AQA GCSE Biology · 4.5

Homeostasis and response

50 exam-style questions with answers for 4.5 Homeostasis and response in AQA GCSE Biology (spec 8461). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, or read every question and answer below. Not official AQA material.

All 50 questions and answers

Question 1 · Spec 4.5.1 · Homeostasis
Define homeostasis. [1 mark]
Answer:
The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes.
Question 2 · Spec 4.5.1 · Homeostasis
State three conditions controlled by homeostasis in humans. [3 marks]
Answer:
Blood glucose concentration (1); body temperature (1); water levels (1).
Question 3 · Spec 4.5.1 · Control systems
Name the three parts of an automatic control system. [3 marks]
Answer:
Receptors detect stimuli (1); coordination centres (brain, spinal cord, pancreas) process information (1); effectors (muscles or glands) bring about responses (1).
Question 4 · Spec 4.5.2.1 · Nervous system
Describe the pathway of a response in the nervous system. [2 marks]
Answer:
Stimulus → receptor → coordinator (1); → effector → response (1).
Question 5 · Spec 4.5.2.1 · Reflexes
Describe a reflex arc. [3 marks]
Answer:
A receptor detects a stimulus and sends an impulse along a sensory neurone (1); a relay neurone in the spinal cord passes it on (1); a motor neurone carries the impulse to an effector, such as a muscle (1).
Question 6 · Spec 4.5.2.1 · Synapses
How is an impulse passed across a synapse? [2 marks]
Answer:
A chemical (neurotransmitter) is released (1); it diffuses across the gap and triggers an impulse in the next neurone (1).
Question 7 · Spec 4.5.2.1 · Required practical 7
Describe how to measure reaction time using a ruler drop test. [2 marks]
Answer:
One person drops a ruler between the other person's finger and thumb without warning (1); record the distance it falls before being caught and repeat to calculate a mean (1).
Question 8 · Spec 4.5.2.1 · Required practical 7
Name two control variables in a reaction time investigation. [2 marks]
Answer:
Any two from: same hand (1); same starting position of the ruler (1); same person dropping the ruler (1); no distractions (1).
Question 9 · Spec 4.5.2.2 · The brain
State the function of the cerebral cortex. [1 mark]
Answer:
It controls consciousness, intelligence, memory and language.
Question 10 · Spec 4.5.2.2 · The brain
State the function of the cerebellum. [1 mark]
Answer:
It coordinates muscle activity and balance.
Question 11 · Spec 4.5.2.2 · The brain
State the function of the medulla. [1 mark]
Answer:
It controls unconscious activities such as heart rate and breathing.
Question 12 · Spec 4.5.2.2 · The brain · Higher only
State two methods neuroscientists use to map brain function. [2 marks]
Answer:
Any two from: studying patients with brain damage (1); electrically stimulating parts of the brain (1); MRI scanning (1).
Question 13 · Spec 4.5.2.2 · The brain · Higher only
Why is treating brain damage difficult? [2 marks]
Answer:
The brain is complex and delicate (1); treatment may damage other areas, and some areas cannot be reached easily (1).
Question 14 · Spec 4.5.2.3 · The eye
State the function of the retina. [1 mark]
Answer:
It contains light-sensitive receptor cells.
Question 15 · Spec 4.5.2.3 · The eye
State the function of the iris. [1 mark]
Answer:
It controls the size of the pupil and so the amount of light entering the eye.
Question 16 · Spec 4.5.2.3 · The eye
Describe how the eye responds to bright light. [2 marks]
Answer:
The circular muscles of the iris contract and the radial muscles relax (1); so the pupil gets smaller, letting in less light (1).
Question 17 · Spec 4.5.2.3 · Accommodation
Describe how the eye focuses on a near object. [3 marks]
Answer:
The ciliary muscles contract (1); the suspensory ligaments loosen (1); the lens becomes thicker and refracts light more strongly (1).
Question 18 · Spec 4.5.2.3 · Eye defects
What is myopia and how is it treated? [2 marks]
Answer:
