Worksheet No: 1/22-23
Date: _____________
UNIT.1: CHARACTERISTICS AND CLASSIFICATION OF LIVING ORGANISMS
Answer the following.
1.
Table 1.1 shows some features of the five groups of vertebrates.
Complete Table 1.1 to compare the five groups of vertebrates using a tick (✓) to indicate if
the group shows the feature, or a cross (X) if not.
group of
vertebrates
birds
scaly skin
external ear
(pinna)
feathers
✓
x
✓
glands
X
bony fish
amphibians
reptiles
mammals
[4]
2.
The freshwater mussel, Margaritifera margaritifera, is a mollusc which lives in rivers and
streams.
When the mussel reproduces, gametes are released into the water and fertilisation takes
place.
The embryos, in the form of larvae, attach themselves to the gills of fish and develop there
for a few months.
The larvae then release themselves and grow in sand in the river, feeding by filtering food
from the water.
The number of mussels is falling due to human predation and the species is threatened with
extinction.
(a) The mussel belongs to the group known as the molluscs. State two features you would
expect the mussel to have.
1.
2.
[2]
(b) Explain how the species name of the freshwater mussel can be distinguished from its
genus.
[1]
(c) State the type of reproduction shown by the mussel.
Explain your answer.
type of reproduction
explanation
[2]
(d) (i) Fish gills have the same function as lungs. Suggest one advantage to a mussel
larva of attaching itself to fish gills.
[1]
(ii) The mussel develops on the fish gills. Define the term development.
[1]
3.
Crabs are classified, along with prawns, shrimps, and lobsters, as crustaceans. Most crabs
live in the sea, although some live in freshwater and there are a few land-dwelling crabs.
Fig. 1.1 shows the structure of a typical crab.
cheliped / claw
eye
carapace
walking legs
abdomen, often tucked
beneath the rest of the body
Fig. 1.1
a. State the group of animals that includes crustaceans, insects, arachnids and
myriapods.
[1]
Fig. 1.2 shows four different species of crab.
A spiny spider crab
Maia squinado
ii.
West African fiddler crab
Uca tangeri
i.
iii.
Fig. 1.2
hairy hermit crab
Pagurus hirsutiusculus
sand crab
Portunus pelagicus
b. Biologists use dichotomous keys to identify different species.
Use Fig. 1.1 and Fig. 1.2 to state one visible feature of each species of crab A,
B, C
and D, that could be used in a dichotomous key to identify crabs.
A
B
C
D
[4]
2
Fig. 1.1 shows a bacterium, a virus and a fungus.
not to scale
(a) Complete the table to compare the three organisms shown in Fig. 1.1 by using
a tick (✓) to indicate if the organism shows the feature, or a cross ( x) if it does
not. The first row has been completed for you.
Feature
produces
spores
Hyphae
Capsul
e
Nucleus
bacteria
x
virus
fungus
✓
Worksheet No: 2/22-23
Date: _____________
UNIT.2: ORGANISATION AND MAINTENCE OF THE ORGANISM.
Answer the following.
1.
Fig. 5.1 shows a root hair cell.
A
Fig
.
5.1
(a)
Name structures A, B and C.
A
B
C
[3]
(b) Explain two ways in which root hair cells are adapted to carry out their functions.
1.
2.
[4]
3.
Fig. 1.1 shows an animal cell and a plant cell as seen with a light microscope.
animal cell
plant cell
Fig. 1.1
(a)
Table 1.1 shows some structural features of the animal cell and the plant cell in Fig. 1.1.
Complete the table by
•
•
finishing the row for nucleus
adding three structural features, visible in Fig. 1.1, and indicating whether they are
present (✓) or absent (✗) in the animal cell and in the plant cell.
Table 1.1
structural feature
cell wall
animal cell
plant cell
✗
✓
Nucleus
[4]
6
Some cells in shoot tips become leaf cells and others become cells in the
stem or in flowers. Explain why it is important that only some of the genes in
cell A are expressed in these cells.
.....................................................................................................................................
..............
.....................................................................................................................................
..............
.....................................................................................................................................
..............
.....................................................................................................................................
..............
.....................................................................................................................................
..............
.....................................................................................................................................
..............
.....................................................................................................................................
........ [3]
7
8
Worksheet No: 3/22-23
Date: _____________
UNIT.3: MOVEMENT IN AND OUT OF CELLS.
Answer the following.
1.
(a) Explain how water is absorbed by plant roots.
[3]
(b) Young plants were grown in pots of sand for four weeks.
Some plants were watered with distilled water at pH 7.0 (no salts).
Most pots were watered with solutions containing different concentrations of salt(sodium
chloride) at pH 7.0. The plants were kept at 20 oC. The growth of the plants was measured
after four weeks.
The growth of the plants is shown in Fig. 4.1 as percentages of the growth of the plants
watered with distilled water.
100
90
80
70
growth as
percentages
of the growth
of the plants
given distilled
water
60
50
40
30
20
10
0
0
100
200
300
concentration of sodium
chloride / arbitrary units
8
400
500
60
(i) Describe the results shown in Fig. 4.1.
You will gain credit for using the figures in the graph to support your answer.
[3]
(ii) Explain the difference in growth between the plants watered with low
concentrations and those watered with high concentrations of salt solution.[4]
2. Ecologists study plants and animals in their natural environment.
Some ecologists inserted probes into the water-conducting tissue in trees, as shown in Fig. 4.1.
The ecologists measured the time taken for water to move up from probe 1 to probe 2.
tree
probe 2
probe 1
data logger
9
(i)
Name the water-conducting tissue into which the two probes were inserted.
..................................................................................................................................... [1]
(ii)
Describe how the structure of this water-conducting tissue is adapted to its function.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
(a) Explain the mechanism of water movement from the roots up the tree to the leaves.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [4]
10
(b) Fig. 4.2 shows the rate of water conduction up three different trees in a forest over 24 hours.
2.5
tree A
2.0
1.5
rate of water
conduction
/ dm3 per hour
1.0
tree B
0.5
tree C
0
(i)
4
8
12
16
20
time /
24
Describe the rate of water conduction in tree A, during this 24 hour period.
You will gain credit for using the data in Fig. 4.2 to support your answer.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [3]
(ii)
Suggest how the ecologists used the data in Fig. 4.2 to calculate the total volume of
water used by a tree in 24 hours.
...........................................................................................................................................
..................................................................................................................................... [1]
11
Worksheet No: 4/22-23
Date: _____________
UNIT.4: BIOLOGICAL MOLECULES
Answer the following
1.
