Genetic engineering

• how are enzymes used to cut up or join DNA together?

  • restriction enzymes recognise specific sequences of DNA and cut DNA at these points
  • ligase enzyme used to join 2 pieces of DNA together
  • 2 different bits of DNA stuck together - recombinant DNA
• what is a vector?

  • something that is used to transfer DNA into a cell - 2 types - plasmids and viruses
  • plasmids - small, circular molecules of DNA that can be transferred between bacteria
  • viruses insert DNA into organisms they infect\
• how does genetic engineering work?

  • DNA you wish to insert is cut with a restrictive enzyme - vector DNA cut open using same restrictive enzyme
  • vector DNA and DNA your inserting - mixed together with ligase enzyme
  • ligase joins 2 pieces of DNA together to produce recombinant DNA
  • the recombinant DNA - inserted into other cells
  • these cells now use gene you inserted - make protein you want
  • transgenic bacteria - genes transferred from another species
• how do genetically modified plants improve food production?

  • crops can be genetically modified - increase food production - make resistant to insects or herbicides
  • making crops insect-resistant - farmers don't spray as many pesticides - so wildlife that doesn't eat the crop is not harmed - increases the crop yield making more food
  • making crop herbicide-resistant - farmers can spray their crops to kill weed without affecting the crop itself - increase crop yield
  • concern with growing GM plants - transplanted genes may get out into the environment or affect food chains or human health
  • some people are against genetic engineering - worry that changing organisms genes may create unforseen problems - pass onto future generations