# Describe the main difference between a polypeptide chain and a protein.

> AQA A-Level Biology (7402) — 3.1 Biological Molecules · Describe · 4 marks

## Mark scheme (4 marks)

1. Understanding of the definition of a polypeptide chain
2. Understanding of the definition of a protein
3. Explanation of the main difference between a polypeptide chain and a protein
4. Understanding of the functional significance of the difference

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-main-difference-between-a-d65c0fe4) · Published by Druglandscape Ltd.