12
13
Worksheet No: 5 /22-23
Subject: Biology
Date: _____________
Enzymes
1.
2.
b.
3.
4.
(a) The reactions of chemical digestion are catalysed by enzymes.
Fig. 1.1 shows the stages of an enzyme-catalysed reaction.
enzyme
A
B
C
D
Fig. 1.1
State the names of A to D in Fig. 1.1.
A ...............................................................................................................................................
B ...............................................................................................................................................
C ...............................................................................................................................................
D ...............................................................................................................................................
Worksheet No: 6/22-23
Date: _____________
UNIT.6: PLANT NUTRITION
Answer the following.
1.
A.) Define the term tissue.
-----------------------------------------------------------------------------------------------------------------
b.) Describe their main features and functions.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Worksheet no. 7
Biology
Date:
1
Fig. 6.1 shows the alimentary canals of two mammals, an insect-eating bat, which is a carnivore,
and a rabbit, which is a herbivore.
V
0
10
cm
0
W
2
cm
insect-eating bat
rabbit
Fig. 6.1
(a) Name the organs labelled V and W.
V ........................................................................................................................................
W .......................................................................................................................................
[2]
(b) Explain the role of mechanical digestion.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[3]
2
Fig. 3.1 shows part of the thoracic and abdominal cavities of a human.
thoracic
cavity
G
H
P
O
J
K
abdominal
cavity
N
M
L
Fig. 3.1
(a) (i)
Name the structures labelled G, H and M.
G .......................................................................................................................................
H ........................................................................................................................................
M .......................................................................................................................................
[3]
(ii)
Table 3.1 shows five functions of organs in the abdominal cavity.
Complete the table by:
•
•
naming the organ that carries out each function
using the letters from Fig. 3.1 to identify the organ named.
One row has been completed for you.
Table 3.1
function
name
letter from Fig. 3.1
pancreas
K
conversion of glucose to glycogen
secretion of insulin and glucagon
absorption of products of digestion
storage of bile
chemical digestion of protein in an
acidic pH
[4]
(b) Fat is particularly difficult to digest as it is not water soluble and forms spherical globules in
the alimentary canal.
Fig. 3.2 is a diagram showing what happens to fat globules when mixed with bile.
fat globules
Fig. 3.2
(i)
Name the process shown in Fig. 3.2.
.......................................................................................................................................[1]
(ii)
Explain the advantage of the process shown in Fig. 3.2.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(c) Insulin and glucagon are hormones secreted by the pancreas to control the concentration of
glucose in the blood.
(i)
Complete Table 3.2 to show how the uptake of glucose by cells and the concentration of
glucose in the blood respond when the two hormones are secreted.
Use the words increases, decreases and stays the same to complete the table.
Table 3.2
hormone
uptake of glucose by cells
concentration of glucose in
the blood
insulin
glucagon
[2]
(ii)
State another hormone that influences the concentration of glucose in the blood.
.......................................................................................................................................[1]
(d) Explain why the control of the concentration of glucose in the blood is an example of negative
feedback.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
[Total: 16]
3
(a) Describe how food is moved along the small intestine.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [2]
(b) The small intestine is lined by many villi.
Fig. 5.1 shows a longitudinal section of a villus.
Fig. 5.2 shows a cross-section of the same villus at V – W.
The diagrams are not drawn to the same scale.
P
Q
W
V
R
microvilli
S
Fig. 5.1
cell T
Fig. 5.2
(i)
Name structures P, Q, and R.
P ........................................................................................................................................
Q .......................................................................................................................................
R .................................................................................................................................. [3]
(ii)
The blood that flows from S enters a vein.
Name the vein that transports blood away from the small intestine.
...................................................................................................................................... [1]
(iii)
Cell T is an example of the cells that form the surface of the villi.
Explain why there are many microvilli on cell T.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
(iv)
Some of the cells on the surface of the villi secrete mucus for protection.
Suggest what the villi need to be protected against.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [2]
[Total: 10]
4
The alimentary canal is adapted for chemical and mechanical digestion.
(a) Explain how chemical digestion differs from mechanical digestion.
[3]
Fig. 5.1 is a diagram of the human alimentary canal.
A
B
C
J
D
H
E
G
F
Fig. 5.1
(b) Table 5.1 shows four functions of the alimentary canal.
Complete the table by:
•
naming the part of the system that carries out each of the functions;
•
using the letters from Fig. 5.1 to identify the part of the system named.
One row has been completed for you.
Table 5.1
function
produces bile
name of part
letter from Fig. 5.1
liver
J
most soluble food is absorbed
into the blood
indigestible food is egested
hydrochloric acid is produced
protease, lipase and amylase
are produced
[4]
(c) Some people develop gallstones, made of cholesterol, that accumulate in the gall
bladder and the bile duct. Gallstones block the flow of bile.
Explain how gallstones can affect the digestion of fat.
[3]
Worksheet No: 8/22-23
Date: _____________
UNIT. 8: Transport in Plants
Answer the following.
3
4
5
6
Worksheet No: 9/22-23
Date: _____________
UNIT.9: Transport in Animals
Answer the following.
1. Complete Table 1.1. [6]
Table 1.1
function
letter on
Fig. 1.1
name
A
aorta
structure that separates oxygenated and
deoxygenated blood
structure that prevents backflow of blood
from ventricle to atrium
blood vessel that carries oxygenated blood
blood vessel that carries deoxygenated blood
structure that prevents backflow of blood
from pulmonary artery to right ventricle
chamber of the heart that contains oxygenated blood
chamber of the heart that contains deoxygenated blood
(a)
(i)
Doctors recommend that a healthy diet can reduce the risk of coronary heart disease.
Give one other lifestyle improvement patients can make that can reduce the risk of
coronary heart disease.
................................................................................................................................
................................................................................................................................
(ii) Sometimes surgery is required to treat coronary heart disease.
[1]
Describe one named example of surgery that can treat coronary heart disease.
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
3
[2]
Mammals have a double circulation system.
(a) Explain what is meant by a double circulation system.
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[1]
(b) Table 5.1 shows some of the main organs in a mammal and the vessels that deliver blood and
take it away.
Complete the table. [5]
Table 5.1
organ
blood vessel
delivers blood
heart
lungs
takes blood away
1 .....................................................
1 aorta
2.............................................. vein
2artery
pulmonary artery
........................................................
