# Red blood cells need glucose for cellular respiration. Explain how glucose moves from the blood plasma into a red blood cell, and describe what happens to the rate of this movement when glucose concentration in the plasma is very high compared to inside the cell.

> WJEC A-Level Biology (Wales) — 1.3 Cell membranes and transport · Explain · 5 marks

> Red blood cells lack mitochondria and rely entirely on glucose obtained from the surrounding blood plasma to carry out cellular respiration.

## Mark scheme (5 marks)

1. Glucose moves by diffusion (across the cell membrane)
2. Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration
3. The cell membrane is selectively permeable / controls what enters and exits the cell
4. When glucose concentration in the plasma is very high compared to inside the cell, the concentration gradient is steeper / larger
5. A steeper concentration gradient means glucose diffuses into the cell at a faster rate

## Key terms

- [cellular respiration](https://www.gradenine.co.uk/glossary/cellular-respiration)

## Related

- [Revision notes for WJEC A-Level Biology (Wales)](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/red-blood-cells-need-glucose-for-c1e74b66) · Published by Druglandscape Ltd.