# Proteins are polymers made from monomers called amino acids. Explain how a protein polymer is formed from amino acid monomers, and explain how the protein can be broken down again to release individual amino acids.

> AQA A-Level Biology (7402) — 3.1.1 Monomers and Polymers · Explain · 5 marks

## Mark scheme (5 marks)

1. Amino acids are the monomers that join together to form a protein polymer
2. Many amino acids join together (by chemical bonds) to form the polymer / large molecule
3. The process of joining monomers together requires a chemical reaction
4. The protein polymer can be broken down by digestion / hydrolysis
5. Water is used / added to break the bonds during hydrolysis / digestion

## Key terms

- [monomer](https://www.gradenine.co.uk/glossary/monomer)
- [polymer](https://www.gradenine.co.uk/glossary/polymer)
- [amino acid](https://www.gradenine.co.uk/glossary/amino-acid)

## Related

- [Revision notes for AQA A-Level Biology (7402)](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/proteins-are-polymers-made-from-monomers-bb204647) · Published by Druglandscape Ltd.