1 hepatic artery
liver
hepatic vein
2 .....................................................
kidney
............................................. artery
................................................ vein
4
Table 4.1 shows the composition of blood plasma.
component
concentration in the plasma
adrenaline / ng dm–3
10 – 100
fibrinogen / g dm–3
1.7 – 4.0
glucose / mg dm–3
700 – 1000
hydrogencarbonate ions / g dm–3
insulin / g dm–3
1.1 – 1.4
0.33 – 0.40
lactic acid / mg dm–3
50 – 200
sodium ions / g dm–3
3.1 – 3.4
urea / mg dm–3
70 – 200
(a) From Table 4.1, name:
(i)
an excretory product
...................................................................................................................................... [1]
(ii)
a plasma protein.
...................................................................................................................................... [1]
(b) (i)
State what could cause the lactic acid concentration in the blood to increase to
200 mg dm–3.
...................................................................................................................................... [1]
(ii)
State the function of fibrinogen.
...................................................................................................................................... [1]
(iii)
State two effects that a concentration of adrenaline of 100 ng dm–3 might have on the
body.
...........................................................................................................................................
...................................................................................................................................... [2]
(c) Table 4.1 shows that the glucose concentration varies between 700 and 1000 mg dm–3.
Describe the role of the liver in regulating the concentration of glucose in the body.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
.............................................................................................................................................. [3]
(d) Lymphocytes and phagocytes are white blood cells.
A woman had some blood tests taken before and during a bacterial infection.
Table 4.2 shows the number of white blood cells in the two blood samples.
Table 4.2
white blood
cells
(i)
mean number of cells per mm3 of blood
before infection
during infection
lymphocytes
1300
3500
phagocytes
2000
7500
Calculate the percentage increase in lymphocytes that occurred during the bacterial
infection.
Show your working and give your answer to the nearest whole number.
answer .............................................. % [2]
(ii)
Describe the role of phagocytes in defence against disease.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [3]
(iii)
Describe the roles of white blood cells in tissue rejection.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[3]
[Total: 17]
1
Fig. 4.1 is an electron micrograph of some red blood cells and lymphocytes.
Fig. 4.1
(a) Lymphocytes respond to infection by making and releasing special protein molecules
called antibodies.
Describe how antibodies provide protection from diseases caused by viruses and
bacteria.
[3]
Worksheet No: 10/22-23
Date: _____________
UNIT.10: Diseases and Immunity
1. Sub-Saharan Africa has the highest proportion of the population living with HIV in the world. The World
Health Organization estimates both the total number of people who live with HIV and the total number of
people that are newly infected each year.
Fig. 5.2 shows the estimated numbers for sub-Saharan Africa between 1990 and 2010.
Number of people living with HIV, sub-Saharan Africa. 1990–2010
25
20
millions
of people 15
10
5
0
1991 1993 1995 1997 1999 2001
2003 2005 2007 2009
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
year
Number of people newly infected with HIV, sub-Saharan Africa. 1990–2010
3.0
2.5
2.0
millions 1.5
of people
1.0
0.5
0
1991 1993 1995 1997 1999 2001
2003 2005 2007 2009
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010
year
Fig. 5.2
(i)
Summarise the changes between 1990 and 2009 in the number of people living with HIV
and the number of people newly infected with HIV.
number of people living with HIV........................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
number of people newly infected with HIV .........................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[4]
(ii)
Suggest why in 2010 the number of people living with HIV increased but the number of
newly infected people decreased.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(iii)
Describe three ways in which HIV is transmitted from infected to uninfected people.
1 .........................................................................................................................................
...........................................................................................................................................
2 .........................................................................................................................................
...........................................................................................................................................
3 .........................................................................................................................................
.......................................................................................................................................[3]
(iv)
Describe the effects of HIV on the immune system.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[3]
[Total: 17]
3
The human immunodeficiency virus (HIV) infects white blood cells. The virus is reproduced
inside these white blood cells.
(a) Describe what may happen to viruses that leave infected white blood cells.
[2]
(b) Describe the possible long-term effects of HIV on the immune system.
[3]
(c) People with HIV may be treated with a variety of drugs.
(i) Define the term drug.
[1]
(ii) Explain why antibiotics cannot be used to control HIV.
[2]
[Total: 8]
Worksheet No: 11/22-23
Date: _____________
UNIT.11: GAS EXCHANGE SYSTEM IN HUMANS
1
(a) Fig. 1.1 shows the human gas exchange system. The functions of the parts of the gas exchange
system are given in Table 1.1.
A
M
B
K
C
J
D
H
E
G
F
Complete Table 1.1. One row has been done for you.
[6]
Table 1.1
function
structure that makes sounds
bone that provides protection for the lungs
airway that allows passage of air only into
the right lung
airway that allows passage of air into
both lungs
contracts to increase volume of thorax
muscle that contracts to lower the ribcage
site of gas exchange
letter on Fig. 1.1
name
A
larynx
(b) The gas exchange system contains cartilage.
Describe the function of cartilage in the gas exchange system.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[2]
(c) Soon after starting physical activity the concentration of carbon dioxide in the blood increases.
(i)
Name the process inside cells that produces carbon dioxide.
................................................................................................................................
................................................................................................................................
[1]
(ii) State the effect on breathing of an increase in carbon dioxide concentration in the blood.
................................................................................................................................
................................................................................................................................
................................................................................................................................
2
Fig. 4.1 shows part of the human gas exchange system.
K
L
[1]
(a) (i)
Name structure K.
...................................................................................................................................... [1]
(ii)
Ciliated cells and goblet cells line structure L.
Explain the function of these cells in structure L.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [3]
(b) Gas exchange occurs at the alveoli.
(i)
Describe how oxygen molecules move from the alveoli into the blood.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...................................................................................................................................... [3]
(ii)
Name one gas that is found in a higher concentration in expired air than in inspired air.
...................................................................................................................................... [1]
3
The pressure in the lungs of a student before and during the start of a volleyball match was
recorded.
The results are shown in Fig. 2.1.
lung pressure
/ arbitrary units
Fig. 2.1
(a) (i)
Use the results in Fig. 2.1 to calculate the breathing rate before the start of the match.
Express your answer to the nearest whole number.
Show your working.
..................................breaths per minute
[2]
Worksheet No: 12/22-23
Subject: Biology
Date: _____________
Unit: Respiration
1
Researchers designed an investigation to find the effect of increasing levels of exercise on two
groups of people.
The first group of people were trained cyclists and the second group were untrained cyclists.
The researchers asked all the people to cycle at four levels of effort: 30%, 45%, 60% and 75% of
their maximum cycle speed.
They cycled for eight minutes at each level of effort.
(a) The researchers predicted that the pulse rate of all the cyclists would increase during exercise.
