Biology exam questions

Question 1

Give a reasons why you get the greatest proportion of biomass and energy when eating directly from a primary consumer. (3 marks)

Answer 1

• fewer stages of levels
• less wasted in waste
• less wasted in respiration

Question 2

Describe how animals AND plants are adapted to live in dry conditions such deserts. (6marks)

Answer 2

Animals:
- Humps with fat stores
- decreased surface area to reduce water loss
- Long eyelashes to prevent dust entering eyes on windy day.
Plants:
- Thick wax to reduce evaporation of water
- thick stem to store water
- leaves are spikes reduce water loss
- long roots

Question 3

Most birds sit on their eggs to keep them warm until they hatch.
Megapode birds:
● dig a large hole in sand
● fill the hole with dead plants
● lay their eggs on top of the dead plants
● cover the surface with a thick layer of sand.
(1a)The dead plants in the nest decay. The decaying process helps to keep the eggs warm
for many weeks. Suggest how. (3marks)

(1b)Megapode birds open and close the air vents of the nest at different times of the day.
Suggest reasons why it is necessary to open and close the air vents. (3marks)

Answer 3

(1a) - microorganisms
- respire
- respiration releases heat

(1b) - allows oxygen in
- microorganisms need oxygen
- retains energy when closed.

Question 4

Describe how information passes from relay neurone to motor neurone. (3marks)

Answer 4

• Nerve impulses move across synapse
• releasing chemical
• chemical messenger attaches to motor neurone and the nerve impulse crosses over.

Question 5

suggest why limb abnormalities caused by thalidomide was not recognized in the drug trials .

Answer 5

• Not tested on pregnant animals/ women.

Question 6

Give two reasons why scientist could not decide whether Lamarks or Darwins theory was correct?

Answer 6

• not enough evidence
• inheritance not understood
• ignore other beliefs e.g: religious beliefs

Question 7

Differences in the characteristics of different individuals of the same kind may be a result of?

Answer 7

• genetic variation

- difference in environment

Question 8

what did Semmelweis want people to understand.

Answer 8

• improved hygiene (would stop deaths)

- because we kill bacteria/pathogens.