Genetic Engineering

The general process

  1. The DNA for the desired gene is isolated in the donor cell (this can be isolated on the mRNA molecule or on a section of DNA).
  2. A restriction endonuclease is used to cut the gene from the DNA:
    This leaves “sticky ends” on the gene (single strands of base sequences ready to hydrogen bond with complimentary bases.
  3. The same restriction endonuclease is used to cut a section of DNA from a plasmid; this leaves complimentary base ends for the isolated gene to bond to.
  4. The plasmids are then taken up by the host cells.
  5. The plasmid also contained a marker gene (this could have been a gene for antibiotic resistance, therefore the bacteria can be grown in antibiotics and any cell that hasn’t got the new plasmid will die).
  6. The bacteria cells multiply in a fermenter. If the new gene was for insulin production, the insulin would be produced within the fermenter and isolated later on.

What is genetic engineering being used for?


Waste management and pollution control


Pest and weed control

Selective plant breeding

Example of Genetic Engineering

Useful books for revision

Revise A2 Chemistry for Salters (OCR A Level Chemistry B)
Salters (OCR) Revise A2 Chemistry