Term 3 Form 2 Biology Exam Paper

FORM TWO BIOLOGY

1.State two adaptations of the alveolus to its functions. (2mks)

2.A mango tree is known as mangifera Indica

.(a) Identify two mistakes made in the writing of the name (2mks)

(b) What is the scientific naming called? (1mk)

State the role played by the following substance in digestion.

(i) Hydrochloric acid (2mks)

(ii) Bile salts (2mks)

.4 .The chemical equation below represent a reaction that occurs in cells.

2C₅₁H₉₈O₆ + 145O₂ 102CO₂ + 98H₂O

(a) Calculate the respiratory quotient (RQ) (2mks)

(b which is the respiratory substrate in (a) above? (1mk)

5) Define the meaning of the following terms

(a) Entomology (1mk)

(b)Genetics(1mk)

6) a) Differentiate between transpiration and guttation (2mark)

b) State two conditions that are necessary for opening of the stomata (2mark)

7 a)Some form one students wanted to collect the following animals for study in the laboratory. State the suitable apparatus they should use.

i)Flying insects (1 mark)

ii) Crawling stinging insects (1mark)…

iii) Small animals from tree barks (1mark

b)list the salivary glands found in human beings (3marks)

8) (a) The following are characteristics of a certain animal dentition; large curved and sharply

Pointed canines, small closely fitting incisors, narrow molars and premolars with cusps

(i) Identify the likely mode of feeding in this animal (lmk)

(ii) State three adaptations of the three types of teeth to the mode of feeding identified in (i) above 3mks)

9) a) State two advantages which a constant body temperature gives mammals and birds over the other animals (2 marks)

b) How does the body size affects heat loss in an animal (1mark)

10 ) The diagram of the Nucleolus of a liver cell of a rat in an electron micrograph was 8.0 mm. Calculate the actual diameter of the Nucleolus in micrometers given the magnification was X16000. (2 marks)

11) Explain why tracheids are not efficient in transporting water up the plant.(1mark)

12) some form two students run round the school football field five times continuously. Explain what they experience in their

a) Respiratory system. …
b) Heart…
c) Arteries

13.

a) An experiment was set up as shown below.

(a) A student blew air in and out through point X. Using arrows indicate on the diagram how air gets in and out of the set up. (2mks)

(b) (i) In which of the test tube would lime water turn milky first. (1mk)

(ii) Give a reason. (1mk)

14) In an experiment to investigate the action of pepsin on egg albumen, equal amount of

pepsin were added to equal amount of egg albumen in different test –tubes. The test-tubes

were placed in water bath at different temperature. The graph below shows the time taken

for the enzymes to digest protein at each temperature.

(a) A student blew air in and out through point X. Using arrows indicate on the diagram how air gets in and out of the set up. (2mks)

(b) (i) In which of the test tube would lime water turn milky first. (1mk)

(ii) Give a reason. (1mk)

14) In an experiment to investigate the action of pepsin on egg albumen, equal amount of

pepsin were added to equal amount of egg albumen in different test –tubes. The test-tubes

were placed in water bath at different temperature. The graph below shows the time taken

for the enzymes to digest protein at each temperature.

(a) What is the optimum temperature for enzymes? (1mk)

(b) Account for the time taken to digest egg albumen at 60⁰C. (2mks)

(d) State three other factors that affect enzyme controlled reactions. (3mks)

15) In a physiological experiment, starch, protein, diastase and sodium chloride were added to water and put inside a visking tubing. The visking tubing was then placed in a water bath maintained at a temperature between 35 – 40°C. The set up was as shown in the diagram below.

Diagram available on the paid for paper

Contents in	At the start of experiment	After 1 hour
Visking tubing	i) Solution tastes salty	Solution tastes salty
	ii) Visking tubing is not firm	Visking tubing is firm
	iii) After boiling with Benedicts solution, solution remains blue	After boiling with Benedicts solution the solution turns brown
	iv) On addition of solution hydroxide followed by copper sulphate solution to the solution, the colour changes to purple	On addition of sodium hydroxide followed by coppers sulphate to the solution, the colour changes to purple
Beaker	i) Water is tasteless	Solution tastes sweet/salty
	ii) After boiling solution with Benedicts solution, Blue colour remains	After boiling solution with Benedicts solution, colour turns to brown
	iii) On addition to sodium hydroxide followed by copper sulphate solution, colour remains blue	On addition of sodium hydroxide followed by copper sulphate solution, colour remains blue

Name the process by which salt moved into the water in the beaker from the visking

tubing. l mark)

b) i) Name the food substance responsible for the brown colour observed after 1 hour both inthe beaker and visking tubing when solutions are boiled with benedicts solution. (l mark)

ii) Account for the observation in (b i) above. (3 marks)

c) i) Name the food substance tested with sodium hydroxide followed by copper sulphate

solution(s) (1 mark)

ii) Account for the absence of the food substance named in (c i) above in the beaker after 1 hour. (l mark)

d) After one hour the visking tubing was firm. State the term used to describe this

(1 mark)

16) a) Distinguish between natural and acquired immunity (l mark)

b) Define the term allergy (l mark)

c) The chart below shows the blood clotting mechanism

i) Name the blood cells represented by X (1mark)

ii) The end product of the mechanism represented by Z (1 mark)

d) Explain how the following environmental factors increase the rate of transpiration.
i) Temperature (2 marks)
ii) Humidity (1 mark)

iii) Atmospheric pressure (1 mark)

The structures below represent specialized cells in man.

a) Identify structure X, Y and

X ………………………………        (lmark)
Y         …………………………(1 mark)
Z          ………………(1 mark)

b) Give a reason for your answer for X in (a) above. (1 mark)

c) Give two adaptation of Z to its function. (2 marks)

d) What is tissue fluid? (2 marks)

18) a) Describe how urea is formed (5 marks)

b) Describe the path followed until it is eliminated from the body (15 marks)