OCR GCSE Biology A: Homeostasis, temperature control and blood glucose regulation (J247) – 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 statements B3.3a to B3.3e of module B3.3 in OCR GCSE (9-1) Gateway Science Biology A (J247), specification Version 4.0 (August 2026), for first assessment in 2018. Questions 8 and 9 draw on B3.3d (glucagon), which is in bold in the specification and so Higher Tier only; they are labelled. All other questions suit both tiers. Learn the content from the study guide or the revision notes. Course pages: OCR GCSE Biology hub | checklist | free 10-minute diagnostics.

Questions

1. Explain why core body temperature must be kept close to 37 °C. [3]

2. Describe how the body responds when the external temperature falls. [4]

3. A volunteer rests in rooms at different air temperatures. Blood flow through the skin of the forearm is measured. Core temperature stays at 37.0 °C throughout.

Air temperature (°C)	15	25	35
Skin blood flow (arbitrary units)	22	60	150

(a) Calculate the percentage increase in skin blood flow from 25 °C to 35 °C. [2] (b) Explain the change in skin blood flow between 15 °C and 35 °C. [2]

4. On a very humid day, a person finds it hard to stay cool even though they are sweating heavily. Explain why. [4]

5. A student writes: “In hot weather, blood vessels move closer to the skin so more heat can escape.” Correct the statement. [3]

6. Explain how the body brings blood glucose concentration back to normal after a meal rich in carbohydrate. [5]

7. A healthy person eats a meal at time 0. Blood glucose and insulin are measured every 20 minutes.

Time (min)	0	20	40	60	80	100
Glucose (mmol/dm³)	4.9	6.8	7.9	6.2	5.3	5.0
Insulin (arbitrary units)	8	24	44	56	34	14

(a) Calculate the percentage increase in blood glucose from time 0 to its peak. [2] (b) Calculate the mean rate of fall of blood glucose from 40 to 80 minutes, in mmol/dm³ per minute. [2] (c) Explain why the insulin peak occurs after the glucose peak. [2]

8. (Higher Tier only) A runner has been running for several hours and their blood glucose begins to fall. Explain how glucagon and insulin bring about the return towards normal. [5]

9. (Higher Tier only) A person’s blood glucose falls from 5.0 to 4.0 mmol/dm³ after 6 hours without food.

(a) Calculate the percentage decrease. [2] (b) Explain why the fall is not larger, referring to glucagon. [3]

10. (a) Compare the causes of type 1 and type 2 diabetes. [4] (b) Explain why insulin for type 1 diabetes is injected instead of being taken as a tablet. [2]

11. Three adults fast overnight, then drink a glucose solution. Their blood glucose (mmol/dm³) is measured.

Time after drink (h)	0	1	2	3
Person X	4.6	7.2	5.0	4.6
Person Y	11.2	18.5	20.1	19.8
Person Z	7.8	13.9	15.1	12.4

(a) State which person has normal glucose regulation, using data to justify your answer. [2] (b) Calculate the percentage increase in Y’s glucose from time 0 to its peak. [2] (c) Person Z has type 2 diabetes and person Y has type 1. Use the data to support these diagnoses. [2] (d) Suggest how Z’s condition may be treated at first. [2]

12. A survey records how many adults in each body mass index (BMI) group have type 2 diabetes.

BMI group	Adults surveyed	Adults with type 2 diabetes
Under 25	2000	24
25 to 29.9	1600	48
30 or over	900	72

(a) Calculate the percentage of adults with type 2 diabetes in each group. [3] (b) Describe the relationship shown, using the data, and state how many times greater the percentage is in the highest BMI group than in the lowest. [2] (c) Explain why the survey does not prove that a high BMI causes type 2 diabetes. [2] (d) Explain how type 2 diabetes affects blood glucose and suggest one lifestyle change that lowers the risk. [2]

Answers

1. Metabolic reactions are controlled by enzymes [1]. If the temperature is too high, the enzyme’s shape (active site) changes, it denatures and the reaction slows or stops [1]. If the temperature is too low, there are fewer collisions between enzyme and substrate, so reactions are too slow [1]. [3] Examiner insight: The idea is that enzymes work best near an optimum. An answer saying only “the body would be too hot or cold” gives no biology to credit.

2. Temperature receptors in the skin detect the fall and the brain responds [1]. Shivering: skeletal muscles contract rapidly and respiration releases heat [1]. Vasoconstriction: the arterioles to the skin narrow, so the surface capillaries receive less blood [1]. Less heat is transferred to the surroundings and less sweat is produced [1]. [4] Examiner insight: “Describe” means state what happens. Name each response and say what changes.

3. (a) Increase = 150 − 60 = 90 [1]. 90 ÷ 60 × 100 = 150% [1]. (b) Skin blood flow rises as air temperature rises because of vasodilation: the arterioles widen, sending extra blood close to the surface [1]. More heat is transferred to the surroundings, which keeps core temperature constant at 37.0 °C [1]. [4] Examiner insight: Divide by the starting value, 60. In (b), link the change in flow to the effect on core temperature.

4. Sweat cools the body when it evaporates, which transfers energy from the skin to the surroundings [1]. In humid air the air already holds a lot of water vapour [1]. So sweat evaporates more slowly [1]. Less energy is transferred from the skin, so cooling is less effective and body temperature may rise above 37 °C [1]. [4] Examiner insight: “Sweating cools you” alone is only the starting point. Explain why evaporation is slowed.

