Unsorted Past Paper Questions

Question 1

Some people cannot digest lactose when they are adult. They could digest lactose
when they were children.
Use your knowledge of water potential to explain why these adults get diarrhoea when they drink milk

Answer 1

Lower water potential in lumen/intestine/gut

Water enters lumen/leaves (body) cells/ by osmosis

Question 2

Describe the path by which oxygen goes from an alveolus to the blood.

Answer 2

Through alveolar epithelium

Through capillary epithelium/endothelium

Question 3

In healthy lungs, a gradient is maintained between the concentration of oxygen in the
alveoli and the concentration of oxygen in the lung capillaries.
Describe how ventilation helps to maintain this difference in oxygen
concentration.

Answer 3

(In alveolus)
Brings in air containing a high(er) oxygen concentration
Removes air with a low(er) oxygen concentration

Question 4

Ventilation helps maintain a difference in oxygen concentration. Give one other way.

Answer 4

Circulation of blood

Question 5

Explain how the mitochondria help the cell absorb the products of digestion

Answer 5

(Site of aerobic) respiration/ATP production/energy release

Active transport/transport against the concentration gradient