# Describe the roles of carbohydrates and fats in the human body.

> WJEC GCSE Biology (Wales) — 1.3.1 Diet and nutrition · Describe · 4 marks

## Mark scheme (4 marks)

1. Carbohydrates are used as a source of energy (for respiration / metabolic processes).
2. Excess carbohydrates can be stored (as glycogen in the liver/muscles OR converted to fat for storage).
3. Fats are used as an energy store / provide energy (when carbohydrate reserves are low).
4. Fats are used for insulation (to reduce heat loss) OR to make cell membranes OR to protect organs.

## Key terms

- [carbohydrates](https://www.gradenine.co.uk/glossary/carbohydrates)
- [fats](https://www.gradenine.co.uk/glossary/fats)

## Related

- [Revision notes for WJEC GCSE Biology (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/describe-the-roles-of-carbohydrates-and-97b3072f) · Published by Druglandscape Ltd.