Explain this prediction.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
Fig. 3.1 shows the average concentration of lactic acid in the blood of the trained cyclists and
untrained cyclists in the investigation.
level of effort
30%
45%
60%
after
exercise
75%
10
key
untrained cyclists
trained cyclists
8
average 6
lactic acid
concentration 4
/ arbitrary units
2
0
0
8
16
24
time / minutes
Fig. 3.1
32
40
(b) Describe the effect of the increasing levels of effort on the average lactic acid concentration in
the blood of the untrained cyclists.
You should use data from Fig. 3.1 in your answer.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
(c) Lactic acid is produced in the muscles during anaerobic respiration.
(i)
Describe how the lactic acid produced in muscle cells enters the blood.
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[1]
(ii)
Name the component of the blood that transports lactic acid.
.......................................................................................................................................[1]
(d) Explain why the lactic acid concentration in the blood in trained cyclists is different from the
untrained cyclists eight minutes after the exercise.
You should use data from Fig. 3.1 in your answer.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
(b) A rowing machine is a piece of apparatus that is used in many fitness centres.
Fig. 4.1 shows a man training on a rowing machine. The man in the photograph has his arms
extended during the rowing stroke as shown in Fig. 4.2.
Fig. 4.1
Fig. 4.2
Use Fig. 4.2 to describe how the hand is moved closer to the chest during the rowing stroke.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
exercise starts
(i)
exercise ends
Explain why there is a steep increase in the man’s oxygen consumption at the start of the
exercise.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[4]
(ii)
It took 10 minutes after the man had stopped rowing for his oxygen consumption to
decrease to its resting value.
On Fig. 4.3 draw a line between 20 minutes and 35 minutes to show the change in
oxygen consumption after exercise has stopped.
[2]
(iii)
Explain why the man’s oxygen consumption did not return to the resting value
immediately after exercise.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[4]
[Total: 15]
Worksheet No: 13/22-23
Date: _____________
UNIT.13: EXCRETION IN HUMANS
1
The lungs and the kidneys are excretory organs of the human body.
(a) (i)
Define the term excretion.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[3]
(ii)
State an excretory product that is passed out through the lungs.
.......................................................................................................................................[1]
(iii)
Outline the role of the liver in excretion.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[3]
(b) Fig. 4.1 is a vertical section of the kidney.
K
L
P
O
N
M
Fig. 4.1
Table 4.1 shows the functions of parts of the kidney.
Complete the table by:
•
•
naming the part of the kidney that carries out each function
using letters from Fig. 4.1 to identify the part of the kidney named.
One row has been completed for you.
Table 4.1
function
name of part
letter from Fig. 4.1
medulla
L
blood is filtered
concentration of urine is
determined
urine flows to the
bladder
blood is carried into the
kidney
blood flows out of the
kidney
[4]
(c) People with kidney disease are often treated in renal dialysis clinics. Their blood passes
through tubes lined with a special membrane for about three hours.
(i)
State two waste substances that are removed from the blood by dialysis.
1 ........................................................................................................................................
2 ........................................................................................................................................
[2]
(ii)
Kidney patients may be given a kidney transplant. State one advantage and one
disadvantage of kidney transplants compared with dialysis.
advantage ..........................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
disadvantage .....................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
[2]
[Total: 15]
(a) Glucose is reabsorbed, back into the blood, by active transport.
Define active transport.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(b) Give one example, other than glucose, of a substance that is reabsorbed into the blood from
the renal tubule.
...............................................................................................................................................[1]
C.) Dialysis is a treatment for kidney disease.
Fig. 5.2 shows a dialysis machine.
dialysis machine
blood pump
arm
used
ysis dial
fluid
fresh
ysis dial
fluid
Fig. 5.2
(i)
The composition of the dialysis fluid changes as it passes through the dialysis machine.
Complete Table 5.1 using the words ‘low’, ‘high’, ‘same’ or ‘none’ to
show how theconcentration of each substance changes in the dialysis
fluid.
The last one has been done for you.
Table 5.1
concentration of substance in:
substance
blood before
dialysis
glucose
normal
salts
high
urea
high
toxins
high
used dialysis fluid
fresh dialysis fluid
high
low
[3]
Worksheet No: 14-1/22-23
Date: _____________
UNIT.14: Co-ordination and response
Worksheet No: 14/22-23
Date: _____________
UNIT.14: MOVEMENT IN AND OUT OF CELLS.
1.a.) Fig. 2.3 shows three pots of seedlings that have been kept in different conditions.
pot P
pot Q
pot R
Fig. 2.3
(i)
State the conditions in which pots P and Q were kept.
P
.............................................................................................................................
Q.............................................................................................................................
[1]
(ii) State the name of the growth response shown by the seedlings in pot R.
................................................................................................................................
[2]
(iii) Explain the advantage to the seedlings of this growth response.
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
[2]
(iv) Auxins control the growth responses of seedlings.
Explain how auxins control the growth response of the seedlings in pot R.
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
[4]
2
Fig. 3.1 is a diagram of human skin in cold weather.
P Q R
S
T
U
V
Fig. 3.1
(a) Table 3.1 shows the responses of the skin to cold weather.
Complete the table by:
•
•
naming the parts of the skin that respond to cold weather
using the letters (P to V) from Fig. 3.1 to identify these parts of the skin.
Table 3.1
responses of skin to cold weather
name of part
letter from Fig. 3.1
stands upright to trap air
constricts to reduce blood flow to skin
stops producing sweat
[3]
(b) The response of the skin to cold weather is an involuntary action.
Explain how an involuntary action differs from a voluntary action.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
(c) Describe how the nervous system coordinates the response of the skin to cold weather.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[4]
(d) Explain how negative feedback is involved in the control of body temperature.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
[Total: 13]
(e) Blood samples were taken from each of the blood vessels J, K, L and M two hours after a
meal of rice. Table 2.1 shows the concentration of glucose in these blood samples.
Table 2.1
blood vessel
blood glucose concentration
/ mg per 100 cm3
J
135
K
128
L
181
M
133
Calculate the percentage increase in blood glucose concentration between blood vessel J
compared with L. Express your answer to the nearest whole number.
Show your working.
............................................................ %
[2]
(f)
Control of blood glucose by the liver is an example of homeostasis.
(i)
Explain how the liver lowers blood glucose concentration when it is too high.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(ii)
Name one other factor in the human body that is also controlled by homeostasis.
...........................................................................................................................................
.......................................................................................................................................[1]
(iii) State one other function of the liver, besides homeostasis and processing amino acids.
...................................................................................................................................................
