A person eats a large meal containing a lot of sugar. Their blood glucose concentration rises. Explain how the body responds to return blood glucose concentration to its normal level.

OCR A-Level Biology B — Advancing Biology (H422) — 5.5 Communication and homeostasis · Explain · 5 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

The human body constantly monitors and adjusts its internal conditions. Blood glucose concentration is one of the conditions that must be kept within a narrow range for cells to function properly.

Model answer (5 marks)

The pancreas senses the increased glucose level in the blood.
The pancreas secretes insulin into the bloodstream.
Insulin stimulates the liver (and muscle cells) to take up glucose and convert it into glycogen for storage.
The uptake and storage of glucose lowers the blood glucose concentration.
This is a negative‑feedback response that counteracts the initial rise and restores the normal level.

Examiner tips

  • Use the word ‘secretes’ for insulin, not ‘produces’.
  • Show the sequence: detection → insulin release → glycogen synthesis → glucose fall.
  • Mention ‘negative feedback’ explicitly to hit the final point.

Common mistakes

  • Saying the pancreas ‘produces’ insulin instead of ‘secretes’. Forgetting to state that insulin acts on the liver and muscle cells. Omitting the negative‑feedback terminology.

Mark scheme (5 marks)

  1. The pancreas detects the rise in blood glucose concentration
  2. The pancreas releases / secretes insulin
  3. Insulin causes the liver (and muscle cells) to convert glucose into glycogen for storage
  4. Blood glucose concentration falls / returns to the normal level
  5. This is an example of negative feedback — the response opposes / counteracts the original change to restore the normal level

Key terms in this question

blood glucose concentration

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