Biotechnology and genetic modification

• Microorganisms


  Can be used by humans to produce foods and other useful substances
• Bacteria


  • The most common type of microorganisms used in biotechnology
  • Capable of producing complex molecules
  • Reproduce rapidly, meaning the amount of chemicals they can produce can also rapidly increase
• Bacteria in biotechnology


  • Few ethical considerations to growing them in large numbers in the laboratory
  • Possess plasmids - small, circular loops of DNA which can be an ideal way of transferring DNA from one cell to another during genetic manipulation
• Anaerobic respiration in yeast

  1. Glucose

  2. Ethanol + Carbon dioxide
• Biofuel


  Fuel made from living organisms rather than a fossil fuel like oil, coal or gas
• Biofuel production


  • In Brazil, biofuel is partly replacing petrol as the fuel for cars and other vehicles
  • Plant material is used as the substrate for producing ethanol (as a source of glucose)
  • The liquid is separated from the remaining solids and any water is removed, leaving a concentrated solution of ethanol
• Biofuel production


  Causing concern that there is less land available for local people to grow food crops needed for survival
• Anaerobic respiration in yeast for bread making

  1. Glucose

  2. Ethanol + Carbon dioxide

  3. The carbon dioxide produced makes bread dough rise
• Pectinase


  Enzyme that breaks down pectin, a chemical found inside plant cell walls, allowing more juice to be released from fruit
• Biological washing powders


  • Contain enzymes similar to digestive enzymes that help to break down large, insoluble organic molecules like fats and proteins into smaller, soluble ones that will dissolve in washing water
  • Effective at lower temperatures, meaning less energy has to be used
  • Can be used to clean delicate fabrics that would not be suitable for washing at high temperatures
• Human babies are born with the ability to produce lactase, the enzyme that breaks down lactose
• Many people lose the ability to produce lactase as they get older, becoming lactose intolerant
• Lactose-free milk


  Made by adding the enzyme lactase to milk and leaving it to stand to allow the enzyme to break down the lactose
• LACTO


  Relating to milk
• FREE


  Not containing
• MILK


  A white liquid produced by the mammary glands of female mammals for feeding their young
• GLUCOSE


  A simple sugar
• LACTOSE


  A disaccharide sugar found in milk
• LACTASE


  An enzyme that breaks down lactose
• GALACTOSE


  A monosaccharide sugar that is one of the components of lactose
• Lactose-free milk


  A product made from adding the enzyme lactase to dairy milk to break down the sugars in it
• Penicillin


  The first antibiotic, discovered in 1928 by Alexander Fleming
• Penicillin Production


  1. Alexander Fleming noticed that some bacteria he had left in a Petri dish had been killed by the naturally occurring Penicillium mould

  2. The penicillium mould produces a chemical to prevent it being infected by certain types of bacteria

  3. The chemical was isolated and named penicillin

  4. Methods have been developed to produce it on a large scale, using an industrial fermenter
• Penicillin


  An antibiotic that interferes with the building of the bacterial cell wall
• Penicillin produced by the fungus Penicillium


  Inhibits bacterial growth
• Industrial fermenter


  • Containers used to grow ('culture') microorganisms like bacteria and fungi in large amounts
  • Conditions can be carefully controlled to produce large quantities of exactly the right type of microorganism
• Conditions controlled in a fermenter

  • Aseptic precautions
  • Nutrients
  • Optimum temperature
  • Optimum pH
  • Oxygenation
  • Agitation
  • Waste
• Mycoprotein


  A protein-rich food suitable for vegetarians, produced from the fungus Fusarium
• Mycoprotein production


  1. The fungus Fusarium is cultured (grown) on an industrial scale in fermenters

  2. The fungus is grown in aerobic conditions and provided with glucose syrup as a food source

  3. The fungal biomass is then harvested and purified to produce mycoprotein
• Genetic modification


  Changing the genetic material of an organism by removing, changing or inserting individual genes from another organism
• Transgenic organism


  An organism that has received genetic material from another organism
• Recombinant DNA


  The DNA of an organism that now contains DNA from another organism as well
• Genetically modified organisms


  • Bacteria producing human insulin
  • Crop plants resistant to insect pests or herbicides
  • Crop plants producing additional vitamins
• Genetic modification using bacterial production of a human protein

  1. The gene that is to be inserted is located in the original organism

  2. Restriction enzymes are used to isolate the required gene, leaving it with 'sticky ends'

  3. A bacterial plasmid is cut by the same restriction enzyme leaving it with corresponding sticky ends
• DNA


  Double stranded
• Restriction enzyme


  • Cuts DNA strands at specific sequences
  • Forms 'sticky ends'
• Genetic engineering process


  1. Plasmid and isolated gene joined together by DNA ligase enzyme

  2. Recombinant plasmid inserted into bacterial cell

  3. Bacteria reproduce, copying plasmids

  4. Recombinant plasmid spread as bacteria multiply

  5. Bacteria express gene and make human protein
• Bacteria


  • Contain same genetic code as organisms genes taken from
  • No ethical concerns over manipulation and growth
  • Presence of plasmids separate from main chromosome makes them easy to remove and manipulate
• Advantages of GM crops

  • Reduced use of chemicals like herbicides and pesticides - better for environment
  • Increased yields from crops not competing with weeds or suffering pest damage
  • Cheaper/less time-consuming for farmers
• Disadvantages of GM crops

  • Increased costs of seeds - companies charge more to cover development costs
  • Increased dependency on certain chemicals like herbicides crops are resistant to
  • Risk of inserted genes transferring to wild plants, reducing usefulness of GM crop
  • Reduced biodiversity as fewer plant species when herbicides used
  • Some research shows GM plants don't grow as well as non-GM plants