Genetic Engineering

Cards (14)

  • Genetic engineering can be done by transferring a desirable gene from a donor organism into the genome of a recipient organism.
  • Genetic engineering can be carried out on plants and animals.
  • Usually the recipient organism is a bacterial cell because:
    • Bacterial DNA is easily manipulated.
    • Bacteria can reproduce very rapidly.
    The bacteria then have the ability to make whatever the desirable gene codes for, like insulin for example.
  • Before genetic engineering, insulin was obtained from pigs and cattle.
    Due to an increase in the number of diabetics, more insulin is required than ever before.
  • The human insulin gene is removed using a restriction enzyme.
  • A bacterial plasmid is cut open using the same restriction enzyme.
  • Restriction enzymes leave 'sticky ends', where one of the two DNA strands is longer than the other.
  • Using the same restriction enzyme to cut both the human DNA and bacterial plasmid results in complementary sticky ends that join by base pairing.
  • A different enzyme is used to join the insulin gene and the bacterial plasmid.
  • The bacterial plasmid containing the insulin gene is placed into a bacterial cell.
  • The bacterial cell is placed in a fermenter to allow reproduction under perfect conditions (warmth, moisture and oxygen).
  • Downstreaming occurs – this is when insulin is extracted, purified and packaged.
  • The pure insulin produced can be used to treat diabetes.
  • Advantages of genetically engineered insulin:
    • Not limited by the slaughter of animals.
    • Large quantities can be made quickly.
    • No risk of transferring infections.
    • More effective at treating diabetes as animal insulin is different to human insulin.
    • No ethical issues concerning the use of animals