Microorganisms

• Enzyme


  A biological catalyst
• Role of enzyme in digestion


  Catalyses chemical reactions in the body
• Small intestine absorption


  • Highly folded to increase surface area
  • One cell thick to reduce distance for absorption
  • Network of blood capillaries to maintain steep concentration gradient
• Main types of microorganisms

  • Bacteria
  • Fungi
  • Virus
• Bacteria


  • Size: 0.2-2 μm
  • Living: yes
  • Reproduction: binary fission
  • Examples: coccus, bacillus, vibrio
• Fungi


  • Size: 2-10 μm
  • Living: yes
  • Reproduction: forms fruiting bodies that release spores
  • Examples: yeast, mushrooms, mold
• Virus


  • Size: 20-400 nm
  • Living: no
  • Reproduction: attach and enter into a cell, then replicate themselves in the cell, then assemble, and then release all the viruses that were created into the body and the process repeats
  • Examples: COVID, the flu, HIV
• Aseptic technique for culturing microorganisms

  1. Get a petri dish and cover the bottom in agar without letting it touch the air

  2. Take a disinfected cotton bud and swab the area you want to test

  3. Open the petri dish to the very minimum and gently swab the cotton bud onto the petri dish, careful not to break the agar

  4. Close the lid and tape it together

  5. Store in an incubator upside down
• Pathogen


  A microorganism that causes disease
• How pathogens spread


  • Direct contact
  • Airborne
  • Insects
  • Dogs
  • Contaminated food
  • Water
  • Body fluids
• Types of medicine

  • Aspirin
  • Digoxin
  • Antidepressants
  • Morphine
  • