# A mutation occurs in a gene, changing one DNA base. Explain how this mutation could result in a non-functional protein being produced.

> AQA A-Level Biology (7402) — 3.4.2 DNA and Protein Synthesis · Explain · 5 marks

> Mutations are changes to the sequence of bases in DNA. Some mutations alter the protein that is produced from that gene.

## Mark scheme (5 marks)

1. A mutation changes the sequence of bases in the DNA / gene
2. The altered DNA is transcribed to produce a different / altered mRNA sequence
3. The changed mRNA codon codes for a different amino acid
4. The sequence of amino acids in the protein is changed / different
5. The protein folds into a different shape so it cannot function / active site shape is changed so it cannot work

## Key terms

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

## 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/a-mutation-occurs-in-a-gene-07d56cfb) · Published by Druglandscape Ltd.