Explain the steps involved in recombinant DNA technology.

1. 1 · Define. Recombinant DNA technology joins DNA from two sources and puts it into a host to make a useful product.
2. 2 · Name the tools.
   • Restriction enzymes: molecular scissors
   • DNA ligase: molecular glue
   • Vector: plasmid
   • Host: E. coli
3. 3 · Write the steps.
   • Isolate the desired gene
   • Cut the gene and the plasmid with the same restriction enzyme
   • Join them with ligase: recombinant DNA
   • Insert into E. coli (transformation)
   • Multiply and express; extract the product
4. 4 · Draw the flow. Gene, plasmid, recombinant plasmid, bacterium, many bacteria, insulin, all labelled.
5. 5 · Give an example. Human insulin is made in E. coli.
6. 6 · Link to daily life. Insulin for people with diabetes is now made this way.
7. 7 · Close in one line. rDNA technology lets microbes act as factories for human proteins.

Scoring tip: Name the enzyme or the vector at each step, and draw arrows between the stages.