OxfordAQA International GCSE Biology: Homeostasis, temperature control and blood glucose (9201) – 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 practice questions are aligned to the OxfordAQA International GCSE Biology (9201) specification, Version 5.2, for exams from May/June 2018 onwards. They cover sections 3.4.2 (Homeostasis), 3.4.4 (Temperature control) and 3.4.5 (Control of blood glucose). The qualification is untiered. Revise with the study guide and the revision notes. Course pages: OxfordAQA IGCSE Biology hub and printable checklist.

Questions

1. State where in the body you would find receptors that are sensitive to each of the following. (a) The concentration of glucose in the blood. [1] (b) The temperature of blood. [1] (c) Touch and pressure. [1]

2. The body has automatic control systems. (a) Name two internal conditions that are controlled, other than temperature. [2] (b) Name two coordination centres. [2]

3. On a hot day a cyclist’s core temperature begins to rise. Explain how the body responds. [5]

4. A volunteer’s temperatures were measured in cold air and in warm air.

Air temperature	Core temperature (°C)	Finger skin temperature (°C)
5 °C	37.0	12.0
30 °C	37.1	31.0

(a) Calculate the difference between core and finger temperature at each air temperature. [2] (b) Explain, with reference to blood vessels, why the finger was much cooler at 5 °C. [3] (c) At 5 °C the volunteer began to shiver. Explain how shivering helps to keep core temperature constant. [2]

5. A builder works for 6 hours on a hot day and sweats at a mean rate of 1.2 dm³ per hour. She drinks 3.9 dm³ of water during the shift. (a) Calculate how much more sweat she lost than water she drank. [2] (b) Explain how sweating cools the body. [2] (c) Explain why she needs to take in more fluid than on a cold day. [1]

6. A student drinks a large glass of sweetened juice. Explain how the body brings blood glucose back down. [5]

7. A person goes for many hours without food. Explain how the body stops blood glucose from falling too far. [4]

8. A volunteer did not eat for 8 hours. Blood glucose and the concentration of hormone P were measured. Hormone P is made in the pancreas.

Time (h)	0	2	4	6	8
Blood glucose (mmol/dm³)	5.4	4.8	4.2	4.6	5.0
Hormone P (arbitrary units)	6	14	30	22	12

(a) Calculate the percentage fall in blood glucose from 0 to 4 hours. [2] (b) Hormone P is glucagon. Use the data to support this. [2] (c) Explain how glucagon makes blood glucose rise. [2] (d) Calculate the mean rate of increase in blood glucose from 4 to 8 hours. [2]

9. A trial compared two ways of treating adults with Type 2 diabetes for 12 weeks. Mean blood glucose is given.

Treatment	Before (mmol/dm³)	After (mmol/dm³)
Diet and exercise only	9.8	9.1
Diet, exercise and a drug that helps cells respond to insulin	9.9	7.4

(a) Calculate the percentage fall in each group. [3] (b) What conclusion can be drawn about the drug? [2] (c) Explain how this kind of drug helps in Type 2 diabetes. [1] (d) Suggest one factor that should be the same in both groups. [1]

10. Compare Type 1 and Type 2 diabetes. Include the cause of each and how each may be controlled. [6]

11. A marathon runner runs for 3 hours on a hot day. Explain how her body maintains her core temperature and her blood glucose concentration. [9]

Answers

1. (a) The pancreas. [1] (b) The brain. [1] (c) The skin. [1] Examiner insight: A named organ is needed for each part. “Blood” is not a place that holds receptors, so an answer of that kind is unlikely to gain credit.

2. (a) Any two of: water content of the body [1], ion content of the body [1], blood glucose levels. Two different conditions are needed. (b) Any two of: brain [1], spinal cord [1], pancreas. Examiner insight: “Temperature” is excluded by the question, so repeating it cannot gain credit. Read the exclusion in the stem before listing.

3. Receptors in the brain detect the temperature of the blood, and skin receptors send impulses to the thermoregulatory centre. [1] Blood vessels supplying the skin capillaries dilate. [1] More blood flows through the skin capillaries, so more energy is transferred from the skin to the environment. [1] Sweat glands release more sweat. [1] The sweat cools the body as it evaporates. [1] Examiner insight: Answers tend to gain credit when they say what the blood vessels do and what that does to energy transfer. “Vessels move to the skin” gives a wrong picture of vasodilation.

4. (a) At 5 °C: 37.0 − 12.0 = 25.0 °C. [1] At 30 °C: 37.1 − 31.0 = 6.1 °C. [1] (b) The blood vessels supplying the skin capillaries constrict. [1] Less blood flows through the capillaries in the finger. [1] Less energy is transferred from the blood to the surroundings, so the skin stays cooler while the core stays near 37 °C. [1] (c) Muscle contraction needs respiration. [1] Respiration transfers some energy that warms the body. [1] Examiner insight: Show the subtraction and include the unit. In part (b), a chain from vessel diameter to blood flow to energy transfer gains credit more reliably than “to keep heat in”.

