# Describe the structure of a lipid molecule and explain why lipids are important in the human body.

> AQA A-Level Biology (7402) — 3.1.3 Lipids · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. A lipid is made of one glycerol molecule
2. A lipid is made of three fatty acid molecules joined to the glycerol
3. Lipids are used as a store of energy / provide energy when respired
4. Lipids are used for insulation (to keep the body warm) / thermal insulation
5. Lipids are used to make cell membranes

## Key terms

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

## Related

- [Revision notes for AQA A-Level Biology (7402)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-structure-of-a-lipid-8a4e9d03) · Published by Druglandscape Ltd.