Human Biology Past GCE Questions A/L 2023PHCS
Human Biology Past GCE Questions A/L 2023
Q1. (a) Explain how the information coded in DNA is used to make proteins (12 marks)
(b) How is the synthesis of protein regulated by enzyme induction and enzyme repressions? (8 marks).
Q2. (a) With the aid of suitable examples, distinguish between metagenesis and alteration of generation (4 marks).
(b) What role is played by metamorphosis in the life cycle of an insect? (4 marks)
(c.) Show how the tapeworm is adapted to its parasitic mode of life? (6 marks)
(d) Which features enable the goat, sheep, and man to be placed in the same group? (6 marks)
Q3. (a) What role is played by each of the following in digestion?
(i)Salivary gland (4 marks)
(ii) Oxyntic glands (9 marks)
(b) How is the structure of the ileum suited to its function of absorption? (7 marks)
Q4. (a) With the aid of a diagram, describe the cardiac cycle (10 marks)
(b) What role is played by the lymphatic system in the defense mechanisms of the body against infections? (10 marks)
Q5. (a) Outline the sequence of events that occur during the formation of a nerve impulse. (9 marks).
(b) How are impulses transmitted from one neuron to another? (7 marks)
(c) Briefly explained how the hypothalamus controls the pituitary glands in coordination (4 marks).
Q6. (a) Trace the pathway of energy flow from the sun to decomposers in named ecosystems. (7 marks).
(b) What role is played by bacteria in the recycling of nitrogen within ecosystems? (8 marks)
(c.) In what ways can inhabitants in large towns and cities suffer from excessive noise? (5 marks).
Q7. A cocoa farmer planted two species of cocoa plants. The cocoa plants with green and smooth pods were dominant over those with red and rough pods.
Across between a green and a smooth pod cocoa plant and that with the red rough pod, the plant gave all the F1 offspring having green and smooth pods.
When the F1 was allowed to cross with the other cocoa plants with red and rough pods, the following results were obtained.
380 were green and smooth pods of cocoa plants
63 were green and rough cocoa plants
368 were red and rough cocoa plants
69 were red and smooth cocoa plants.
(a). Use genetic symbols to illustrate these crosses (16 marks)
(b). Calculate the crossover value of the above crosses (2 marks)
(c.) What is the significance of the crossover value? (2 marks)
Q8. (a) Distinguish between:
(i)A culture and culture medium (2 marks)
(ii) Batch and continuous culture (2 marks)
(b) Show how humans have exploited the activities of microorganisms to produce:
(i) A named antibiotics (8 marks)
(ii) Beer (8 marks)
Check Out: Human Biology Past GCE Questions O/L 2023