...............................................................................................................................................[1]
3
Fig. 3.1 is a diagram that shows the control of blood glucose concentration.
blood glucose concentration
at 90 mg per 100 cm3
increase in glucose
in the blood
decrease in glucose
in the blood
blood glucose concentration
above 90 mg per 100 cm3
storage of glucose
as glycogen
blood glucose concentration
below 90 mg per 100 cm3
blood glucose concentration
at 90 mg per 100 cm3
breakdown of
glycogen to glucose
Fig. 3.1
(a) (i)
State one reason why the concentration of glucose in the blood increases and decreases
...........................................................................................................................................
.......................................................................................................................................[2}
(ii)
Name two places in the body where glycogen is stored.
1 ........................................................................................................................................
2 ........................................................................................................................................
[2]
b.) If the blood glucose concentration is very high there is a decrease in the water
potential of the blood. This may damage the red blood cells.
Explain how a decrease in water potential of the blood may damage red blood cells.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
Worksheet No: 15/22-23
Date: _____________
UNIT.15: Drugs
1
The fungus, Trichophyton violaceum, reproduces asexually by releasing spores.
A single spore was placed in the centre of a Petri dish containing an agar medium with
starch and protein.
Fig. 1.1 shows the fungus that grew from the spore.
Fig. 1.1
(a) State the name given to
(i)
the body of the fungus that grows from a single spore
[1]
(ii)
the thin threads that make up the body of the fungus.
[1]
(b) Describe how a fungus, such as T. violaceum, obtains nutrients from the agar medium.
[4]
Streptomyces, a soil bacterium, is a major source of antibiotics that are produced by
pharmaceutical companies. An antibiotic sensitivity test can be carried out to help doctors
decide which antibiotic should be used to treat a specific disease, such as gonorrhoea.
Gonorrhoea bacteria isolated from a person are grown on an agar medium. A ring with
eight different antibiotics (1 to 8) is placed on the agar medium and left for 24 hours at
35 °C.
Fig. 1.2 shows the growth of bacteria on the agar medium after 24 hours.
1
bacterial
growth
2
8
7
3
6
4
5
Fig. 1.2
(c) (i)
Suggest why there is a clear area around some of the antibiotics.
[2]
(ii)
Explain why antibiotics 1 and 5 would not be chosen to treat the gonorrhoea
infection.
[2]
2
When bacteria are spread onto agar in a Petri dish they form colonies. Each colony forms
from one bacterium. Fig. 4.1 shows an investigation into antibiotic resistance in a species of
bacterium that causes disease.
no antibiotic
added to agar
agar
A
colonies of bacteria
transfer of
bacteria
culture to
dish A
START OF PROCESS
culture of bacteria
in a liquid medium
antibiotic
added
to agar
transfer of
bacteria
culture to
dish B
B
transfer of bacteria
culture from dish B to
liquid medium
bacteria exposed
to X-rays
transfer of bacteria
culture to dish D
transfer of bacteria
culture to dish C
after 24 hours
antibiotic
added
to agar
antibiotic
added
to agar
C
D
Fig. 4.1
(a) Explain what is meant by the term antibiotic.
[2]
(b) Explain why
(i)
only a few bacteria grew in dish B compared with dish A,
[1]
(ii)
more bacteria grew in C than in B.
[1]
(c) Fig. 4.1 shows the effect of an antibiotic on a species of disease-causing bacterium.
Suggest why antibiotics should not be used too often.
[2]
(d) Explain the possible effect of the X-rays on the bacteria.
[3]
(e) State two ways in which the structure of a bacterium differs from the structure of a virus.
1.
2.
(f)
[2]
Human Immunodeficiency Virus (HIV) infects cells of the immune system.
Describe the effects of HIV on the immune system.
[4]
[Total: 15]
(a) Many different antibiotics are used.
Suggest why some antibiotics are used less frequently than others.
[3]
[Total: 6]
Worksheet No: 17/22-23
Date: _____________
UNIT.16: Reproduction
1
The menstrual cycle involves monthly changes in the ovary and the uterus.
(a) Fig. 5.1 shows the sequence of changes within the ovary that occur during the menstrual
cycle.
R
T
S
Fig. 5.1
(i)
Name structures R and S.
R ........................................................................................................................................
S ........................................................................................................................................
[2]
(ii)
State the name of the process that is occurring at T.
.......................................................................................................................................[1]
(b) The ovary secretes hormones that control the growth and maintenance of the lining of the
uterus.
Name the hormone that stimulates:
(i)
the growth of the lining of the uterus during the first half of the menstrual cycle
.......................................................................................................................................[1]
(ii)
the maintenance of the lining of the uterus during the second half of the menstrual cycle.
.......................................................................................................................................[1]
(c) Fig. 5.2 is an electron micrograph showing a sperm cell on the surface of an egg cell.
Fig. 5.2
(i)
State three ways in which a sperm cell differs from an egg cell.
1 ........................................................................................................................................
2 ........................................................................................................................................
3 ....................................................................................................................................[3]
(ii)
Human body cells have 46 chromosomes. Human egg and sperm cells have
23 chromosomes each.
What term is used to describe the number of chromosomes in a gamete, such as an egg
cell or a sperm cell?
.......................................................................................................................................[1]
(iii)
State the organ in which fertilisation occurs in humans.
.......................................................................................................................................[1]
(iv)
Describe what happens between the event shown in Fig. 5.2 and implantation in the
uterus.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[4]
(d) Clomiphene citrate is a fertility drug that has been available for over 50 years. As part of a
fertility treatment clomiphene citrate is taken once a day (daily dose) for about five days.
Researchers investigated the use of the drug in Denmark between 1974 and 1993. The
results of their study are shown in Fig. 5.3.
1800
1600
1400
1200
total number of 1000
daily doses of
clomiphene
800
citrate per year
600
400
200
0
1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994
year
Fig. 5.3
(i)
Describe the change in the use of clomiphene citrate in Denmark between 1974 and
1993. Use data from Fig. 5.3 in your answer.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
2
Fig. 5.1 is a diagram showing the events from pollination to fertilisation in a species of flowering
plant.
A
stigma
pollen grain
style
ovary
B
C
Fig. 5.1
(a) Name the likely method of pollination for the flowers shown at A in Fig. 5.1. Give an explanation
for your choice.
method of pollination .................................................................................................................
explanation ...............................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
[3]
(b) In Fig. 5.1 pollen is transferred from one plant to another.
State the name for this type of pollination.
...............................................................................................................................................[1]
(c) Name structure B shown in Fig. 5.1 and state its function.
