O-Level Molecular Genetics: worked solution

Question

A further instance of a genetically modified organism is the engineering of E. coli bacteria so that they manufacture human insulin. Describe the steps by which E. coli can be genetically altered so that it produces human insulin.

The human insulin gene is first cut out of human DNA using a restriction enzyme. A bacterial plasmid (the vector) is cut open with the same restriction enzyme, producing complementary sticky ends. The insulin gene is inserted into the plasmid and sealed in place using ligase enzyme, forming a recombinant plasmid. This recombinant plasmid is then taken up by an E. coli bacterium. The bacteria are cultured/grown in a fermenter and multiply; they transcribe and translate the inserted gene to make human insulin, which is then extracted and purified.