Short-sightedness: light focuses in front of the retina (1); treated with concave lenses (1).
Question 19 · Spec 4.5.2.3 · Eye defects
State two new technologies for treating eye defects. [2 marks]
Answer:
Any two from: hard and soft contact lenses (1); laser surgery to change the shape of the cornea (1); replacement lens (1).
Question 20 · Spec 4.5.2.4 · Body temperature
Where is body temperature monitored? [1 mark]
Answer:
The thermoregulatory centre in the brain, which has receptors sensitive to blood temperature.
Question 21 · Spec 4.5.2.4 · Body temperature · Higher only
Explain how the body cools down when too hot. [3 marks]
Answer:
Blood vessels supplying skin capillaries dilate (vasodilation), so more heat is lost from the skin by radiation (1); sweat glands release sweat (1); sweat evaporates, transferring heat from the skin (1).
Question 22 · Spec 4.5.2.4 · Body temperature · Higher only
Explain how shivering helps when the body is too cold. [1 mark]
Answer:
Muscles contract rapidly, which needs respiration, and this releases energy as heat.
Question 23 · Spec 4.5.3.1 · Endocrine system
Compare the effects of hormones and nerves. [2 marks]
Answer:
Hormones are carried in the blood and their effects are slower but act for longer (1); nerves are fast, short-lasting and act on a precise area (1).
Question 24 · Spec 4.5.3.1 · Endocrine system
Why is the pituitary gland called the 'master gland'? [1 mark]
Answer:
It secretes several hormones that act on other glands, stimulating them to release hormones.
Question 25 · Spec 4.5.3.2 · Blood glucose
Explain how blood glucose concentration is lowered. [2 marks]
Answer:
The pancreas releases insulin into the blood (1); which causes glucose to move into cells, and liver and muscle cells convert excess glucose to glycogen (1).
Question 26 · Spec 4.5.3.2 · Diabetes
Compare the causes of type 1 and type 2 diabetes. [2 marks]
Answer:
Type 1: the pancreas produces too little insulin (1); type 2: body cells no longer respond to insulin (1).
Question 27 · Spec 4.5.3.2 · Diabetes
How are type 1 and type 2 diabetes treated? [2 marks]
Answer:
Type 1 with insulin injections (1); type 2 with a carbohydrate-controlled diet and exercise (1).
Question 28 · Spec 4.5.3.2 · Blood glucose · Higher only
What happens if blood glucose concentration is too low? [2 marks]
Answer:
The pancreas releases glucagon (1); which causes glycogen to be converted into glucose and released into the blood (1).
Question 29 · Spec 4.5.3.3 · Water balance
State two ways water leaves the body. [2 marks]
Answer:
Any two from: from the lungs when we breathe out (1); from the skin in sweat (1); from the body in urine (1).
Question 30 · Spec 4.5.3.3 · Kidney
Describe how the kidney produces urine. [2 marks]
Answer:
Blood is filtered (1); then all the glucose, some ions and the water needed are selectively reabsorbed (1).
Question 31 · Spec 4.5.3.3 · Kidney · Higher only
Explain how urea is formed. [2 marks]
Answer:
Excess amino acids are deaminated in the liver to form ammonia (1); ammonia is toxic, so it is converted to urea for safe excretion (1).
Question 32 · Spec 4.5.3.3 · ADH · Higher only
Explain how ADH controls water levels. [3 marks]
Answer:
ADH is released by the pituitary gland when the blood is too concentrated (1); it makes the kidney tubules more permeable (1); so more water is reabsorbed into the blood (1).
Question 33 · Spec 4.5.3.3 · Kidney failure
State one advantage and one disadvantage of a kidney transplant compared to dialysis. [2 marks]
Answer:
Advantage: no need for long, regular dialysis sessions and a more normal diet (1). Disadvantage: risk of rejection, so lifelong immunosuppressant drugs are needed (1).
Question 34 · Spec 4.5.3.3 · Kidney failure
How does dialysis work? [2 marks]
Answer:
The patient's blood flows past a partially permeable membrane surrounded by dialysis fluid (1); urea diffuses out, while glucose and useful ions stay because the fluid has the same concentration as normal blood (1).
