Explain how the body responds when blood glucose concentration falls below the normal level.

Edexcel GCSE Biology (1BI0) — 7.2 Homeostasis · Explain · 4 marks · View as Markdown

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

During a long-distance run, a person's body uses up glucose rapidly. After a period of time, blood glucose concentration falls below the normal level.

Model answer (4 marks)

The pancreas senses the low blood glucose level and releases glucagon.
Glucagon stimulates the liver to break down glycogen into glucose.
The glucose is released into the bloodstream, raising the blood glucose concentration.
This process restores the normal glucose level, maintaining homeostasis.

Examiner tips

  • Use the word ‘secretes’ for glucagon, not ‘produces’.
  • Show the sequence: pancreas → glucagon → liver glycogen breakdown → glucose release → rise in blood glucose.
  • Mention that this is a negative feedback loop that keeps the internal environment stable.

Common mistakes

  • Confusing glucagon with insulin.
  • Failing to mention the liver as the site of glycogen breakdown.
  • Omitting that the process restores normal glucose levels (homeostasis).

Mark scheme (4 marks)

  1. The pancreas detects the low blood glucose concentration and secretes glucagon
  2. Glucagon causes the breakdown of glycogen to glucose in the liver
  3. Glucose is released into the bloodstream, raising blood glucose concentration
  4. This is an example of homeostasis / maintaining a stable internal environment

Related

More Homeostasis questions

▶ Try answering this question with AI marking (free) →