AQA GCSE Biology 8461: Homeostasis and response – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover topic 5, Homeostasis and response (sections 4.5.1–4.5.4), of the AQA GCSE Biology (8461) specification, for teaching from September 2016 and exams from 2018 onwards. The topic is examined on Paper 2, set at Foundation and Higher tier. Parts labelled (Higher tier only) test content the specification marks “(HT only)”; Foundation candidates can skip them.

Learn the content first in the study guide and the revision notes. The course hub is AQA GCSE Biology, and the printable checklist lists every statement.

Questions

1. Define homeostasis and name two internal conditions controlled in the human body. [3]

2. A person touches a hot pan and pulls their hand away. Describe the pathway of the reflex arc from the stimulus to the response. [4]

3. A student investigates the effect of loud music on reaction time. She uses a computer test five times in silence and five times with loud music.

Test	1	2	3	4	5
Silence (s)	0.28	0.26	0.30	0.27	0.29
Loud music (s)	0.36	0.33	0.39	0.34	0.38

(a) Calculate the mean reaction time for each condition. [2] (b) Calculate the percentage increase in mean reaction time with loud music. Give your answer to 3 significant figures. [2] (c) Give two variables the student should control. [2] (d) Suggest why she repeated each test five times. [1]

4.

(a) Describe how the eye focuses on a distant object. [3] (b) A person has myopia. Explain why they see distant objects as blurred and how spectacles correct this. [2]

5. A runner competes on a hot day.

(a) Name the part of the brain that monitors blood temperature. [1] (b) (Higher tier only) Explain how two responses in the skin lower the runner’s body temperature. [4]

6. Two people each have a glucose drink after fasting. Their blood glucose concentration is measured.

Time (min)	0	45	60	120
Person A (mmol/dm³)	5.0	9.5	8.6	5.0
Person B (mmol/dm³)	5.5	12.8	14.0	13.2

(a) Calculate the mean rate of fall in person A’s blood glucose between 45 and 120 minutes. [2] (b) Person B has Type 1 diabetes. Use the data to explain this. [2] (c) (Higher tier only) Explain how insulin and glucagon interact in a negative feedback cycle to keep blood glucose concentration within normal limits. [3]

7. In one day a person’s kidneys filter 150 dm³ of fluid and produce 1.2 dm³ of urine.

(a) Calculate the percentage of the filtered water that is reabsorbed. Give your answer to 1 decimal place. [2] (b) Explain why urine from a healthy person contains no glucose. [2] (c) (Higher tier only) On a hot day the person sweats heavily. Explain how ADH changes the volume of urine produced. [3]

8. Evaluate kidney dialysis and kidney transplant as treatments for kidney failure. [6]

9. (Higher tier only) Explain how FSH, oestrogen, LH and progesterone interact to control the menstrual cycle. [6]

10. (Higher tier only) A fertility clinic records the results of IVF treatment.

Age of woman	Treatment cycles	Live births
Under 35	350	126
Over 40	300	21

(a) Calculate the success rate for each age group as a percentage. [2] (b) Describe the main stages of IVF treatment. [4] (c) Give two drawbacks of IVF treatment for the mother. [2]

11. Newly germinated seedlings are placed in a box lit from one side. After three days the shoot lengths are 42 mm, 38 mm, 45 mm, 40 mm and 35 mm.

(a) Calculate the mean shoot length. [1] (b) Explain why the shoots bend towards the light. [3] (c) (Higher tier only) Give two ways growers use plant hormones other than auxin. [2]

12. (Higher tier only)

(a) Describe the effects of adrenaline on the body. [2] (b) Explain how negative feedback keeps the thyroxine level in the blood steady. [2]

Answers

1. Homeostasis is the regulation of internal conditions (of a cell or organism) [1]; to maintain optimum conditions for function, in response to internal and external changes [1]; any two of blood glucose concentration, body temperature, water levels [1] [3] Examiner insight: A definition that only says “keeping things constant” usually earns one mark at most; the second mark needs “optimum conditions” or “in response to changes”.

2. Receptor (in skin) detects the heat [1]; impulse travels along a sensory neurone to the spinal cord [1]; passes across synapses via a relay neurone to a motor neurone [1]; motor neurone carries impulse to the effector (muscle), which contracts [1] [4] Examiner insight: Each neurone must be named in the correct order; “a nerve sends a message to the brain” is too vague to score and the brain is not the coordinator here.

3. (a) Silence: 1.40 / 5 = 0.28 s [1]; loud music: 1.80 / 5 = 0.36 s [1] (b) (0.36 − 0.28) / 0.28 × 100 [1] = 28.6% [1] (c) Same person tested [1]; same hand used (or same test, same time of day, same volume of music) [1] (d) To identify anomalies and calculate a mean, so the result is more precise [1] Examiner insight: In (b) the method mark needs the original value, 0.28, as the denominator; dividing by 0.36 gives 22.2% and scores neither mark.

4. (a) Ciliary muscles relax [1]; suspensory ligaments are pulled tight [1]; lens is pulled thin and refracts light only slightly [1] (b) Light from distant objects is focused in front of the retina [1]; a concave (diverging) lens spreads the rays so they focus on the retina [1] Examiner insight: Reversing near and distant changes is a contradiction and scores zero for that step; learn the three-step chain as a fixed order.

