MARANDA HIGH SCHOOL
Kenya Certificate of Secondary Education
THE MOCK EXAMINATIONS, 2025
JULY/AUGUST, 2025 TIME: 2 HRS
Name: …………………………………….…….…… Admission No: …………
Stream: ……………….. Signature: ………..........
231/1
BIOLOGY PAPER 1
(THEORY)
FORM 4
INSTRUCTIONS TO CANDIDATES:
Write your name and index number in the spaces provided above.
Answer ALL questions in the spaces provided above.
All workings must be clearly shown where necessary.
Question Maximum score Candidate score
1 - 30 80
This paper consists of 9 printed pages.
Candidates should check the question paper to ensure are printed and no questions are missing.
Page 1 of 12
©The Maranda High School Mock Committee, 2025
1. Name the main target organ of the following hormones: (2mks)
(a) Antidiuretic
(b) Glucagon (1mk)
2. (a) What is Binary Fission? (1mk)
(b) Give two disadvantages of sexual reproduction. (2mks)
3. A sucrose solution was boiled with hydrochloric acid. Sodium hydrogen carbonate was added
and the mixture heated with benedict’s solution. An orange precipitate was formed.
(a) Why was the solution boiled with hydrochloric acid? (1mk)
(b) To which class of carbohydrates does sucrose belong? (1mk)
(c) Name the type of reaction that takes place when:
Simple sugars combine to form complex sugar. (1mk)
(d) State the form in which carbohydrates are stored in animals. (1mk)
4. (a) State two ways in which blood clotting is important to a human being. (2mks)
(b)what are the roles of thrombokinase enzyme during blood clotting? (2mks)
Page 2 of 12
©The Maranda High School Mock Committee, 2025
5. In an experiment, Venna counted 9 cells along the diameter of field of view of a light microscope
measuring 3.0mm. Determine the diameter of one cell in micrometers. (3mks)
6. (a) Name the hormone that stimulate the maturation of the Graafian follicles to release a mature
ovum in female reproductive cycle. (1mk)
(b)Explain why menstruation does not take place after fertilization in human beings. (2mks)
7. Name the branch of biology that involves the study of:
(a) Organisms for the sake of classifying them. (1mk)
(b) Microscopic organisms (1mk)
8. (a) Photosynthesis takes place in two stages. Name the part of chloroplast where the light stage
occurs. (1mk)
(c) How is the dark stage dependent on the light stage of photosynthesis? (2mks)
9. The illustration below represents the base sequence for a section of a nucleic acid.
a) (i) Identify the nucleic acid which is represented by the illustration. (1mk)
(ii)Give a reason for your answer in (a) (i) (1mk)
b) Name the part of the cell where the section of the nucleic acid shown would be used. (1mk)
Page 3 of 12
©The Maranda High School Mock Committee, 2025
10. The diagram below shows part of the gaseous exchange system of a given animal.
a) What is the importance of the bands of chitin observed in the part labelled M? (1mk)
b) How is the part labelled N adapted to its function? (2mks)
11. Explain how the human sperm cell is structurally adapted to perform its function. (2mks)
12. Name two mechanism that hinder self-fertilization in flowering plants. (2mks)
13. Give three functions of diffusion in living organism. (3mks)
14. Give two ways in which seed dormancy benefit a plant. (2mks)
15. The following is part of a kidney nephron.
Page 4 of 12
©The Maranda High School Mock Committee, 2025
(i) Name the process represented by the arrows; (1mk)
(ii) Name the condition necessary for the process named in (a) (i) above to take place. (1mk)
(iii) Identify vessel A. (1mk)
16. State two characteristic features of members of division Bryophyta. (2mks)
17. (a) Give the roles of the following in the stomach.
i) Hydrochloric acid. (1mk)
ii)Mucus (1m)
(b)Name the cells that secrete enzyme pepsin and renin in the stomach. (1mk)
18. (a) Give two functions of the liver to its functions. (2mks)
(b)Explain why insulin is not administered orally. (1mk)
19. (a) What is blood transfusion? (1mk)
(b)State one factor to consider during blood transfusion. (1mk)
20. (a) Give one difference between aerobic and anaerobic respiration. (1mk)
Page 5 of 12
©The Maranda High School Mock Committee, 2025
(b)Give two importance of respiration quotient. (2mks)
21. Name the organisms involved in the following processes.
(i) Nitrification (1mk)
(ii) Denitrification (2mks)
22. Study the diagram below and answer questions that follows;
a) Name the organelle (1mk)
b) State function of the structure labelled A. (1mk)
23. What is the meaning of the following terms as used in ecology. (2mks)
(i) Autecology
(ii) Synecology
24. (a) State two functions of an ovary in a human female. (2mks)
(b)State two advantages of internal fertilization in mammals. (2mks)
Page 6 of 12
©The Maranda High School Mock Committee, 2025
25. The diagram below shows a transverse section of a plant organ;
a) Name the plant organ from which section was obtained. (1mk)
b) (i) Name the class of the plant from which the plant organ was obtained. (1mk)
(ii)Give a reason for your answer in (b) (i) above. (1mk)
c) Name the part labeled x. (1mk)
26. The reaction represented by the equation below occurs in the body.
Enzyme Y
Hydrogen peroxide Oxygen + Water
a) Name enzyme Y (1mk)
b) Name an organ in the body where the reaction occurs. (1mk)
27. The graph below represents the growth of animals in a certain phylum. Study it and answer the
questions that follow;
Page 7 of 12
©The Maranda High School Mock Committee, 2025
a) Name the type of growth pattern shown on the graph (1mk)
b) Identify the process represented by letter B. (1mk)
c) Name the hormone responsible for the process in (b) above. (1mk)
28. State the category of variation into which the following traits fall. (2mks)
(i) Skin pigmentation (1mk)
(ii) Blood group (1mk)
29. Distinguish between hypogeal and epigeal germination. (2mks)
30. State the economic importance of the following metabolic wastes from plants. (2mks)
(i) Papain
(ii) Tannin
Page 8 of 12
©The Maranda High School Mock Committee, 2025
