# A cell in the pancreas produces the protein insulin. Describe the roles of DNA, messenger RNA (mRNA) and ribosomes in producing the insulin protein, starting from the gene in the nucleus.

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

> Insulin is a protein hormone made up of a specific sequence of amino acids. It is produced in specialised cells of the pancreas and released into the blood to regulate blood glucose concentration.

## Mark scheme (5 marks)

1. The gene (section of DNA) contains a sequence of bases that codes for the insulin protein
2. The base sequence of the gene is used as a template to make a complementary strand of mRNA (transcription)
3. The mRNA moves out of the nucleus to a ribosome in the cytoplasm
4. The ribosome reads the mRNA base sequence in groups of three bases (codons) / each codon codes for a specific amino acid
5. Amino acids are joined together in a specific sequence to form the insulin protein (translation)

## Key terms

- [gene](https://www.gradenine.co.uk/glossary/gene)
- [DNA](https://www.gradenine.co.uk/glossary/dna)
- [messenger RNA (mRNA)](https://www.gradenine.co.uk/glossary/messenger-rna-mrna)
- [ribosome](https://www.gradenine.co.uk/glossary/ribosome)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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-cell-in-the-pancreas-produces-25372065) · Published by Druglandscape Ltd.