# A student learns that a mutation in a gene can sometimes result in a non-functional protein being made. Explain how a change in the base sequence of a gene can lead to a different protein being produced.

> Pearson Edexcel A-Level Biology A (9BI0) — 1.4 DNA, RNA and protein synthesis · Explain · 5 marks

> Proteins are made using information stored in DNA. The sequence of bases in a gene acts as a code that is used during protein synthesis to join amino acids in a specific order.

## Mark scheme (5 marks)

1. DNA contains a sequence of bases that codes for a specific sequence of amino acids
2. A mutation changes the base sequence of the gene
3. The altered base sequence is transcribed into mRNA, producing a different mRNA sequence
4. The altered mRNA is translated at the ribosome, causing a different amino acid to be added
5. A different sequence of amino acids results in a different-shaped (tertiary) structure / non-functional protein

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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-student-learns-that-a-mutation-d266c7bb) · Published by Druglandscape Ltd.