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(d) Fertilisation occurs at C as shown in Fig. 5.1.
Describe what happens at fertilisation in flowering plants.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(e) Seed formation occurs after fertilisation. Seeds are formed inside the fruits and then dispersed.
(i)
Name the part of the flower that develops into the seed.
.......................................................................................................................................[1]
(ii)
Name the part of the flower that develops into the fruit.
.......................................................................................................................................[1]
(iii)
State an advantage of seed dispersal.
...........................................................................................................................................
.......................................................................................................................................[1]
(f)
Seed germination occurs when conditions are suitable.
Explain the role of enzymes in seed germination.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
[Total: 13]
Worksheet No: 18/22-23
Date: _____________
Unit: Inheritance
1
Catalase is an enzyme that breaks down hydrogen peroxide inside cells. Red blood cells contain
catalase.
Some dogs have an inherited condition in which catalase is not produced. This condition is known
as acatalasia and it is caused by a mutation in the gene for catalase.
(a) Define the terms gene and gene mutation.
gene...................................................................................................................................
...........................................................................................................................................
gene mutation....................................................................................................................
...........................................................................................................................................
[2]
(b) A geneticist was asked to investigate the inheritance of acatalasia in dogs.
The normal allele is represented by B and the mutant allele is represented by b.
The geneticist made the diagram in Fig. 3.1 to show the inheritance of acatalasia in a family
of dogs. The shaded symbols indicate the dogs with acatalasia.
normal male
1
2
3
normal female
male with acatalasia
4
5
female with acatalasia
Fig. 3.1
(i)
State the genotypes of the dogs identified as 1, 2 and 3 in Fig. 3.1.
1 .............................................................................................................................
2 .............................................................................................................................
3 .............................................................................................................................
[3]
(ii) The geneticist crossed dog 4 with dog 5. Approximately half of the offspring had
acatalasia and half the offspring did not have acatalasia.
Complete the genetic diagram to show how this is possible.
dog 4
dog 5
parental phenotypes
normal
has acatalasia
parental genotypes
.............
.............
gametes
..........
,
..........
+
..........
Punnett square
offspring genotypes................................................................................................
offspring phenotypes ............................................................................................................ [3]
(iii) State the name given to the type of cross that you have completed in (b)(ii).
................................................................................................................................
[1]
[Total: 9]
2
Anthocyanin is a red pigment found in carnation flowers. Some carnation plants have a gene for
making anthocyanin.
(a) Carnation plants show co-dominance for the anthocyanin gene. There are two alleles:
•
FA – allele for anthocyanin pigment (red flowers)
•
FN – allele for no anthocyanin pigment (white flowers)
(i)
State the genotype of a carnation plant that is heterozygous for this gene.
................................................................................................................................
[1]
(ii) Describe the phenotype of a heterozygous carnation plant for this gene.
................................................................................................................................
................................................................................................................................
[1]
(iii) The breeder crossed a FAFN carnation plant with a FAFA carnation plant. Predict, using
a genetic diagram, the proportion of pure breeding carnation plants in the offspring.
gametes

FAFN
parental genotypes
...........
...........
+
FAFA
...........
...........
Punnett square
offspring genotypes .............................................................................................
offspring phenotypes ...........................................................................................
proportion of pure breeding carnation plants .......................................................
[4]
[Total: 13]
3
(a) Sex in cats is determined in the same way as in humans.
Complete the diagram below to show how sex is determined in cats.
male cat
female cat
female cat (XX)
gametes
X
X
......
male cat
(. ....... )
......
offspring ratio ..................................................................................................................................... [3]
(b) A scientist investigated the inheritance of fur colour in cats.
The gene for coat colour is located on the X chromosome. The gene has two alleles:
•
B black
•
b orange.
The X chromosome with the allele for black is represented by XB.
The X chromosome with the allele for orange is Xb.
A female cat can be a mixture of these colours, described as calico.
Fig. 3.1 shows the inheritance of this condition in a family of cats.
1
orange male
2
black male
calico female
orange female
3
4
5
6
7
Fig. 3.1
black female
(i)
State the genotypes of cats 1, 4, and 5 in Fig. 3.1.
cat 1 .......................................................................................................................
cat 4 .......................................................................................................................
cat 5 ........................................................................................................................................ [3]
(ii) Coat colour in cats is an example of discontinuous variation.
Explain why coat colour is an example of discontinuous variation.
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
................................................................................................................................
[3]
[Total: 9]
4. In tulip plants, the petals can have markings called flecks.
There are two alleles for flecks in tulip plants: with flecks F; and without flecks f.
(a) Explain the meaning of the term dominant allele.
...................................................................................................................................................
............................................................................................................................................. [1]
(b) A tulip grower crosses two tulip plants.
He finds that 76 of the offspring have petals with flecks and 23 of the offspring have petals
without flecks.
(i)
Complete the genetic diagram to explain this result.
parental genotypes
…………………
X
…………………
parental phenotypes
…………………
X
…………………
gametes
....
....
X
....
....
offspring genotypes
……………………………
……………………………
offspring phenotypes
petals with flecks present
petals without flecks
[5]
(ii)
The tulip grower wants to produce a pure-breeding variety of tulips with petals without
flecks.
State the genotypes of the parent plants he should use to produce tulip plants without
flecks. Explain your answer.
parental genotypes
…………………
X
…………………
explanation ........................................................................................................................
...........................................................................................................................................
..................................................................................................................................... [2]
5. (a) Sickle cell anaemia is an inherited disease. The gene for haemoglobin exists in two forms,
HbN and HbS. People who are HbSHbS have the disease and experience symptoms including
fatigue and extreme pain in their joints. People who are HbNHbS are carriers of the disease
and may have mild symptoms, if any at all.
(i)
Table 2.1 shows four genetic terms.
Complete Table 2.1 by stating a specific example, used in the paragraph above, of each
genetic term.
Table 2.1
genetic term
example used in the passage
an allele
a heterozygous
genotype
a homozygous
genotype
phenotype
[4]
(b) The gene for haemoglobin exists in two alternative forms:
A
HS
H
codes for the normal form of haemoglobin;
codes for the abnormal form of haemoglobin.
(i) State the name for the alternative forms of a gene.
[1]
(ii) A child has sickle cell anaemia. The parents do not have this disorder.
Complete the genetic diagram to show how the child inherited the disorder.
Use the symbols HA and HS in your answer.
parental phenotypes
normal

normal
parental genotypes
HAHS

HAHS
+
gametes
child’s genotype
...................
child’s phenotype
sickle cell anaemia
[2]
(iii) The parents are about to have another child.
