# Explain why large food molecules must be broken down before they can be used by the body.

> WJEC GCSE Biology (Wales) — 1.3.2 Digestion and absorption · Explain · 4 marks

## Mark scheme (4 marks)

1. Large food molecules are insoluble / too large to pass through the gut wall / into the bloodstream
2. Digestion breaks large insoluble molecules into smaller soluble molecules
3. Small soluble molecules can pass through the wall of the small intestine / be absorbed into the bloodstream
4. The absorbed molecules are then transported to cells / used for energy or growth or repair

## Related

- [Revision notes for WJEC GCSE 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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