Explain how the hormone insulin helps to regulate blood glucose concentration after a meal.

WJEC GCSE Biology (Wales) — 2.5.2 Hormonal coordination · Explain · 4 marks · View as Markdown

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

After eating a meal containing carbohydrates, the concentration of glucose in the blood rises above the normal level.

Model answer (4 marks)

The pancreas senses the rise in blood glucose and secretes insulin. Insulin acts on the liver and muscle cells, stimulating the conversion of glucose into glycogen for storage. It also increases glucose uptake by body cells, lowering the amount of glucose in the bloodstream. As a result, blood glucose concentration falls back to the normal set point, maintaining homeostasis.

Examiner tips

Mention the pancreas as the sensor and insulin as the hormone released
Explain the dual action: glycogen synthesis in liver/muscle and increased cellular uptake
Show that the outcome is a return to the normal glucose level
Use terms like "homeostasis" and "set point"

Common mistakes

Failing to name the pancreas as the glucose sensor
Confusing insulin with glucagon
Not linking increased uptake to a fall in blood glucose

Mark scheme (4 marks)

The pancreas detects the rise in blood glucose concentration and releases insulin
Insulin causes the liver (and muscle cells) to convert glucose into glycogen for storage
Body cells take up more glucose from the blood (increased uptake by cells)
Blood glucose concentration returns to the normal/set level (homeostasis maintained)

Key terms in this question

insulin · blood glucose concentration