S4 BIOLOGY REVISION QUESTIONS
1
a) What is meant by
i) Environmental degradation?
ii)Global warming
b) The level of carbon dioxide in the atmosphere is changed largely by man’s
activities such as defforestation.
Describe how:(i) levels of carbon dioxide in the atmosphere can be maintained.
(ii) Energy flows between organisms during the carbon cycle
c) Suggest and explain any man activities that may lead to
i) Water pollution
ii) air pollution
iii) Land pollution
d) What are the remedies to these activities to lessen the effect of pollution?
2. With reasons and necessary precautions describe how the population of the following can be
determined.
i)
ii)
iii)
Grasshoppers
Paspallum in an open grassland
Hippopotamus
b) Name and explain three biotic factors that affect the size of a population of organisms
3. a) The following organisms were observed in a game park:
cheetah, grass, chameleon, marabou stock, lion, vulture, snakes, lizards, grasshoppers,
i)
ii)
Iii)
4.
Draw a food web to show the feeding relationships.
Name one scavenger that forms part of the food web.
Draw any two food chains made of five organisms.
The data below shows the pH of an aquatic habitat varied within a period of 24 hours.
time in hours
pH
24(mid-night)
7.8
06(dawn)
7.6
12(mid-day)
7.9
18(dusk)
8.0
a) Draw a graph of variation of pH with time of day.
b) Describe the variation of pH with time of day.
c) What causes the (i) decrease in pH of the water from mid night to dawn?
(ii) increase in pH of the water from dawn to dusk?
24(mid-night)
7.8
(iii) decrease in pH from dusk to mid night?
5.
Describe an experiment to show that carbon dioxide is produced during aerobic respiration by a
green plant
6.
A student performed an experiment to investigate the effect of size on the rate of heat loss in
Mammals using test tubes of different sizes A and B. The following results were obtained:
time in minutes
0
1
2
3
4
5
6
7
8
Temperature of the water in oC
in:
A
70
63
58
55
52
48
46
45
43
70
68
66
60
57
55
53
52
51
B
(a) Represent the above results graphically ,using the same axes.
(b) State with a reason which of the two test tubes represents (i)a larger mammal
(ii) a small mammal
(c) Explain why the respiratory rate & other metabolic reactions in a small mammal should be
faster than the larger one.
(d) Which of the two mammals (i) eats more than its body mass?
(ii) eats a small fraction of its mass in food?
(e) Using the above information explain the disadvantage of (i) the small size
(ii) large size in a mammal
7.
(a) What is the importance of water to plants?
(b) Describe how water is obtained from the soil and reaches the leaves to the atmosphere.
8.
(a)define: (i) diffusion
(ii) osmosis
(iii) active transport
(b) State the importance of the following in organisms (i) diffusion
(ii) osmosis
(iii) active transport
(c) describe an experiment to demonstrate osmosis in living cells.
9.
(a) Describe the adaptaions of a dicotyledonous leaf for photosynthesis.
(b) What is the importance of photosynthesis?
(c) State: (i) the raw materials for photosynthesis
(ii) the products of photosynthesis.
(d) Write down the equation for photosynthesis.
10.
What would be the effect of the following conditions on the amount of water excreted by the
Kidney?
(a)
(b)
(c)
(d)
11.
Drinking a lot of water
A high external temperature
Eating very salty food
Doing very strenuous exercise
The table below shows the effect of temperature on the rate of respiration of a small animal
Determined using a respirator. The rate of respiration is expressed as the volume of oxygen
consumed per kg of body mass per hour.
Rate of respiration (cm3/kg)/hour.
0
50
Temperature
0
10
(a) Draw a graph to represent the above information.
(b) Describe the changes shown in the graph.
(c) Explain the changes shown in the graph
100
20
200
30
400
40
250
50