Homeostasis — AS & A Level Biology (9700) questions by topic
Kidney structure and glucose-regulation hormones drive this topic: labelling the glomerulus and Bowman's capsule on a photomicrograph, explaining how factors such as blood pressure affect glomerular filtration rate, and outlining the sequence by which glucagon raises blood glucose in liver cells. Explain, suggest and identify lead the command words, and explain wants a mechanism, such as sodium ion movement across the nephron, rather than a labelled outcome alone.
With 18 real questions from 2023 to 2025 papers, marks here run unusually high for a single-topic set, from 8 to 15, reflecting the multi-step nature of kidney and hormone questions. Practising full-sequence explanations with instant marking is well suited here, since a step described out of order in glucagon signalling is caught immediately.
What examiners look for
- A frequent error mislabels the glomerular filtrate and blood plasma locations on a Bowman's capsule photomicrograph.
- Reports note some candidates placing labels directly on the image instead of using label lines as instructed.
- Answers on glomerular filtration rate often list contributing factors without explaining how each factor changes the rate.
- A common gap omits detail such as sodium ions being pumped out of cells, or returning from the lumen or filtrate, in nephron-function answers.
- Strong answers correctly identify an increase in blood pressure or hydration raising glomerular filtration rate, and sequence glucagon's liver-cell effects in the correct order.
May–June 2025, Paper 41
In the kidney, various molecules move between the blood and the kidney nephron. Table 6.1 describes the movements of molecules at three regions of the nephron, P, Q and R: - P:…
Answer this question and get it marked →Insulin is an example of a cell-signalling molecule of the endocrine system. Outline why insulin can be described as an example of a cell-signalling molecule of the endocrine…
Answer this question and get it marked →May–June 2025, Paper 43
The kidneys have a role in excretion and in osmoregulation. Excretion is the removal of the waste products of metabolism or the removal of substances that are in excess. Name the…
Answer this question and get it marked →May–June 2025, Paper 44
The kidneys play a role in osmoregulation. Antidiuretic hormone (ADH) is involved in osmoregulation. Describe how a decrease in blood water potential leads to an increase in ADH…
Answer this question and get it marked →May–June 2024, Paper 41
Coordination in humans involves two main systems: the nervous system and the endocrine system. Paracrine cell signalling is a third way in which coordination occurs. In paracrine…
Answer this question and get it marked →May–June 2024, Paper 42
Osmoregulation is the control of the water potential of body fluids such as blood. Osmoreceptors and antidiuretic hormone (ADH) have an important role in osmoregulation. Name the…
Answer this question and get it marked →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…
Answer this question and get it marked →May–June 2024, Paper 43
Fig. 1.1 outlines the effect of antidiuretic hormone (ADH) on the cells of the collecting duct. The cell-signalling mechanism of ADH is similar to that of glucagon on liver cells.…
Answer this question and get it marked →October–November 2024, Paper 42
Fig. 1.1 is a diagram of part of a Bowman's capsule and a glomerular capillary. Label A points to a cell of the Bowman's capsule wall with finger-like processes; label B points to…
Answer this question and get it marked →Blood glucose concentration is maintained around a set point by homeostasis. Explain the principles of homeostasis.
Answer this question and get it marked →October–November 2024, Paper 43
The mammalian kidney is responsible for: the excretion of urea; osmoregulation (the homeostatic control of the water potential of the blood). Outline how and where the excretory…
Answer this question and get it marked →February–March 2023, Paper 42
Fig. 1.1 is a drawing of a longitudinal section (LS) of a human kidney, with four regions labelled A, B, C and D (A = cortex, B = pelvis, C = medulla, D = ureter). Use the letters…
Answer this question and get it marked →May–June 2023, Paper 41
Fig. 5.1 is a photomicrograph of part of a kidney nephron (magnification x900), with two structures labelled A and B. Identify the structures labelled A and B in Fig. 5.1.
Answer this question and get it marked →May–June 2023, Paper 42
Fig. 6.1 is a photomicrograph of a section through a Bowman's capsule and a glomerulus. On Fig. 6.1, use label lines and letters to label: F - the location of the glomerular…
Answer this question and get it marked →The passage outlines the endocrine system. Complete the passage by using the most appropriate scientific terms. 'The endocrine system consists of tissues and .........., which…
Answer this question and get it marked →May–June 2023, Paper 43
Fig. 6.1 shows part of the Bowman's capsule of a kidney nephron (not to scale). It shows the lumen of a capillary and the lumen of the Bowman's capsule, with three structures…
Answer this question and get it marked →October–November 2023, Paper 42
When blood glucose concentration decreases, glucagon is released by the pancreas into the blood and transported to the cells. Fig. 6.1 outlines the effect of glucagon on liver…
Answer this question and get it marked →Antidiuretic hormone (ADH) is involved in the maintenance of a constant blood water potential. A student drank 0.5 dm³ of water and the concentration of ADH in their blood was…
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