymphocytes
don't produce ABs unless they
recognise pathogen, why?
It would be a waste of material&
energy to do this ( mitosis&
production of ABs)
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1-A pathogen is recognised by
its surface proteins(antigens)
or by antibodies that 'label' it
as dangerous
.N
iha
lG
After the infection ,some lymphocytes are kept as memory cells remaining in blood living for a
very long time,
These are cell that have learnt how to make the antibodies against further attacks by the same
antigens.
They will be able to make the right ones much more quickly in the future.
If a second attack comes by same antigens,your body can destroy the microbes before they have
time to produce a large population and make you ill.
The body is now said to be immune to the disease
You have immunity:
Immunity is the body use of antibodies to combat invasion by pathogens
Second infection with the same type of bacteria.
Amount
Dr
Amount
First infection with a particular type of bacteria.
Days after contaminated food eaten
Days after contaminated food eaten
Primary response
Secondary response
The primary response is slow because at this stage , there
are very few lymphocytes that are specific to the antigen,
where it takes time for lymphocytes to recognise antigen,
and divide by mitosis to form clones snd start producing
antibodies.
The secondary response is faster because now
there are many memory cells, which
quickly divide by mitosis, producing large
clone of lymphocytes, that produces many
more antibodies in secondary response.
Dr. Nihal Gabr
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If
1.Types of immunity
Active immunity
•
Immunity gained when an antigen
enters the body, an immune response
occurs .
and antibodies are produced by body
lymphocytes to defeat against the
Pathogen.
• Immunity gained without an immune
response.
and
antibodies
from another individual
•
are injected or pass from mother to
child across placenta or in breast
feeding.
It is a long term immunity ( life
long)
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It is a short term immunity
• Because there are memory cells which
retain the ability to produce Antibodies.
•
Divided into two types
Because there are no memory cells
produced and antibodies will eventually
break down.
lG
Divided into two types
Artificial active
Pathogens infects
individual
Weakened pathogen
( vaccine)
Natural passive
Injection of
vaccine(weak or dead
form of pathogen)
which doesn't cause
disease but
lymphocytes do
produce antibodies , so
individual now is
immune to this
pathogen.
Dr
Individual contracts
disease but survive,
makes antibodies and
is now immune to
further infection by the
same pathogen.
.N
iha
Natural active
Example immunity to
different strains of the
common cold.
Mother's antibodies
can cross the placenta
and are delivered in
breast milk: where
newborn child will be
temporary immune to
pathogens for which
mother produced
antibodies.
Example vaccination
against rubella
virus( german
measles )in babies.
The best ways to avoid disease
Good balanced diet
Not smoking
Regular exercise
Controlling intake of alcohol& other drugs.
Personal hygiene including sensible sexual behavior
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Artificial passive
Antibodies collected
from blood of
laboratory animal
e.g.horse or rabbit.
Y Y
Y Y.
•
Passive immunity
Adult is now immune
to disease which is:
1. Too fast acting for
own immune
system to deal with
e.g injection of anti
tetanus vaccine
following a deep
dirty cut or wound
2. This offers only a
temporary
immunity, because
memory cells are
not produced.
2.Vaccination
Vaccine: it contains weak or dead pathogen ( virus/ bacteria) .
In response to the vaccine, the lymphocytes in your body produce the correct antibodies to kill
the pathogen and make memory cells, so you become immune with a long term immunity
without falling ill.
The graph shows the level of antibody in the
blood following two injections of vaccine
1.The vaccine is less likely to cause unwanted
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Antibody level in blood
So from the graph what is the advantage to a
person in receiving the vaccine in two doses
rather than a single injection?
( advantages of receiving booster doses)
1.
side effects if given in two smaller doses.
2. (Less effective vaccine need booster
injections) to stimulate secondary response
that give enhanced protection by more
production of memory cells.
lG
2.
Time
Second
vaccination
iha
First
vaccination
.N
It stimulates faster and more
production of antibodies, and its effect
last for longer time.)
3.Auto immune disease
Dr
Disease resulting from malfunction of the immune system , where lymphocytes recognise the
self cells as non self cells( foreign) and produce antibodies against them.
So those having diabetes type 1 , have to
keep receiving regular shots of insulin, as
well as taking care over what they eat, to
keep blood glucose concentration within a
normal level.
Example ;
Diabetes type I in children;
The immune system attacks the
beta cells in the pancreas,
which are responsible for
producing the insulin hormone,
and destroy them.
So insulin is no longer produced
,so blood glucose level is not
controlled
Dr. Nihal Gabr
Insulin can't be taken by mouth, because
its a hormone made from proteins so it
will be digested by stomach enzymes.
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Hypoglycemia
When the blood glucose level goes up and
stays up.
When not eating carbohydrates for a long
time the blood glucose level will drop.
Because no insulin has been secreted, the
liver hasn't built up stores of glycogen thst
can now be broken to down to produce
glucose. So the person has hypoglycemia,
Where cells don't have enough glucose to
respire and release energy.
Symptoms:
Excessive thirst.
Sweet smelling breath.
High(overflow) of glucose in urine.
Blurred vision.
Sometime increase in heart and breathing
rate.
1.
2.
3.
Symptoms:
Very tired
Shows confusion.
Irrational behavior
ab
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1.
2.
3.
4.
5.
Hyperglycemia
.N
iha
Solution
lG
Having a blood glucose level that swings very high and very low can, over long periods of time,
do damage to numerous body organs.
So it is important that a person with type 1 diabetes tries to keep their blood concentration
within reasonably normal limits.
Dr
1. Those having diabetes type 1 , have to keep receiving regular shots of insulin, as
well as taking care over what they eat, to keep blood glucose concentration within a
normal level.
2. Regular checking of blood glucose level using a glucose meter device t home.
3. They can also test their urine for glucose using a simple dipstick, as urine should
contain no glucose, but if the if a person's blood glucose level rises very high then
the kidneys are not able to reabsorb it all from the filtrate in the nephron, and
some remains in the urine that is excreted.
Dr. Nihal Gabr
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