A patient with Type 1 diabetes does not produce insulin. Explain why this patient must inject insulin before eating a meal containing carbohydrates.

Edexcel GCSE Biology (1BI0) — 7.2 Homeostasis · Explain · 4 marks · View as Markdown

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

Model answer (4 marks)

Carbohydrates are broken down to glucose, raising blood glucose concentration.
Insulin is required for liver and muscle cells to take up glucose from the blood.
Insulin also stimulates the conversion of glucose to glycogen in the liver.
Without insulin the blood glucose level would stay high, so glucose homeostasis would be lost.

Examiner tips

  • Use the exact terms ‘insulin’, ‘glucose uptake’, ‘glycogen synthesis’, and ‘homeostasis’. Show the cause–effect chain: digestion → glucose rise → insulin action → uptake/glycogen → normal glucose level. Keep the answer concise to fit the 4 marks.

Common mistakes

  • Confusing insulin with glucagon or omitting the liver‑muscle uptake point. Failing to mention that glucose would remain too high if insulin is absent.

Mark scheme (4 marks)

  1. Carbohydrates are digested to glucose, causing blood glucose concentration to rise
  2. Insulin causes liver and muscle cells to increase their uptake of glucose
  3. Insulin causes conversion of glucose to glycogen in the liver
  4. Without insulin, blood glucose concentration would remain too high / homeostasis of blood glucose would not be maintained

Key terms in this question

insulin

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