Biology

• Fermentor


  Apparatus used in biotechnology to grow microorganisms and produce useful products
• Parts of a fermentor


  • Nutrient inlet
  • Water jacket
  • Sterilisation
  • Probe
  • Down streaming
• Nutrient inlet


  • Supplies glucose and amino acids for respiration and growth of microorganisms
• Water jacket


  • Maintains constant temperature to avoid denaturation of enzymes and killing of microorganisms
  • Removes heat generated by respiration of microorganisms
• Sterilisation


  • High temperature and pressure to avoid contamination with pathogenic microorganisms and competition for nutrients
• Probe


  • Monitors pH and temperature
• Down streaming


  • Filtration to remove waste products, toxins and microorganisms, then concentration and crystallisation to purify the product
• Yeast respire anaerobically to produce carbon dioxide, alcohol and biofuel
• Increasing glucose concentration in fermentor


  Slows down production of penicillin antibiotic
• Immobilised enzymes


  Enzymes trapped in beads or columns to allow reuse and protect from changes in temperature and pH
• Advantages of immobilised enzymes

  • No contamination of product
  • Enzyme can be reused
  • Enzyme is more thermostable and pH stable
  • Allows higher enzyme concentration for faster reactions
• Genetic engineering


  Changing the genetic material of an organism by taking a gene from one species and inserting it into another
• Genetic engineering process


  1. Cut gene from donor organism using restriction enzyme

  2. Isolate plasmid from bacteria and cut with same restriction enzyme

  3. Use ligase enzyme to insert gene into plasmid, forming recombinant DNA

  4. Insert recombinant DNA back into bacteria

  5. Culture bacteria to allow growth and reproduction

  6. Culture genetically engineered bacteria in fermentor for large-scale production
• Why use same restriction enzyme


  • To leave complementary sticky ends for easy insertion of gene into plasmid
• Requirements for recombinant DNA technology

  • Specific restriction and ligase enzymes
  • Vector (plasmid) to carry gene
  • Culture of bacteria
• Advantages of recombinant DNA technology

  • Large quantities can be produced
  • Product is very pure
  • Process can be easily turned on and off
• Reasons for using bacteria in genetic engineering

  • No ethical concerns
  • Small and easy to grow
  • Reproduce quickly
  • Share same genetic material (DNA)
  • Have plasmids that can act as gene vectors
• Advantages of genetically modified crops

  • Resistant to herbicides
  • Resistant to pests/insects
  • Resistant to pathogens/diseases
  • Resistant to drought
  • Increased nutrient content
  • Altered properties (e.g. crispier potatoes)
• Disadvantages of genetically modified crops

  • Different taste
  • Potential harm to humans
  • Ethically unacceptable
  • Potential for escape of bacteria and unpredictable consequences
  • Farmers have to buy new seeds each season
  • Potential for creating super-weeds
  • Companies may patent new organisms and refuse to share benefits