use of biological resources

• 1. Equipment is sterilised to kill unwanted microorganisms and prevent contamination.
  2. Milk is pasteurised at 72°C for 15 seconds to kill harmful microorganisms.
  3. Milk is cooled and Lactobacillus bacteria is added.
  4. Incubated at 40-45°C for several hours. During this time the Lactobacillus bacteria ferment the lactose in the milk.
  5. The Lactobacillus bacteria convert the lactose into lactic acid, which sours and thickens the milk, forming yoghurt.
  6. The yoghurt is then stirred and cooled - halting the action of the Lactobacillus bacteria.
  7. Flavourings, colorants, and fruit may be added before packaging.
• 1. Plant with desirable characteristic is selected to be cloned. Explants are taken from the tips of the stems / side shoots.
  2. explants are sterilised to kill microorganisms
  3. explants are then grown in vitro - they're placed in a petri dish containing nutrient medium for the plant to grow.
  4. Cells in the explants divide and grow into a small plant. This continues until enough small plants are produced.
  5. the small plants are taken out fo the medum, planted in soil and put into glasshousesses - they'll develop into plants that are genetically identical to the original plant.
• Cloning an adult mammal:

  1. nucelus of a sheep's egg cell is removed creating an enucleated cell (egg without a nucleus)
  2. Diploid nucelus (full set of paired chromosomes) was inserted in its place. This is a nucelus from a mature udder cell of a different sheep.
  3. The cell was stimulated (by an electric shock) so that it starts dividing by mitosis like a normal fertlised cell.
  4. The dividing cell was implanted into the uterus of another sheep to develop until it is ready to give be born.
• • Fish are kept in cages in the sea so they don't use as much energy
  • The cage also protects interspecific predation
  • They are fed food pellets that is carefully controlled to maximise the amount of energy they get. This is so they can get bigger faster.
  • Big fish must be separate from small fish to prevent intraspecific predation (eating individuals of hte same species)
  • Fish kept in cages are more prone to disease and parasites (eg. sea lice).
  • to avoid chemical pollution from pesticides, biological pest controls are used.
  • selectively bred to produce less aggressive, faster growing fish
• nitrogen fixing --> nitrogen gas to ammonia

  nitrifying -->ammonia to nitrate

  denitrifying --> nitrate to nitrogen gas and reduces nitrogen available to plants