AS & A Level Biology 9700 · Topic 14

Homeostasis: past paper questions

82 real questionsasked in 7 of the last 10 exam series2019–2025usually: Describe, Explain, Name, State, Suggest

Real questions on homeostasis

The newest 20 of 62 written questions, plus 20 multiple-choice. Open one to see it on the real paper.

9700/43 · May/June 2025 · Q10a[3]
Define the term ecosystem.
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9700/42 · February/March 2025 · Q6a(ii)[1]
State the type of homeostatic control mechanism operating in Fig. 6.1.
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9700/42 · February/March 2025 · Q6b[7]
When the blood glucose concentration decreases below the set point, a hormone is released from the pancreas. Describe how the release of this hormone leads to the blood glucose concentration returning to the set point.
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9700/41 · October/November 2024 · Q2a[3]
Explain why it is important for plants to open and close their stomata in a daily rhythm.
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9700/41 · October/November 2024 · Q2b[6]
Fig. 2.1 shows the results of an experiment to monitor this rhythm over three days and nights for the plant Arabidopsis thaliana. The percentage of open stomata is shown. Each day consisted of 14 hours of light (white bar) and each night consisted of 10 hours of darkness (black bar). 100 Key day night open stomata 50 /...
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9700/43 · October/November 2024 · Q2a[3]
Explain why it is important for plants to open and close their stomata in a daily rhythm.
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9700/43 · October/November 2024 · Q6a(ii)[3]
Homeostatic control of the water potential of blood includes receptors, effectors and target cells. Identify the names and locations of these components of homeostatic control in osmoregulation.
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9700/41 · May/June 2024 · Q3a[4]
Describe the mechanism by which stomata open in sunlight.
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9700/42 · May/June 2024 · Q1a(i)[1]
Name the location of osmoreceptors. (i)
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9700/42 · May/June 2024 · Q1a(ii)[1]
State the stimulus that is detected by osmoreceptors.
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9700/42 · May/June 2024 · Q1a(iii)[1]
Name the structure that secretes ADH into the blood.
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9700/42 · May/June 2024 · Q1b(i)[2]
As the concentration of ADH in the blood increases, the rate of production of urine decreases. Using Fig. 1.1, calculate the percentage decrease in the rate of production of urine between ADH concentrations of 1 and 3 arbitrary units. Show your working. Give your answer to one decimal place. answer =
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9700/42 · May/June 2024 · Q1b(ii)[3]
Explain the relationship shown in Fig. 1.1. ,
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9700/42 · May/June 2024 · Q10a[1]
In mammals, blood glucose concentration is maintained around a set point so that the mammal can function efficiently. This is an example of homeostasis. Name the mechanism that maintains blood glucose concentration around a set point.
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9700/42 · May/June 2024 · Q10b[3]
Fig. 10.1 shows how the blood glucose concentration varies before, during and after a period of exercise. 7 blood glucose concentration / mmol dm –3 period of exercise 6 5 4 0 10 20 30 40 50 60 70 80 90 100 time / min Fig. 10.1 Explain the results shown in Fig. 10.1 between 15 minutes and 70 minutes. ,
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9700/42 · May/June 2024 · Q10c(ii)[2]
Most people with diabetes mellitus use a biosensor to obtain their blood glucose concentration. Suggest the advantages of using a biosensor rather than test strips.
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9700/43 · May/June 2024 · Q6a[3]
In plants, stomata open and close in response to changes in environmental conditions. Explain why stomata need to open and close according to environmental conditions.
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9700/43 · May/June 2024 · Q6b[6]
Describe the mechanism occurring in guard cells that leads to the opening of a stoma.
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9700/21 · October/November 2023 · Q5a(ii)[2]
Describe the function of smooth muscle in the bronchus.
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9700/42 · May/June 2023 · Q9a[6]
The passage outlines the endocrine system. Complete the passage by using the most appropriate scientific terms. The endocrine system consists of tissues and , which secrete hormones such as insulin, glucagon and antidiuretic hormone (ADH). Glucagon only affects target cells that have complementary receptors, which are...
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What examiners said

Nearly all candidates were able to state the type of homeostatic control mechanism.
— Examiner report, February/March 2025, 9700/42 Q6(a)(ii) (Cambridge)

Many responses demonstrated a good understanding of the role of glucagon in controlling blood glucose concentrations. Strong responses described the main events in detail, starting with the binding of glucagon to a cell surface membrane receptor and continuing in the correct sequence. Weaker responses included many of the key points, such as the name of the hormone and the breakdown of glycogen,...
— Examiner report, February/March 2025, 9700/42 Q6(b) (Cambridge)

Most candidates who gained credit recognised that smooth muscle in the wall of the bronchus is able to contract, and a few were able to develop their answer to explain the role of contraction of the smooth muscle. Common errors were to confuse the function of smooth muscle with elastic tissue and describe stretch and recoil, or to suggest that the bronchus itself contracts rather than the smooth m...
— Examiner report, October/November 2023, 9700/21 Q5(a)(ii) (Cambridge)

Practise this topic

Answer these questions online and get each one marked against the official mark scheme, with what you missed and how to fix it.

Practise homeostasis

In the syllabus

14.1 Homeostasis in mammals

explain what is meant by homeostasis and the importance of homeostasis in mammals
explain the principles of homeostasis in terms of internal and external stimuli, receptors, coordination systems (nervous system and endocrine system), effectors (muscles and glands) and negative feedback
state that urea is produced in the liver from the deamination of excess amino acids
describe the structure of the human kidney, limited to: • fibrous capsule • cortex • medulla • renal pelvis • ureter • branches of the renal artery and renal vein
Identify, in diagrams, photomicrographs and electron micrographs, the parts of a nephron and its associated blood vessels and structures, limited to: • glomerulus • Bowman’s capsule • proximal convoluted tubule • loop of Henle • distal convoluted tubule • collecting duct
describe and explain the formation of urine in the nephron, limited to: • the formation of glomerular filtrate by ultrafiltration in the Bowman’s capsule • selective reabsorption in the proximal convoluted tubule
relate the detailed structure of the Bowman’s capsule and proximal convoluted tubule to their functions in the formation of urine
describe the roles of the hypothalamus, posterior pituitary gland, antidiuretic hormone (ADH), aquaporins and collecting ducts in osmoregulation continued

14.1 Homeostasis in mammals

14.2 Homeostasis in plants

explain that stomata respond to changes in environmental conditions by opening and closing and that regulation of stomatal aperture balances the need for carbon dioxide uptake by diffusion with the need to minimise water loss by transpiration
explain that stomata have daily rhythms of opening and closing
describe the structure and function of guard cells and explain the mechanism by which they open and close stomata
describe the role of abscisic acid in the closure of stomata during times of water stress, including the role of calcium ions as a second messenger

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