A person is diagnosed with type 2 diabetes. Their doctor explains that the pancreas is still producing insulin, but the body's cells no longer respond to it properly. Explain how insulin normally controls blood glucose concentration after a meal, and why a person with type 2 diabetes would have persistently high blood glucose levels.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Type 2 diabetes is a condition in which body cells become less sensitive to insulin. It is increasingly common and is linked to diet and lifestyle factors.
Model answer (5 marks)
After a meal blood glucose rises. The pancreas senses the rise and secretes insulin into the blood. Insulin binds to receptors on body cells and on liver cells, stimulating glucose uptake and storage as glycogen. This lowers the blood glucose concentration back to the normal range – a negative‑feedback loop. In type‑2 diabetes the cells are insulin‑resistant, so insulin cannot stimulate glucose uptake. Consequently glucose remains in the blood and the concentration stays high.
Examiner tips
- Use the sequence: rise → detection → insulin release → action on cells → return to normal
- Mention negative feedback explicitly
- Explain insulin resistance as the key defect
Common mistakes
- Confusing insulin with glucagon or omitting the negative‑feedback step
- Saying the pancreas stops producing insulin – it still produces it in type‑2 diabetes
Mark scheme (5 marks)
- After a meal, blood glucose concentration rises
- The pancreas detects the rise and releases insulin into the bloodstream
- Insulin causes body cells / liver cells to take up glucose from the blood
- Blood glucose concentration returns to / is maintained at the normal level (negative feedback)
- In type 2 diabetes, cells do not respond to insulin, so glucose cannot be taken up / blood glucose remains high
Key terms in this question
insulin · blood glucose concentration · pancreas · type 2 diabetes
Related
- All Edexcel A-Level Biology A: Salters-Nuffield (9BN0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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