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

WJEC GCSE Biology (Wales) — 2.5.3 Homeostasis · Explain · 4 marks · View as Markdown

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

A student skips breakfast and goes for a long run. By the end of the run, their blood glucose concentration has dropped below the normal level.

Model answer (4 marks)

The pancreas senses the fall in blood glucose concentration.
The pancreas releases glucagon.
Glucagon signals the liver to convert glycogen into glucose.
Blood glucose concentration rises back to the normal level.

Examiner tips

Use the sequence of events – pancreas → glucagon → liver glycogen → glucose release.
Show the cause–effect link between low glucose and glucagon release.
Include the final outcome – glucose rises to normal.
Use correct terminology: pancreas, glucagon, liver, glycogen, glucose.

Common mistakes

Mixing up insulin and glucagon.
Omitting the liver’s role in glycogenolysis.
Not stating that glucose concentration returns to normal.

Mark scheme (4 marks)

The pancreas detects the fall in blood glucose concentration
The pancreas releases glucagon
Glucagon causes the liver to convert glycogen into glucose
Blood glucose concentration returns to / rises back to the normal level

Key terms in this question

blood glucose concentration