What is the probability that this child will have sickle cell anaemia?
[1]
6. (a) The production of human gametes involves the type of nuclear division known as
meiosis.
State two reasons why meiosis is suitable for gamete production.
1
2
[2]
(b) The sex of a human fetus is determined by the sex chromosomes, X and Y.
Fig. 5.1 shows the determination of sex in four different examples.
Examples 3 and 4 show sex determination in twins.
example
gametes
zygote
cell from a fetus
1
X
+
X
XX
XX
2
X
+
Y
XY
XY
XX
X
+
X
XX
XX
X
+
X
XX
XX
X
+
X
XX
XX
Fig. 5.1
(i)
Use 5.1 to explain how the sex of a fetus is determined.
[2]
(ii) Examples 3 and 4 show two ways in which twins are formed.
The twins in example 3 are identical.
Use Fig. 5.1 to explain why.
[2]
(c) During the development of a fetus, different genes are expressed at different
times.
Explain what is meant by the term development.
[2]
(d) One of the genes that controls the ability of blood to clot is found only on the
Xchromosome.
XH represents an X chromosome with the dominant allele for normal blood clotting.
Xh represents an X chromosome with the recessive allele which causes the blood to
clot slowly.
The Y chromosome is small and does not have the gene for blood clotting.
Here is a list of four genotypes.
XHXH,
XHXh,
XHY,
XhY
Choose the genotype from the list that matches each of the following:
●
gives a phenotype of long clotting time;
●
is heterozygous;
●
is homozygous.
[3]
(e) Haemophilia is a rare genetic condition in which the blood clots very slowly.
In the USA, haemophilia affects 1 in 5000 male births each year. In some cases these
births occur in families where the condition has not occurred before.
Explain how boys can have haemophilia when the condition has not previously existed
in their family.
[2]
[Total: 13]
Worksheet No: 19/22-23
Date: _____________
Unit: 18. Variation and Selection
1
Reed warblers are small birds that migrate over long distances between western Africa and
northern Europe.
Fig. 5.1 shows a reed warbler, Acrocephalus scirpaceus.
Fig. 5.1
(a) State three characteristic features of birds that are visible in Fig. 5.1.
1
2
3
[3]
A study was carried out in Sweden into the effects of natural selection on wing length in
reed warblers.
The wings of young reed warblers reach their maximum length a few days after leaving the
nest.
At this age the wing length in millimetres of each bird was recorded. Each bird was
identified by putting a small ring around one of its legs.
When the birds were caught in net traps as adults, the information on the rings was used to
identify specific birds and their ages.
The length of time between ringing and trapping was recorded for each bird that was
identified before it was released.
The mean age at trapping was calculated for birds with each wing length.
The results are shown in Table 5.1.
Table 5.1
wing length at ringing /
mm
63 or less
64
number of birds
trapped
24
mean age at trapping /
days
253
72
256
65
1
297
66
1
346
67
1
349
68
1
270
69
66
237
70 or more
23
199
total = 771
(b) (i) Explain why wing length is an example of continuous variation.
[2]
(ii) Suggest a feature of reed warblers, other than wing length, that shows
continuous variation.
[1]
2. Fig. 4.2 shows a flower of Lilium polyphyllum, a lily that grows
3. in the Himalayan mountains.This species is cross-pollinated by insects.
Fig. 4.2
(b) Plants of this species that grow at low altitudes produce flowers 60
days before the plants ofthe same species that grow at high altitudes.
(i)
Suggest one environmental reason why lilies that grow at lower altitudes flower earlier
than the lilies at higher altitudes.
.......................................................................................................................................[1]
(ii)
Explain why flowering time is an example of continuous variation.
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.......................................................................................................................................[2]
(b) Scientists think that plants of L. polyphyllum growing at high altitudes may evolve into a new
species.
Explain how natural selection could lead to the evolution of a new species of lily.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[5]
3
Fig. 6.1 shows Soay sheep on St. Kilda, a group of small remote islands off the coast of
Scotland. These islands experience extreme conditions of cold, wind and rain.
Sheep were introduced to the islands thousands of years ago and the Soay sheep are
descended from them.
The islands of St. Kilda have been uninhabited by people since 1930. The sheep are now
left unfarmed and in their natural state.
Fig. 6.1
(a) The populations of Soay sheep on St. Kilda show much more variation in their
phenotype than modern breeds of sheep.
Explain, by using an example from Fig. 6.1, what is meant by variation in their
phenotype.
[2]
(b) Scientists have recorded the numbers of Soay sheep and lambs on St. Kilda for many
years.
Each year between 1985 and 1996, the lambs (young sheep) were caught, marked and
weighed. In some years, the total number of sheep on St. Kilda was lower than in other
years.
Fig. 6.2 shows the frequency of lambs of different body mass in years when the total
number of sheep was low and years when the total number was high.
low population years
120
key
100
lambs that died
80
frequency
of lambs
lambs that survived
for at least a year
60
40
20
0
3–4
5–6
7–8
9–10 11–12 13–14 15–16 17–18 19–20 21–22
body mass / kg
high population years
120
100
80
frequency
of lambs
60
40
20
0
3–4
5–6
7–8
9–10 11–12 13–14 15–16 17–18 19–20 21–22
body mass / kg
Fig. 6.2
(i) Population size has a great effect on the survival of lambs on St. Kilda.
Describe the evidence from Fig. 6.2 that supports this statement.
[2]
(ii) Suggest an explanation for the effect that you have described.
[3]
(c) Soay sheep are adapted to the extreme conditions experienced on St. Kilda.
Explain how natural selection could account for the adaptive features of Soay sheep.
[4]
[Total: 11]
Worksheet No: 21/22-23
Date: _____________
UNIT. 21: ORGANISMS AND ENVIRONMENT
1
The passage describes the feeding relationships between some of the organisms in an
African grassland ecosystem.
The dominant grass species in the African grassland ecosystem are star grass and red oat
grass. Star grass is eaten by antelope species, such as topi and Thomson’s gazelle.
Smaller animals such as mice and grasshoppers also feed on grass. Antelopes are eaten
by predators such as cheetahs, lions and serval cats. Grasshoppers and mice are eaten by
serval cats and tawny eagles. Ruppell’s vulture feeds on dead mammals.
Fig. 1.1 shows part of the food web for this ecosystem.
tawny eagles
.................................
.................................
Thomson’s
gazelle
topi
lions
serval cats
.................................
star grass
grasshoppers
red oat grass
Fig. 1.1
(a) Complete the food web in Fig. 1.1 by writing the names of the organisms in the boxes.
