6 exam-style questions with full mark schemes and model answers. Write your own answer and the AI examiner marks it against the mark scheme.
After a person eats a large, sugary meal, the concentration of glucose in their blood rises. A short time later it returns to its normal level. The body controls blood glucose concentration by negative feedback involving the pancreas, the hormone insulin, and the liver.
Explain how the body lowers a raised blood glucose concentration back to normal, and explain why this is described as negative feedback. (6 marks)
When a person touches a sharp pin, they pull their hand away very quickly without thinking. This is a reflex action, carried out by a reflex arc.
(a) Name the structures, in the correct order, through which the nerve impulse travels in this reflex arc, from the receptor in the skin to the effector. (3 marks)
(b) Explain one advantage of a reflex action being automatic (not involving conscious thought). (1 mark)
The eye is a sense organ that responds to light. The iris controls how much light enters the eye by changing the size of the pupil.
(a) Describe what happens to the iris muscles and the pupil when a person moves from a dimly lit room into bright sunlight. (2 marks)
(b) Explain why this response is important. (1 mark)
Humans keep their core body temperature close to 37 °C. This is controlled by a part of the brain.
(a) Name the part of the brain that monitors and controls body temperature. (1 mark)
(b) Describe two ways the body responds to reduce heat loss when a person becomes too cold. (2 marks)
The kidneys help control the water content of the blood. On a hot day, a person sweats a lot and does not drink much water, so their blood becomes too concentrated (it contains too little water).
Describe how the body responds to make the urine more concentrated, so that less water is lost from the body. Refer to the hormone ADH. (2 marks)
Plants respond to light. A shoot grown on a sunny windowsill grows towards the light. This response is called phototropism and is controlled by a plant hormone.
Name the plant hormone responsible for this growth response in shoots. (1 mark)