5. Blood vessels do not move [1]. The arterioles supplying the skin capillaries widen (vasodilation) [1]. More blood flows near the surface, so more heat is transferred to the surroundings [1]. [3] Examiner insight: A “correct the statement” question needs the right idea stated, not just the word “wrong”. Use the term vasodilation and say what widens.

6. The pancreas detects the rise in blood glucose and secretes insulin [1]. Insulin is carried in the blood [1]. Target cells, mainly in the liver and muscles, take up glucose from the blood [1]. The liver converts glucose to glycogen for storage [1]. As blood glucose falls back to normal, less insulin is secreted (negative feedback) [1]. [5] Examiner insight: Name the gland, the hormone, the target and the effect. “Insulin lowers sugar” states a result without explaining it.

7. (a) Rise = 7.9 − 4.9 = 3.0 [1]. 3.0 ÷ 4.9 × 100 = 61% [1]. (b) Fall = 7.9 − 5.3 = 2.6 [1]. 2.6 ÷ 40 = 0.065 mmol/dm³ per minute [1]. (c) The pancreas secretes insulin in response to the rise in glucose, so insulin follows glucose [1]. Time is needed for release and transport in the blood, and insulin stays high while glucose is still above normal [1]. [6] Examiner insight: A rate needs units that include time.

8. (Higher Tier only) The pancreas detects the low glucose concentration and secretes glucagon [1]. Glucagon travels in the blood to the liver [1]. The liver converts stored glycogen to glucose [1] and releases it into the blood, so glucose concentration rises [1]. Insulin secretion falls, so cells take up less glucose, and as glucose returns to normal glucagon release falls (negative feedback) [1]. [5] Examiner insight: Say which hormone is released at low glucose and what the liver does, and avoid confusing glucagon with glycogen.

9. (a) (Higher Tier only) Fall = 1.0 [1]. 1.0 ÷ 5.0 × 100 = 20% [1]. (b) Falling glucose stimulates the pancreas to release glucagon [1]. Glucagon makes the liver convert glycogen to glucose [1] and release it into the blood, which limits the fall [1]. [5] Examiner insight: “Why is the fall not larger” needs a mechanism: link low glucose to the hormone, the organ and the glycogen store.

10. (a) In type 1, the pancreas does not make enough insulin (usually because the immune system destroys the insulin-producing cells) [1]. In type 2, body cells do not respond properly to insulin [1]. Type 1 is not caused by diet [1]. Type 2 is linked to obesity, inactivity, poor diet, age or family history [1]. (b) Insulin is a protein [1]. A tablet would be digested in the gut so it would not reach the blood intact [1]. [6] Examiner insight: A comparison needs both sides in each point, so use “whereas” and complete the contrast.

11. (a) X [1]: glucose peaks at 7.2 at 1 hour and returns to 4.6 by 3 hours, the same as the starting value [1]. (b) Rise = 20.1 − 11.2 = 8.9 [1]. 8.9 ÷ 11.2 × 100 = 79% [1]. (c) Y starts high and stays at 19.8 at 3 hours, so almost none is removed, as expected if little insulin is made (type 1) [1]. Z falls from 15.1 to 12.4 between 2 and 3 hours, so some glucose is removed, but slowly, as expected if cells respond poorly to insulin (type 2) [1]. (d) Lifestyle change: a healthier diet, regular exercise or weight loss [1]. If that is not enough, medicines (such as metformin) can be used [1]. [8] Examiner insight: Support each claim with a quoted value and a time.

12. (a) 24 ÷ 2000 × 100 = 1.2% [1]; 48 ÷ 1600 × 100 = 3.0% [1]; 72 ÷ 900 × 100 = 8.0% [1]. (b) The higher the BMI group, the higher the percentage with type 2 diabetes (a positive correlation) [1]. 8.0 ÷ 1.2 = 6.7 times greater [1]. (c) A correlation shows an association only [1]. Other factors, such as diet, inactivity, age or family history, may differ between the groups [1]. (d) In type 2, cells respond poorly to insulin, so blood glucose stays too high [1]. Lifestyle change: regular exercise, a healthier diet or weight loss [1]. [9] Examiner insight: Convert counts to percentages before comparing groups of different sizes.

Where marks are usually lost

• Writing that blood vessels move towards or away from the skin instead of arterioles widening or narrowing.
• Saying sweating cools the body without saying that evaporation transfers energy.
• Describing a response without its effect, such as vasoconstriction with no mention of heat transfer.
• Saying insulin “breaks down” or “removes” glucose with no mention of cells taking it up or the liver storing glycogen.
• Mixing up glycogen and glucagon.
• Leaving out the pancreas, or leaving out that hormones travel in the blood.
• Giving type 2 diabetes as “no insulin” rather than cells that respond poorly.
• Calculating percentage change by dividing by the final value.
• Forgetting units on a rate, or quoting data with no time.
• Claiming a correlation proves a cause.

Next steps

• Re-read the revision notes and the study guide.
• Course pages: OCR GCSE Biology hub and checklist.
• Find your weak spots with the free 10-minute diagnostics.
• Want a teacher to go through your answers? Book a free trial class.

Official syllabus

OCR GCSE (9-1) Gateway Science Biology A (J247), specification Version 4.0 (August 2026), for first assessment in 2018, published by OCR. Module B3.3, statements B3.3a to B3.3e.