BIO2

• Memorable biology labs


  • Bacteria given a gene from a bioluminescent jellyfish, causing them to glow under UV light
• Bacteria can be given a human gene, like the gene for insulin
• Insulin


  A hormone made by the pancreas that helps cells get the glucose they need
• Type 1 Diabetes


  A condition where the pancreas doesn't make enough insulin, so the individual must take insulin injections
• Producing insulin in a lab using bacteria

  1. Bacteria are given the human gene for insulin

  2. Bacteria produce the insulin

  3. Insulin is purified and used for those with Type 1 Diabetes
• Transformation


  The process where a cell, commonly bacteria, can take up DNA from their environment and use that DNA
• Genetic engineering


  Changing an organism's genotype using biotechnology tools or techniques
• Human cell


  • Contains a nucleus with the organism's entire DNA code
  • Most body cells contain all of your DNA
• Plasmid


  An extra set of genes, in addition to the bacterial chromosome, that bacteria can use
• Inserting a gene into a plasmid

  1. Use restriction enzymes to cut the plasmid

  2. Use ligase to seal the human insulin gene into the plasmid
• Recombinant DNA


  DNA containing DNA from different sources
• Transgenic


  Any organism or microorganism that has genetic material from some other organism
• Vector


  The vehicle for getting recombinant DNA into an organism, e.g. plasmids or viruses
• Genetic engineering vectors


  • Plasmids
  • Viruses
• Microinjection


  Injecting a gene of interest through the cytoplasm of a cell and into its nucleus
• Gene guns


  Shooting particles coated with recombinant DNA into cells, helpful for thick cell walls
• CRISPR


  A gene editing tool that uses a special nuclease called Cas9 to cut DNA at specific target sites
• Uses of genetic engineering

  • Medical applications (insulin, clotting factors, human growth hormone)
  • Agricultural applications (pest/herbicide/drought resistant crops, plants that remove pollutants)
  • Research applications (genetically engineered mice)
• There are ethical considerations that must be examined for genetic engineering
• GM crops


  Crops given extra genes for new and useful characteristics
• Useful characteristics in crops

  • Pest resistance
  • Frost resistance
  • Disease resistance
  • Herbicide resistance
  • Drought resistance
  • Longer shelf life
• Pest-resistant crops


  • Potatoes genetically modified to be toxic to pests like the Colorado beetle
  • Gene for a powerful bacterial toxin added to the potato plant
  • Kills the pest if it tries to eat the potato plant
• Pest-resistant crops


  Benefits for the environment
• Frost-resistant crops


  • Crops genetically modified to be resistant to adverse environmental conditions
  • Example: Lettuces genetically modified to be frost resistant
• Some people are against the development and use of GM crops
• Plants with extra vitamins


  • Rice genetically modified to make beta-carotene, a substance converted to vitamin A
  • Called "Golden Rice" and developed to help fight vitamin A deficiency and blindness in developing countries
• Selective breeding


  • A simple form of genetic engineering done for thousands of years
  • Selecting and breeding only those plants and animals with desirable characteristics
• Selective breeding


  • Breeding sheep to produce more wool
  • Breeding wheat to produce more grain
  • Breeding tomatoes to have more flavour
  • Breeding racing horses to become faster
  • Breeding dogs to obtain unique characteristics
• Changing the genetic code

  • Bacteria often genetically engineered to produce useful chemicals
  • Their DNA is loose in the cytoplasm, making it easy to modify
  • They grow and replicate quickly
• Using viruses


  • Viruses cannot read their own genes but can make a host cell copy them and make the proteins
  • Bacteriophages infect bacteria by injecting material down a special tube
  • Viruses are useful in genetic engineering
• Genetically-engineered micro-organisms


  Bacteria and yeast that can easily be replicated on a large scale
• Fermenters or bioreactors


  • Tanks used to grow or 'culture' micro-organisms at optimum pH, temperature and nutrient levels
• Making bacteria produce a human protein

  1. Identify the gene for the human protein

  2. Insert the modified plasmid into the bacterium

  3. Insert the gene into the plasmid

  4. Bacteria produce the required protein

  5. Add the bacterium to a fermenter and replicate
• Bacterial plasmid


  Cut open with enzymes to remove the gene
• Genetically-engineered bacteria are unable to make proteins that are identical to those found naturally in humans, despite having human DNA
• Mammalian cells


  Grown in industrial bioreactors to produce proteins that are identical to the ones found in humans
• Transgenics


  Foreign DNA, including DNA from humans, can be inserted into animals
• Transgenic animals


  • The protein encoded by the inserted DNA can be produced in a specific tissue at a specific time
  • This method produces higher levels of antibody, more easily and cheaply, than by using genetically-engineered bacteria or mammalian cells
• Transgenic goats


  • The gene for a human antibody can be introduced, along with additional controlling DNA, so the antibody is only produced in the goat's mammary gland at a certain time
  • The antibody is then expressed in the goat's milk, where it can be purified and used to treat diseases
• Transgenic chickens


  • The eggs contain a human antibody that could one day help to treat skin cancer