5. (a) Sweat lost = 1.2 × 6 = 7.2 dm³. [1] Difference = 7.2 − 3.9 = 3.3 dm³. [1] (b) Sweat is made by sweat glands and spreads over the skin surface. [1] Sweat cools the body as it evaporates. [1] (c) More water is lost when it is hot, so more fluid has to be taken in through drink or food to balance the loss. [1] Examiner insight: Quoting the intermediate value of 7.2 dm³ makes the method visible. In part (b), the word “evaporates” carries the point.

6. The pancreas detects the high glucose concentration. [1] The pancreas produces insulin. [1] Insulin allows glucose to move from the blood into the cells. [1] Much of the glucose is stored as glycogen in the liver and muscles. [1] When these stores are full, excess glucose is stored as lipid. [1] Examiner insight: Say where the glucose goes (into cells) and what it becomes (glycogen). “Insulin gets rid of sugar” is too vague to show the mechanism.

7. The pancreas detects that blood glucose is falling. [1] The pancreas produces glucagon. [1] Stored glycogen is turned back into glucose. [1] This glucose enters the blood, so blood glucose rises. [1] Examiner insight: Naming the stored substance (glycogen) and the product (glucose) is what separates a complete answer from “glucagon raises blood sugar”.

8. (a) Fall = 5.4 − 4.2 = 1.2. [1] 1.2 ÷ 5.4 × 100 = 22%. [1] (b) Hormone P rises as blood glucose falls. [1] It peaks (30 units) at 4 hours, when glucose is lowest (4.2), and then glucose rises. [1] (c) Glucagon makes stored glycogen change back into glucose. [1] The glucose passes into the blood. [1] (d) Rise = 5.0 − 4.2 = 0.8 mmol/dm³ in 4 hours. [1] Rate = 0.8 ÷ 4 = 0.20 mmol/dm³ per hour. [1] Examiner insight: Quote values from the table when supporting a claim, and divide by the starting value for a percentage. A rate needs its unit, including “per hour”.

9. (a) Percentage change = fall ÷ starting value × 100. [1] Diet and exercise only: 0.7 ÷ 9.8 × 100 = 7.1%. [1] With the drug: 2.5 ÷ 9.9 × 100 = 25%. [1] (b) The group that also took the drug had a larger fall (25% against 7.1%). [1] This suggests the drug lowers blood glucose further than diet and exercise alone. [1] (c) It helps the cells to respond to insulin, so more glucose moves from the blood into cells. [1] (d) Any one of: the diet, the amount of exercise, the age of the patients, body mass, the starting blood glucose. [1] Examiner insight: Support a conclusion with both figures and keep the claim to what the data show. Saying the drug “cures” diabetes goes beyond a 12-week fall in glucose.

10. Type 1: the pancreas does not produce enough insulin. [1] Type 2: the body does not respond to its own insulin. [1] Obesity is a significant factor in the development of Type 2 diabetes. [1] Type 1 may be controlled by careful diet, exercise and injecting insulin. [1] Type 2 may be controlled by careful diet, exercise and drugs that help the cells to respond to insulin. [1] Both can lead to blood glucose being too high. [1] Examiner insight: A comparison needs both types in each point. Writing two separate lists without a link between them tends to leave the comparison implied rather than stated.

11. Temperature: Receptors detect the rise in blood temperature and skin temperature, and send information to the thermoregulatory centre. [1] Skin blood vessels dilate, so more energy is transferred to the environment. [1] Sweat glands release more sweat, which cools the body as it evaporates. [1] She must drink to replace the water lost. [1] Glucose: Her muscles use glucose in respiration, so blood glucose falls. [1] The pancreas detects the fall and produces glucagon. [1] Glucagon makes stored glycogen change back into glucose, which enters the blood. [1] After the run, eating raises blood glucose, so the pancreas produces insulin. [1] Insulin allows glucose to move from the blood into cells, where it can be stored as glycogen. [1] Examiner insight: A longer answer is easier to follow when it is split into temperature and glucose, with each response linked to what it changes. Listing responses without the effect leaves points unproven.

Where marks are usually lost

• Naming “blood” or “the body” instead of an organ in a question about where receptors are found.
• Repeating a condition the question has already excluded.
• Saying that vessels move, rather than that they dilate or constrict.
• Saying sweat cools you without mentioning evaporation.
• Writing “insulin lowers blood sugar” with no mention of glucose moving into cells.
• Writing “glucagon raises blood sugar” with no mention of stored glycogen changing back into glucose.
• Describing Type 2 diabetes as a lack of insulin.
• Dividing by the final value when calculating a percentage change.
• Leaving out units, or the “per hour”, on a rate.

Next steps

• Re-read the study guide for any question you lost marks on.
• Learn the revision notes.
• Go to the OxfordAQA IGCSE Biology hub and tick off topics on the checklist.
• Find gaps with the free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

The OxfordAQA International GCSE Biology (9201) specification, Version 5.2, for exams May/June 2018 onwards, published by OxfordAQA.