5. (a) Thermoregulatory centre [1] (b) Blood vessels supplying skin capillaries dilate (vasodilation) [1]; more blood flows near the skin surface so more energy is transferred to the surroundings [1]; sweat glands produce more sweat [1]; sweat evaporates, transferring energy from the skin [1] Examiner insight: “Blood vessels move closer to the skin” is a common wrong statement and is not credited; the vessels dilate.

6. (a) (9.5 − 5.0) / (120 − 45) = 4.5 / 75 [1] = 0.06 mmol/dm³ per minute [1] (b) Person B’s glucose rises higher (14.0 compared with 9.5) [1]; and stays high at 120 minutes because little or no insulin is produced [1] (c) When glucose is high the pancreas releases insulin, so glucose moves into cells and is stored as glycogen [1]; if glucose falls too low the pancreas releases glucagon [1]; glucagon causes glycogen to be converted to glucose and released into the blood, so the level rises back to normal (negative feedback) [1] Examiner insight: Data questions need figures quoted from the table; “it is higher” without values often loses the comparison mark.

7. (a) (150 − 1.2) / 150 × 100 [1] = 99.2% [1] (b) Glucose is filtered out of the blood [1]; all of it is selectively reabsorbed back into the blood [1] (c) Blood becomes more concentrated, so the pituitary gland releases more ADH [1]; ADH makes the kidney tubules more permeable to water [1]; more water is reabsorbed into the blood, so a smaller volume of more concentrated urine is produced [1] Examiner insight: In (c), saying ADH “makes the kidney produce less water” without mentioning permeability or reabsorption misses the key mark.

8. Dialysis: available without waiting for a donor [1]; but sessions take several hours several times a week and diet must be controlled [1]; dialysis fluid removes urea but keeps glucose and useful ions, as it has the same concentrations as normal blood [1]. Transplant: patient is free of regular sessions and has a more normal life [1]; but needs a tissue-matched donor, and there is a shortage [1]; lifelong drugs are needed to prevent rejection, and the operation has risks [1] [6] Examiner insight: For an “evaluate” question the top marks need points on both treatments and a judgement or balance; describing only one method caps the response in the lower bands.

9. FSH is secreted by the pituitary and causes an egg to mature in the ovary [1]; FSH stimulates the ovary to produce oestrogen [1]; oestrogen causes the uterus lining to build up [1]; oestrogen inhibits FSH and stimulates the release of LH [1]; LH stimulates ovulation (release of the egg, around day 14) [1]; progesterone maintains the uterus lining and inhibits FSH and LH; when progesterone falls the lining breaks down [1] [6] Examiner insight: Extended answers are marked on a logical chain; a list of hormones with no links between them stays in the lowest level.

10. (a) Under 35: 126 / 350 × 100 = 36.0% [1]; over 40: 21 / 300 × 100 = 7.0% [1] (b) Woman is given FSH and LH to stimulate several eggs to mature [1]; eggs are collected [1]; eggs are fertilised by the father’s sperm in the laboratory and develop into embryos [1]; one or two embryos (tiny balls of cells) are inserted into the uterus [1] (c) It is emotionally and physically stressful [1]; multiple births risk the health of the mother (and babies) [1] Examiner insight: “Given hormones” without naming FSH and LH does not score the first marking point in (b).

11. (a) (42 + 38 + 45 + 40 + 35) / 5 = 40 mm [1] (b) Auxin collects on the shaded side of the shoot [1]; cells on the shaded side elongate (grow) faster [1]; so the shoot grows unevenly and bends towards the light (phototropism) [1] (c) Ethene to control fruit ripening during storage and transport [1]; gibberellins to end seed dormancy, promote flowering or increase fruit size [1] Examiner insight: Each mark in (b) needs the side named: “auxin collects on the shaded side” scores, but saying light “kills” cells or auxin gains no credit.

12. (a) Increases heart rate [1]; boosts delivery of oxygen and glucose to the brain and muscles, preparing the body for fight or flight [1] (b) When thyroxine falls below normal, the thyroid is stimulated to release more [1]; when it rises above normal, the stimulation is reduced, so the level returns to normal [1] Examiner insight: Negative feedback answers need both directions of change; describing only the rise earns one of the two marks.

Where marks are usually lost

• Naming “the brain” as the coordinator in a spinal reflex, or leaving out the synapse.
• Percentage change calculated using the new value as the denominator.
• Mean reaction times given without units.
• Swapping the ciliary muscle and ligament changes for near and distant objects.
• Writing “vessels move to the surface” instead of vasodilation.
• Confusing glucagon and glycogen, or placing glycogen storage in the blood.
• Describing ADH as reducing water reabsorption.
• Hormone chains in the menstrual cycle with no causal links.
• Saying IVF puts “eggs” into the uterus rather than embryos.
• Plant answers that name auxin but not the side of the shoot where it collects.

Next steps

• Recap with the revision notes.
• Reread any weak section in the study guide.
• Browse other topics on the AQA GCSE Biology hub.
• Track coverage with the printable checklist.
• Try all free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

AQA GCSE Biology (8461) specification, Version 1.0 (21 April 2016), for teaching from September 2016 and exams from 2018 onwards, AQA – section 4.5, Homeostasis and response.