natural selection (paper 1)

Question 1

genetic engineering for human insulin

Answer 1

• restriction enzymes make staggered cuts across the double stranded DNA, leaving sticky ends
• the same restriction enzymes cut plasmids open, leaving the sticky ends with matching sets of unpaired bases
• pieces of DNA containing the insulin gene are mixed with plasmids
• bases in the sticky ends pair up
• DNA ligase (enzyme) is added, linking the DNA back into a continous circle
• plasmids are inserted into the bacteria, and can now be grown in huge fermenters where they make human insulin