NAME:_______________________________________Index No:__________________________
SCHOOL:_____________________________________ DATE:___________________________
SIGNATURE:__________________________ CLASS:_____________ ADM NO:___________
231/2
BIOLOGY PAPER 2
THEORY
END OF TERM 1, 2024
TIME: 2 HOURS
INSTRUCTIONS TO CANDIDATE:
- Write your name and index number in the spaces provided above.
- This paper consists of two sections; A and B.
- Answer ALL the questions in section A in the spaces provided.
- In section B, answer questions 6 (compulsory) and either questions 7 or 8 in the spaces
provided after question 8.
For Examiner’s use only
SECTION QUESTIONS MAXIMUM SCORE CANDIDATE SCORE
1 8
2 8
A
3 8
4 8
5 8
6 20
B 7 20
8 20
TOTAL SCORE 80
1
SECTION A(40 MARKS)
1. The diagram below represents a plant cell organelle;
a) Name the organelle (1mk)
b) In which of the labeled parts does carbon(IV)oxide fixation occur? (1mk)
c) Name the parts labeled A and B and state how each is adapted to its function(4mks)
A
d) Explain what would have happened to the structure labeled X had the plant been kept in
darkness for 48 hours (2mks)
2. A group of students set up an experiment as shown below. The experimental set ups were left
for 20 minutes.
2
The observation after 20 minutes were as shown in the table below;
Set up Observations
Inside tubing Outside tubing
A Blue black colour Colour of iodine
B Colour of iodine Colour of iodine
a) State the process being demonstrated in this experiment. (1mk)
b) Explain the results in set up A; (4mks)
c) Why was there no blue black colour inside the visking tubing in set up B; (2mks)
3. The diagram below represents the nitrogen cycle;
3
a) Name the process labeled; (2mks)
i) L
ii) N1 and N2
b) Name the organisms that convert M into nitrates. (1mk)
c) Name the organism in plants which promotes process K(1mk)
d) State the relationship between the organisms stated in (c) above and the plant;(1mk)
e) How would excess pesticides in the soil interfere with process K;(2mks)
f) If F1 is nitrogen fixation by free-living bacteria, F2is nitrogen fixation by what? (1mk)
4. The diagram below shows a mould of the genus Rhizopus;
4
a) Name the kingdom to which it belongs; (1mk)
b) Name the structures labeled A and B (2mks)
A
c) Give the functions of the structure labeled B (2mks)
d) How do the structures labeled B differ from plant roots(1mk)
e) Give two ways in which members of the kingdom you stated in (a) above are useful to man.
(2mks)
5. (a) Name the two types of variations. (2mks)
(b) In a garden with pea plants, 625 plants had tall stems while 205 had short stems in the F 2
generation;
5
i) Work out the ratio of tall to short plants (give your answer correct to the nearest whole
number) (1mk)
ii) Using letter T to represent the dominant gene, work out a cross between an F 1 offspring and a
short plant. (4mks)
iii) What is the genotypic ratio from the cross in b (ii) above (1mk)
SECTION B:
Answer question 6 (compulsory and either question 7 or 8 in the spaces provided after question 8:
6. An experiment was carried out to investigate transpiration and absorption of water in a certain
plant species. The plants were potted and supplied with adequate water. The amount of water
lost and absorbed was determined. The results are shown in the table below;
Time of the day Amount of water in grams
Transpiration Absorption
0700-0900 30 15
0900-1100 40 25
1100-1300 48 34
1300-1500 56 45
1500-1700 40 50
1700-1900 25 40
1900-2100 15 28
2100-2300 10 21
6
a) Using the same axes, plot graphs to show transpiration and absorption of water in grams against
time of the day. (7mks)
7
b) At what time of the day was the amount of water the same for transpiration and absorption;
(1mk)
c) Explain the shape of the graphs of:-
i) Transpiration (3mks)
ii) Absorption (3mks)
d) Suggest what would happen to transpiration and absorption of water if the experiment was
continued for another 2 hours; (2mks)
e) Name two factors and explain how they would affect transpiration and absorption at any given
time. (4mks)
7. (i) Describe the process of fertilization in flowering plant. (10mks)
(ii) How is the human male reproductive system adapted to its functions? (10mks)
8. (i) Explain the methods of excretion in plants. (10mks)
(ii) Explain how the nephron is adapted to its functions. (10mks)