Write your answers in the boxes in Fig. 1.1.
[3]
(b) Name the trophic level of the following species:
star grass
[2
topi
(c)
State the source of energy for the food web shown in Fig. 1.1.
[1]
(ii) State what happens to energy when it leaves an ecosystem, such as the African
grassland.
[1]
(d) Nutrients are recycled in ecosystems but energy is not recycled.
Explain why there are no more than four trophic levels in the ecosystem shown in
Fig. 1.1.
[3]
(e) Fish, such as salmon reared in fish farms, are fed on high protein food made from
animals. When eating this food, these fish are feeding as secondary consumers.
Discuss the disadvantages of farming fish, such as salmon, for human food.
[3]
2
he brown plant hopper is a serious insect pest of rice. Spraying with pesticides is a common
way to control it. However, brown plant hoppers have become resistant to pesticides.
Fig. 6.1 shows the effect of spraying pesticides against populations of this insect pest.
1200
1100
1000
900
800
700
mean number
of brown plant
hoppers per m2
600
500
400
300
200
100
0
0
10
20
30
40
sprays with pesticide
50
60
70
80
days after
transplanting rice
Fig. 6.1
(a) Define the term population.
[2]
(b) Use Fig. 6.1 to describe the effect of pesticides on populations of the brown plant
hopper.
[3]
(c) Some pesticides used against insects kill them on contact. Others are systemic
pesticides.
Explain how these systemic pesticides kill insects.
[2]
(d) As an alternative to spraying pesticides, some farmers use predatory animals, such as
the hunting spider, Lycosa pseudoannulata, to control brown plant hoppers.
During an investigation into the effectiveness of this method, brown plant hoppers were
put into cages in rice fields. The plant hoppers could not leave the cages but were able
to feed. Predators, such as hunting spiders, could enter some of the cages to feed.
Fig. 6.2 shows the change in numbers of brown plant hoppers in these cages over a
period of time.
6000
5000
cages c
to predators
4000
mean number
of brown
plant hoppers
per cage
3000
2000
1000
cages open
to predato
0
0
10
20
30
time / days
Fig. 6.2
40
50
Use the information in Fig. 6.2 to explain the advantages of using predators, such as
spiders, to control brown plant hoppers.
[3]
(e) Rice growing has involved the destruction of forests.
Describe the long-term effects of deforestation on the environment.
[4]
[Total: 14]
(f) Suggest why the numbers of L. bulgaricus do not start to increase until after the
increase in the numbers of S. thermophilus.
[2]
2
(a List four chemical elements that are found in proteins.
1.
2.
3.
4.
[4]
Fig. 6.1 is a photograph of some root nodules from a pea plant, which is a type of legume.
Fig. 6.1
(b) Nodules like those in Fig. 6.1 develop on the roots of pea plants and other legumes
when the soil is lacking in nitrate ions.
Explain what happens inside the nodule to help legume plants grow in soils lacking
nitrate ions.
[3]
(c) After the peas have been harvested, the plants are ploughed back into the soil.
Describe what happens in the soil to convert dead plant material into nitrate ions that
plants can absorb.
[6]
(d) Nutrients in the soil can act as a limiting factor for crop growth.
List three other factors that may limit the growth of a crop plant.
Worksheet No: 21/22-23
Subject: Biology
Date: _____________
Chapter 20: Human Influences on Ecosystem
2.
3.
4.
5.
Worksheet No: 20/22-23
Date: ____________
Unit: Chap:21 Biotechnology and Genetic Engineering.
1
(a) Define the term genetic engineering.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[2]
(b) Fig. 6.1 is a flow diagram that shows how insulin can be produced using genetic engineering.
R
L
Q
M
N
O
P
Fig. 6.1
Table 6.1 shows stages in the production of insulin by genetic engineering.
Complete Table 6.1. The first row has been done for you.
Table 6.1
letter from
Fig. 6.1
M
name
chromosomes
description
threads of DNA found in the nucleus
section of DNA removed from human cell
plasmid
type of cell that is genetically engineered
specific chain of amino acids coded by the
section of DNA removed from the human
cell
fermenter
[5]
(c) The genetically engineered cells in Fig. 6.1 reproduce asexually.
Explain the advantages of asexual reproduction for insulin production by genetic engineering.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
...............................................................................................................................................[3]
[Total: 10]
2
Antibiotics are used to treat human diseases.
Many bacteria have become resistant to antibiotics. Some antibiotics can no longer be used
to treat certain diseases.
Samples of bacteria were taken from a person who had an infectious disease. They were
spread onto four Petri dishes of agar (agar plates). Three of these agar plates contained the
antibiotics 1, 2 or 3.
The results are shown in Fig. 2.1.
agar plate contains
no antibiotic
agar plate contains
antibiotic 1
agar plate contains
antibiotic 2
agar plate contains
antibiotic 3
key
bacterial growth
no bacteria
Fig. 2.1
(a) Explain why:
(i) no bacteria grew in the agar plate with antibiotic 2;
[1]
(ii) bacteria grew in the agar plate with antibiotic 3;
[1]
(iii) only a small number of bacteria grew with antibiotic 1.
[2]
(b) Explain why it is important to carry out a test similar to that shown in Fig. 2.1 before
giving an antibiotic to a person infected with a bacterial disease.
[2]
(c) Antibiotic resistance has become a major problem worldwide.
Suggest how the problem of antibiotic resistance can be limited.
[4]
(d) Hormones are used to treat a variety of conditions.
The most common hormonal treatment is the use of insulin to treat diabetes. Most of
the insulin is produced using cells that are grown in large fermenters. These cells have
been genetically engineered to produce human insulin.
Fig. 2.2 shows the stages involved in transferring the gene for insulin from human cells
to bacterial cells.
P
gene from human cell removed from chromosome 11
Q
bacterium produces human insulin
R
plasmid vector enters bacterium
S
gene for human insulin found to be on chromosome 11
T
bacterium divides by binary fission
V
gene for human insulin inserted into a plasmid vector
Fig. 2.2
(i) Put the stages into the correct sequence. Two have been done for you.
S
Q
[1]
(ii) Diabetes is often treated with human insulin that has been produced by genetically
modified cells. In most countries this type of insulin has replaced the insulin that
was prepared from animals.
Suggest the advantages of providing human insulin to people with diabetes rather
than insulin obtained from animals.
[3]
[Total: 14]
Worksheet No: 20/22-23
Date: ____________
Unit: Chap:21 Biotechnology and Genetic Engineering.