Edexcel GCSE Combined Science: Biology: Plant and Animal Coordination and Control
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 meal high in sugar, the concentration of glucose in their blood rises. Within a couple of hours it returns to normal. The pancreas, the hormone insulin and the liver are all involved.
Explain how the body controls the blood glucose concentration and returns it to normal after a sugary meal. In your answer you should refer to the pancreas, insulin, the liver and glycogen. (6 marks)
In a core practical, a student investigated phototropism — the growth of plant shoots towards light. Cress seedlings were grown for 3 days with light coming from one side only. The student measured the angle each seedling bent towards the light. The mean results are shown below.
| Light condition | Mean angle of bending towards the light / degrees |
|---|---|
| Light from the right-hand side | 38 |
| Light from above (all around) | 0 |
| Tip removed, light from the right | 2 |
(a) Explain why the seedlings with light from one side bent towards the light. Refer to the plant hormone auxin. (3 marks)
(b) Suggest why the seedlings whose tip was removed bent by only 2°. (1 mark)
When a person becomes too hot, the body responds to cool down. This control of body temperature is called thermoregulation.
(a) When a person is too hot, they sweat more. Explain how sweating helps to cool the body down. (2 marks)
(b) Name the type of coordination — nervous or hormonal — that mainly controls the body's temperature responses such as sweating. (1 mark)
(Higher tier) The hormone thyroxine controls the body's metabolic rate. Its level in the blood is kept fairly constant by negative feedback.
Explain how negative feedback keeps the level of thyroxine in the blood roughly constant when the thyroxine level rises above normal. (3 marks)
During the menstrual cycle, the hormone oestrogen is involved in the build-up of the uterus lining. Some contraceptives contain hormones.
Explain how a contraceptive pill that contains hormones can prevent pregnancy. (2 marks)
Hormones are chemical messengers that are transported around the body.
Name the fluid in which hormones are transported around the body. (1 mark)