# A student is investigating how proteins are made in a cell. Explain how the sequence of bases in a gene determines the structure of a specific protein, including the roles of transcription and translation in this process.

> OCR A-Level Biology B — Advancing Biology (H422) — 5.1 Genetic control of protein synthesis · Explain · 5 marks

> Proteins are made by cells following instructions stored in the DNA. The process involves two key stages that take place in different parts of the cell.

## Mark scheme (5 marks)

1. A gene is a section of DNA that codes for a specific amino acid sequence
2. During transcription, the DNA is unzipped and a copy is made as mRNA in the nucleus
3. The mRNA carries the genetic information from the nucleus to the ribosomes
4. During translation, the mRNA sequence is used to join amino acids in the correct order at the ribosome
5. The amino acids are polymerised to form a specific protein with a particular structure/function

## Key terms

- [gene](https://www.gradenine.co.uk/glossary/gene)
- [transcription](https://www.gradenine.co.uk/glossary/transcription)
- [translation](https://www.gradenine.co.uk/glossary/translation)

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](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-is-investigating-how-proteins-58e08028) · Published by Druglandscape Ltd.