9700/42

Biology 9700/42May/June 2020

Cambridge A-Level · worked solutions for every part, with the mark scheme

10
questions
100
marks
120
minutes

Topics Genetic Technology · Inheritance · Homeostasis · Classification, Biodiversity and Conservation · Selection and Evolution · Control and Coordination · +2 more

Q1HomeostasisInheritanceFree sample
(a)

The enzyme alanine transaminase (ALT) is found in the liver. The function of ALT is to convert the amino acid α\alpha-ketoglutarate into another amino acid, glutamate.

Suggest why the liver may need to convert one amino acid into another.

1M
(b)

Tumours can form in the liver.

Explain how a liver tumour develops.

2M
(c)

ALT can leak into the blood from liver tumour cells.

An increase in the concentration of ALT in the blood causes a decrease in the water potential of the blood.

State precisely the name and location of the cells where a change in the water potential of the blood would be detected.

1M
(d)

Describe the homeostatic role of ADH when the water potential of the blood decreases.

5M

The rest of this paper

9 more questions
  • Q2Inheritance · Genetic Technology12M
  • Q3Selection and Evolution · Genetic Technology · Classification, Biodiversity and Conservation12M
  • Q4Genetic Technology10M
  • Q5Inheritance · Genetic Technology11M
  • Q6Homeostasis · Control and Coordination11M
  • Q7Energy and Respiration12M
  • Q8Classification, Biodiversity and Conservation8M
  • Q9Genetic Technology15M
  • Q10Photosynthesis15M
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