# Explain how glucose moves from a high concentration in the small intestine into an epithelial cell, and then how it moves from a low concentration inside the epithelial cell into the bloodstream against a concentration gradient.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 1.6 Membranes and transport · Explain · 5 marks

> Glucose is absorbed in the small intestine. The concentration of glucose inside the epithelial cells lining the small intestine is lower than in the intestinal lumen, but higher than in the blood capillaries nearby.

## Mark scheme (5 marks)

1. Glucose moves from the small intestine into the epithelial cell by diffusion
2. Diffusion occurs because glucose moves from a high concentration (in the lumen) to a low concentration (in the epithelial cell) / down a concentration gradient
3. Glucose moves from the epithelial cell into the blood against a concentration gradient by active transport
4. Active transport requires energy (from respiration / ATP)
5. Active transport uses carrier proteins (in the cell membrane) to move glucose

## Key terms

- [concentration gradient](https://www.gradenine.co.uk/glossary/concentration-gradient)

## Related

- [Revision notes for Edexcel A-Level Biology A: Salters-Nuffield (9BN0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-glucose-moves-from-a-9af013f1) · Published by Druglandscape Ltd.