Question 35 · Spec 4.5.3.4 · Reproductive hormones
Name the main female and male reproductive hormones. [2 marks]
Answer:
Oestrogen, produced in the ovaries (1); testosterone, produced in the testes (1).
Question 36 · Spec 4.5.3.4 · Menstrual cycle
State the roles of FSH and LH. [2 marks]
Answer:
FSH causes an egg to mature in the ovary (1); LH stimulates the release of the egg (ovulation) (1).
Question 37 · Spec 4.5.3.4 · Menstrual cycle · Higher only
Explain how oestrogen and progesterone interact in the menstrual cycle. [2 marks]
Answer:
Oestrogen causes the uterus lining to thicken and inhibits FSH while stimulating LH release (1); progesterone maintains the uterus lining and inhibits FSH and LH (1).
Question 38 · Spec 4.5.3.5 · Contraception
Explain how the combined pill works. [2 marks]
Answer:
It contains oestrogen and progesterone (1); which inhibit FSH so no eggs mature (1).
Question 39 · Spec 4.5.3.5 · Contraception
State two non-hormonal methods of contraception. [2 marks]
Answer:
Any two from: condoms or diaphragms (1); intrauterine device (non-hormonal copper coil) (1); spermicides (1); abstaining around ovulation (1); surgical sterilisation (1).
Question 40 · Spec 4.5.3.6 · Infertility · Higher only
How is IVF carried out? [3 marks]
Answer:
The mother is given FSH and LH to stimulate several eggs to mature (1); eggs are collected and fertilised by sperm in the lab (1); embryos are inserted into the uterus (1).
Question 41 · Spec 4.5.3.6 · Infertility · Higher only
State two disadvantages of IVF. [2 marks]
Answer:
Any two from: it is emotionally and physically stressful (1); success rates are low (1); multiple births are a risk to mother and babies (1).
Question 42 · Spec 4.5.3.7 · Negative feedback · Higher only
Explain how thyroxine levels are controlled by negative feedback. [2 marks]
Answer:
When thyroxine levels fall, the pituitary releases TSH, stimulating the thyroid to make more (1); when levels rise, TSH release is reduced (1).
Question 43 · Spec 4.5.3.7 · Adrenaline · Higher only
Explain the effects of adrenaline. [2 marks]
Answer:
It increases heart rate (1); boosting delivery of oxygen and glucose to the brain and muscles for 'fight or flight' (1).
Question 44 · Spec 4.5.4.1 · Plant hormones
What is phototropism and what causes it? [2 marks]
Answer:
The growth of a shoot towards light (1); caused by an unequal distribution of auxin, which builds up on the shaded side (1).
Question 45 · Spec 4.5.4.1 · Plant hormones
Explain gravitropism in roots. [2 marks]
Answer:
Auxin collects on the lower side of the root (1); in roots, auxin inhibits growth, so the root bends downwards (1).
Question 46 · Spec 4.5.4.1 · Required practical 8
Describe how to investigate the effect of light on seedling growth. [2 marks]
Answer:
Grow cress seedlings with light from one side and a control in all-round light or dark (1); measure the length and direction of growth after several days (1).
Question 47 · Spec 4.5.4.1 · Plant hormones · Higher only
State the roles of gibberellins and ethene. [2 marks]
Answer:
Gibberellins initiate seed germination (1); ethene controls cell division and fruit ripening (1).
Question 48 · Spec 4.5.4.2 · Use of plant hormones · Higher only
State two uses of auxins. [2 marks]
Answer:
Any two from: weed killers (1); rooting powders (1); promoting growth in tissue culture (1).
Question 49 · Spec 4.5.4.2 · Use of plant hormones · Higher only
State two uses of gibberellins. [2 marks]
Answer:
Any two from: ending seed dormancy (1); promoting flowering (1); increasing fruit size (1).
Question 50 · Spec 4.5.4.2 · Use of plant hormones · Higher only
How is ethene used in the food industry? [1 mark]
Answer:
To control the ripening of fruit during storage and transport.

← 4.4 Bioenergetics 4.6 Inheritance, variation and evolution →

Homeostasis and response

All 50 questions and answers

More AQA GCSE Biology topics

Cookies on Knowledge Noodles

Cookie settings