# Ribosomes are found in all living cells. Explain the role of ribosomes in protein synthesis, including how the sequence of amino acids in a protein is determined.

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

> Every protein in an organism is assembled at a ribosome. The order in which amino acids are joined together determines the final shape and function of the protein.

## Mark scheme (5 marks)

1. Ribosomes are the site where proteins are made / assembled
2. mRNA carries the genetic code from the nucleus to the ribosome
3. The ribosome reads the sequence of bases on the mRNA
4. Each sequence of three bases (a codon / triplet) codes for a specific amino acid
5. Amino acids are joined together in a specific order / sequence to form a protein (polypeptide)

## Key terms

- [ribosome](https://www.gradenine.co.uk/glossary/ribosome)
- [amino acid](https://www.gradenine.co.uk/glossary/amino-acid)
- [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/ribosomes-are-found-in-all-living-61463ba1) · Published by Druglandscape Ltd.