Biology A Level GCE Past Question Paper 2018

Biology A Level GCE Past Question Paper 2018 cameroon

1. What do you understand by Biomolecules?


b) Comment on the impotance of biomolecules in living organisms.

c) How are nucleic acids different from the other biomolecules?

(2, 12, 6 marks)
(Total = 20 marks)

2. a) Define anaerobic respiration.

b) Using suitable examples of organisms, describe the three possible anaerobic pathways.

c) Draw a large labelled diagram of a mitochondrion. Annotate it to show its functions in respiration.

d) Analyse the role of cofactors in respiration.

(2, 6, 8, 4 marks)
(Total= 20 marks)

3) a) What do you understand by translocation?

b) Compare and contrast transport in plants and animals.

c) Describe an experiment to proof that the phloem is the site of translocation.

3, 12, 5 marks)
(Total= 20 marks)

4. a) What is meant by the following ecological terms:

Conservation.

Biodiversity.

Endangered species.

b) 
List the main Biomes in the universe.

Describe four key physical factors that affect the distribution of organisms in an ecosystem.

c) 
What factors contribute to the extinction of a particular species.

How may the extinction of species of organisms be reduced?

(6, 8, 6 marks)
(Total = 20 marks)

5. a) Distinguish between the following terms as used in growth:

Isometric and Allometric growth.

Limited and unlimited growth.

b) 
How is the growth of an individual related to genes?

What other factors affect growth?

c)
Describe the role of the following endocrine glands in the growth of humans.

Thyroid gland

Pituitary gland

(8, 4, 8 marks)
(Total= 20 marks)

6. Make a large labeled diagram of the mammalian ear.

b) Trace the events that occur in the ear that enable you to hear the sound of moving vehicles out door.

c) How is the pitch of the sound determined?

d) Describe the causes of two named ear defects.

(6, 6, 4, 4 marks)
(Total = 20 marks)

7. a) Define the following terms:

Oxidative phosphorylation

Compensation point

Photorespiration

b) Describe the light independent stage in C4 plants.

c) Outline the advantages of growing C4 plants instead of C3 plants.

(8, 10, 2 marks)
(Total= 20 marks)

8. a) What are lethal genes?

b) In a series of breeding experiments using mice, the following crosses wère made

- A yellow fur coat female mouse was mated with a grey fur coat male.

A litter (offspring) of 12 mice was produced, 6 yellow fur coat and 6 grey fur coat.

- A yellow fur coat female mouse was mated with a yellow fur coat male.
The litter (offspring) had 3 grey fur coat and 6 yellow fur coat.

When two grey fur coat mice were mated, the litter had all grey mice.

Given that the allele for fur coat is not sex-linked, use suitable genetic symbols to explain the
above crosses.

Explain why these ratios deviated from the expected Mendelian ratios.

(3, 17 marks)
(Total=20 marks)