microorganisms and biotechnology

• why are microorganisms ideal for biotechnology?

  • they have a short life cycle so a rapid growth rate, huge amounts of organisms can be produced in a short amount of time
  • nutrient requirements of the organisms are simple and quite cheap to generate. Also organisms can be modified so that they can utilise materials which would otherwise be wasted, so raw materials needed cheaper
  • require only a low temperature and use their own enzymes- cost effective
  • can be GM to carry out synthetic reactions which they would not do naturally
• what are the disadvantages of using microorganisms for biotechnology?

  • if conditions aren't ideal, the microorganisms don't grow properly or work efficiently
  • conditions required for microorganisms to work in could allow harmful microorganisms that cause food to go off/disease, so conditions have to be sterile
  • ethical issues with the use of GM microorganisms
• state and describe the roles of yeast and bacteria in producing foods

  • yeast- formation of ethanol for alcohol (brewing)
  • yeast- making of bread/to make bread rise (baking)
  • bacteria- cheese making
  • bacteria- yogurt making
• describe the processes involved in the production of ethanol and making bread rise

  yeast is required for these processes

  BAKING:

  • yeast mixed with water and sugar to respire aerobically
  • the carbon dioxide produced makes the bread rise
  • yeast rises in warm environment
  • cooked in hot oven where CO2 bubbles expand
  • yeast cells are killed by cooking

  BREWING:

  • Yeast respires anaerobically to produce ethanol
  • GM yeast ferment at lower and cheaper temperatures
  • enzymes in yeast
  • enzymes break down starch
  • sterilisation
  • fermentation- aerobic respiration of yeast
  • filtered and pasteurised
• describe the processes involved in cheese and yogurt making

  bacteria is required for these processes

  CHEESE-MAKING:

  • bacteria feed on lactose in milk and make milk go off
  • milk pasteurised and homogenised- fat droplets distributed evenly through milk
  • bacteria- turns into liquid whey
  • curds pressed
  • curds left to dry and mature

  YOUGURT MAKING:

  • pasteurisation and homogenisation of milk
  • fermentation with bacteria
  • mixed with sterilised fruit
• what are the advantages of using microorganisms to produce human food?

  • microorganisms reproduce fast and produce food faster than plants/animals
  • can use waste materials, reducing cost
  • can be GM to produce required protein
  • production of microorganisms not dependent on weather eg- breeding cycles
• what are the disadvantages of using microorganisms to produce human food?

  • requires sterile conditions which can add to costs
  • ethical issues about eating GM food
  • little natural flavour- needs additives
  • microorganisms can produce toxins if conditions aren't optimum