# Explain how a molecule of DNA in a cell nucleus controls the sequence of amino acids in a protein that is assembled in the cytoplasm.

> AQA A-Level Biology (7402) — 3.1.5 Nucleic Acids · Explain · 5 marks

## Mark scheme (5 marks)

1. DNA / gene contains a sequence of bases (that codes for a protein)
2. The base sequence is transcribed / copied into mRNA
3. mRNA moves out of the nucleus / to the ribosome (in the cytoplasm)
4. Each three bases (codon) on the mRNA codes for one specific amino acid
5. tRNA carries / brings the correct amino acid to the ribosome, so the sequence of bases determines the sequence of amino acids in the protein

## Key terms

- [DNA](https://www.gradenine.co.uk/glossary/dna)
- [amino acid](https://www.gradenine.co.uk/glossary/amino-acid)

## 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/explain-how-a-molecule-of-dna-f40abe1a) · Published by Druglandscape Ltd.