A person with type 1 diabetes does not produce insulin. They inject insulin before eating a meal. Explain why injecting insulin before a meal helps to maintain a stable blood glucose concentration.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Type 1 diabetes is a condition in which the pancreas does not produce insulin. People with type 1 diabetes must inject insulin to regulate their blood glucose concentration.
Model answer (5 marks)
1. Eating a meal raises blood glucose concentration.
2. Insulin is the hormone that lowers blood glucose concentration.
3. Insulin causes glucose to be taken up by cells and converted to glycogen in the liver and muscles.
4. This removes excess glucose from the blood, returning the concentration to the normal set point.
5. The process is an example of negative feedback, maintaining a stable internal environment (blood glucose).
2. Insulin is the hormone that lowers blood glucose concentration.
3. Insulin causes glucose to be taken up by cells and converted to glycogen in the liver and muscles.
4. This removes excess glucose from the blood, returning the concentration to the normal set point.
5. The process is an example of negative feedback, maintaining a stable internal environment (blood glucose).
Examiner tips
- Use the exact terminology: insulin, glycogen, negative feedback. Show the sequence: meal → ↑ glucose → insulin → ↓ glucose. Include the word ‘set point’ to demonstrate understanding of homeostasis.
Common mistakes
- Forgetting to mention the conversion to glycogen. Using ‘increase’ instead of ‘rise’ for blood glucose. Not linking the process to negative feedback/homeostasis.
Mark scheme (5 marks)
- Eating a meal causes blood glucose concentration to rise / increase
- Insulin is the hormone that lowers blood glucose concentration
- Insulin causes glucose to be converted to glycogen (in the liver / muscles)
- This removes excess glucose from the blood, returning blood glucose concentration to normal / the set point
- This is an example of negative feedback / homeostasis, which maintains a stable internal environment / stable blood glucose concentration
Key terms in this question
insulin · blood glucose concentration
Related
- All Pearson Edexcel A-Level Biology A (9BI0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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