# Explain how a mutation in a gene may affect the phenotype of an organism.

> Eduqas GCSE Biology — 7.3 Variation and evolution · Explain · 4 marks

## Mark scheme (4 marks)

1. A mutation is a random change in DNA / the base sequence of DNA
2. This alters the sequence of amino acids coded for / changes which amino acids are joined together during protein synthesis
3. This produces a different / altered protein (structure)
4. The changed protein may alter the physical characteristics of the organism / affect the phenotype; the effect may be neutral, beneficial or damaging

## Key terms

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

## Related

- [Revision notes for Eduqas GCSE Biology](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/explain-how-a-mutation-in-a-b1ae53a7) · Published by Druglandscape Ltd.