section 9 - use of biological resources

• Ways to increase yield of crops


  • Increase photosynthesis (use polytunnel or greenhouse)
  • Use fertilisers
  • Pesticides
• Organic fertilisers


  Manure and straw, bad as can't control composition
• Inorganic fertilisers


  Potassium, phosphorus, nitrates and ammonia, bad as cause eutrophication
• Too many seeds/plants


  Negative effect due to increased competition for O2, yield is reduced
• Pests


  Animals, plants, bacteria, virus and fungi
• Biotechnology


  Using microorganisms to make food, e.g. yoghurt and bread
• Fermentation


  How microorganisms make energy
• Process of a fermenter used to make yeast cells


  1. Supply oxygen for aerobic respiration and remove it for anaerobic respiration

  2. Air filter and sterilisation removes microorganism contamination

  3. Glucose is provided for respiration

  4. Stir to distribute heat and cooling to control temperature
• Conditions monitored in fish farming


  • Predation: intraspecific (separate fish by size) and interspecific (separate with nets)
  • Disease: pesticides, biological controls and antibiotics (good because prevent disease and increase fish yield, bad because antibiotic resistance in fish and humans)
  • Diet: fed pellets (high protein for growth, made of wild fish and contain antibiotics)
  • Water quality: control pH, temperature and oxygen
  • Breeding: selective breeding
• Selective breeding - Animals


  • Higher yield, more offspring, better quality fur, resistant to disease and pests, run faster, mature faster
• Selective breeding - Plants


  • Higher yield, resistant to disease and pests, more nutritious/flavour/longer shelf life
• Selective breeding - Animals


  1. Select organism with desired characteristic

  2. Bred together

  3. Offspring that have the desired characteristics, bred together for many generations
• Selective breeding - Plants


  1. Select organism with desired characteristic

  2. Bred together

  3. Seeds are collected and germinated

  4. Offspring that have the desired characteristics, bred together for many generations
• Genetic engineering


  Taking gene from one organism and transfer to another
• Genetic engineering to make insulin


  1. Remove plasmid

  2. Cut gene using restriction enzymes

  3. DNA ligase stick to form recombinant DNA in transgenic organism (bacterium)

  4. Bacterium makes insulin
• Genetic engineering in crops


  • Benefits: resistant to disease/pests, increase nutrition value, increase yield

  Negatives: Could affect food chains/human health/long-term effects
• Cloning


  Making identical copies by asexual reproduction using mitosis
• Cloning - Plants


  • Benefits: Large quantity quickly, Can grow all year, Can grow endangered to increase

  Negatives: Identical offspring so vulnerable to disease, Need sterile lab, Vulnerable to pests
• Cloning - Animals


  • Benefits: Large quantity quickly, Can grow all year, Can grow endangered to increase

  Negatives: Identical offspring so vulnerable to disease, Need sterile lab, Vulnerable to pests
• Cloning process


  1. Nucleus from one is put into enucleated egg cell of other

  2. Using electricity egg cell is stimulated to divide (by mitosis) into embryo

  3. Embryo is implanted into uterus of a surrogate