# A gene is made up of a sequence of DNA bases. Explain how the sequence of bases in a gene determines the structure of a specific protein.

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

## Mark scheme (5 marks)

1. The sequence of bases in DNA codes for the sequence of amino acids (in a protein)
2. Every three bases (a triplet / codon) codes for one amino acid
3. A copy of the gene is made as mRNA (transcription) / the DNA code is copied into mRNA
4. mRNA moves to a ribosome where the protein is assembled (translation)
5. Amino acids are joined together in a specific sequence to form a protein / the order of amino acids determines the shape and function of the protein

## Key terms

- [gene](https://www.gradenine.co.uk/glossary/gene)
- [DNA bases](https://www.gradenine.co.uk/glossary/dna-bases)
- [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-gene-is-made-up-of-3ed6d006) · Published by Druglandscape Ltd.