# Describe the role of restriction enzymes, plasmids, and ligase in the genetic modification of bacteria to produce insulin.

> Pearson Edexcel International GCSE Biology (4BI1) — 5.3 Genetic modification (genetic engineering) · Describe · 4 marks

> Genetic modification is used to produce human insulin from bacteria grown in fermenters. The process involves transferring the human insulin gene into bacterial cells.

## Mark scheme (4 marks)

1. Restriction enzymes cut DNA at specific regions to isolate the insulin gene from the human chromosome
2. The insulin gene is inserted into a plasmid (loop of DNA found in the cytoplasm of prokaryotic cells) to form recombinant DNA
3. Ligase joins / seals the insulin gene into the plasmid (joining the pieces of DNA together)
4. The plasmid (vector) transfers the recombinant DNA into the bacterial host cell, which then produces insulin

## Key terms

- [restriction enzymes](https://www.gradenine.co.uk/glossary/restriction-enzymes)
- [plasmids](https://www.gradenine.co.uk/glossary/plasmids)
- [ligase](https://www.gradenine.co.uk/glossary/ligase)
- [insulin](https://www.gradenine.co.uk/glossary/insulin)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-role-of-restriction-enzymes-706f7375) · Published by Druglandscape Ltd.