BUTEREGIRLS'NATIONALSCHOOL
MOCK EXAMS 2025
Kenya Certificate of Secondary Education
NAME________________________________ ADM NO___________ CLASS__________
231/2
BIOLOGY
PAPER 2
TIME: 2 HOURS
Biology
Paper 2
INSTRUCTIONS TO CANDIDATES:
Write your name and admission number in the spaces provided.
Sign and write the date of examination.
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 question 7 or 8 in the spaces provided.
Check and ascertain that no questions are missing.
For Examiner’s Use Only:
SECTIONS QUESTION MAXIMUM SCORE CANDIDATES SCORE
A 1 8
2 8
3 8
4 8
5 8
B 6 20
7 20
8 20
TOTAL SCORE 80
SECTION A (40 MKS)
Answer ALL the questions in this section in the spaces provided on the question paper.
1. The diagram represents bones at joint in the hind limb of a mammal.
(i) Name the bones labeled (3mks)
X……………………………………………………………………………………..………………………………
Y…………………………………………………………………………………..…………………………………
Z……………………………………………………………………………………..…………..…………………..
(ii) a) name the substance found in the place labeled W (1mk)
…………………………………………………………………………………..…………………………………
b) State the function of the substance named in (B) I above. (1mk)
……………………………………………………………………..……………………………….………………
(iii) name the structures that joins the bones together at the joints
(1mk)
………………………………………………………………………………………………………….…………
(iv) state the difference between ball and socket joints and the one illustrated in the diagram above (1mk)
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
(v) name the structure at the elbow that performs the same function as patella (1mk)
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
2. The photograph below shows components of blood from a ruptured blood vessel. Study it and answer the
questions that follow.
a) Suggest the identity of the above blood vessel if a lot of digested food substances were found dissolved in
part T. (1mk)
………………………………………………………………………………………………………………………
b) Identify cell U and suggest its function. (2mks)
………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………….
c) i) name three types of antigens that are likely to be present on the surface of the membrane of cell V
(3mks)
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
ii) Where in the human body is cell V produced? (1mk)
……………………………………………………………………………………………………’…………………
d) What role does structure W play in blood clotting? (1mk)
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
3. (a) During a lesson, students observed the structure of a bat and human forelimbs to determine their
evolutionary relationship.
(i) State the term used to describe the structure of the limbs observed by the students. (1mk)
……………………………………………………………………………………………………………….
(ii) Name the type of evolution illustrated by the structure of the limbs observed. (1mk)
………………………………………………………………………………………………………………
(iii) What evidence of evolution is illustrated by the limbs. (1mk)
……………………………………………………………………………………………………..
…………
(iv) State the significance of the type of evolution illustrated by the limbs. (1mk)
……………………………………………………………………………………………………………..……….
(b) Explain how comparative embryology is an evidence for organic evolution in vertebrates. (2mks)
……………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………
(c)Explain the theory of evolution by natural selection. (2mks)
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………….
4. In an experiment a group of students set up the test tubes as shown below
a) What was the aim of the experiment (1mk)
…………………………………………………………………………………………………….
………….
b) Why was pyrogallic acid included in the gas jar A (1mk)
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
c) What results would you expect in each of the gas jars A and B (2mks)
A……………………………………………………………………………………………………..…………
B…………………………………………………………………………………………………………………
d) state two artificial ways of breaking seed dormancy (2mks)
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
……………………………………………………………………………………………………..………..
e) Name two hormones that bring about rapid cell division in plants. (2mks)
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
…………
5. Haemophilia is a genetic disease which is transmitted through a recessive gene linked to the X chromosome.
The normal gene may be represented by H and the gene for haemophilia may be represented by h.
(a) A woman who is a carrier for haemophilia married a normal man. Work out the expected genotypic and
phenotypic ratio of their children. (Show your working.) (6mks)
(b) Hemophilia is more common in men than in women. Explain? (2mks)
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
………………………………………………………………………………………………………………
……………………………………………………………………………………………………………….
.
SECTION B(40 MKS)
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 the effect of temperature on the rate of reaction catalyzed by
salivary amylase. The pH was maintained and the results are shown in the table below
Temperature oC 5 10 20 25 30 35 38 45 50
Rate of reaction (Arbitrary units) 0.3 0.5 1.2 2.0 3.5 4.8 4.8 2.5 0.8
(a) Using the same axes, draw a graph of rate of reaction against temperature (7 marks)
b) What is the optimum temperature for this enzyme? (1mk)
………………………………………………………………………….…………………………………….
c) At what temperature was the rate of reaction 1.4? (1mk)
…………………………………………………………………………………………………………………..
d) Account for the shape of the graph between:
i. 5oC and 350C (2mks)
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
…………
ii. 380C and 500 C (3mks)
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………….……
e) How is the hydrochloric acid from the stomach neutralized and where does this neutralization occur?(2mks)
…………………………………….….
……………………………………………………………………………………………………………………….
.
………………………………………………………………………………………………………………………
…………………….…………………………………………………..……..
f) Name one digestive enzyme in humans that works best in acidic conditions. (1mk)
…………………………………………………………………………………………………..…………………
g) State two factors that cause enzyme denaturation (2mks)
………………………………………………………………………………………………………………………
……………………………………………………………………………………………..
…………………………
h) Name two factors that determine the amount of energy a human being requires in a day (2mks)
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
7. a) Describe the role of each of the following hormones in human menstrual cycle.
a. Oestrogen. (2mks)
ii. Progesterone (3mks)
iii. Lutenising hormone (3mks)
iv. Follicle stimulating hormone (2mks)
b) Explain features and mechanisms that hinder self-pollination and self-fertilization (10mks)
8. Describe the structure and functions of various parts of the human ear (20mks)
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
………………………………………………………………………………………………………………………
…
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
