Explain how the body responds when blood glucose concentration falls below the optimum level. In your answer, name the hormone involved and describe its effect on the liver.

Eduqas A-Level Biology — 4.2 Inheritance · Explain · 5 marks · View as Markdown

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

After a long period without eating, the concentration of glucose in a person's blood drops below the normal level.

Model answer (5 marks)

The pancreas senses the low blood glucose level.
The pancreas releases the hormone glucagon.
Glucagon circulates in the blood to the liver.
Glucagon stimulates the liver to break down glycogen into glucose.
The released glucose raises blood glucose back to the normal level, completing negative feedback.

Examiner tips

  • Use the exact terms: pancreas, glucagon, liver, glycogen, glucose, negative feedback.
  • Show the sequence of events in order.
  • Mention that glucagon is a hormone.
  • Keep the answer concise – one sentence per point.

Common mistakes

  • Confusing insulin with glucagon.
  • Failing to state that glucagon acts on the liver.
  • Omitting the negative feedback loop.

Mark scheme (5 marks)

  1. The pancreas detects the fall in blood glucose concentration
  2. The pancreas releases / secretes glucagon
  3. Glucagon travels in the blood to the liver (as a chemical messenger / hormone)
  4. Glucagon causes the liver to convert glycogen into glucose
  5. Blood glucose concentration rises back to the optimum / normal level (negative feedback)

Key terms in this question

blood glucose concentration

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