Explain how genetic engineering can be used to produce a crop plant that is resistant to insect damage.

Edexcel GCSE Biology (1BI0) — 4.3 Selective breeding and genetic engineering · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

A restriction enzyme cuts the insect‑resistance gene from the donor DNA, creating sticky ends.
The gene is inserted into a plasmid vector and DNA ligase joins the sticky ends to form recombinant DNA.
The recombinant plasmid is transferred into crop plant cells, for example by Agrobacterium or particle bombardment.
The plant cells take up the plasmid, express the resistance gene and produce a crop plant that is resistant to insect damage.

Examiner tips

  • Use the term ‘restriction enzyme’ and ‘sticky ends’ – these are key words. Show the step of ligase joining the ends. Mention the vector and the method of transfer. Keep the answer concise and in the correct order.

Common mistakes

  • Omitting the role of ligase. Using ‘cutting’ without specifying restriction enzyme. Failing to mention the vector or transfer method.

Mark scheme (4 marks)

  1. A restriction enzyme is used to cut the desired gene (e.g. the gene for insect resistance) from the donor organism's DNA
  2. This produces sticky ends on the DNA fragment
  3. The gene is inserted into a vector, and ligase joins the sticky ends to form recombinant DNA
  4. The recombinant DNA / vector is transferred into the crop plant cells so the plant expresses the desired characteristic (insect resistance)

Key terms in this question

genetic engineering

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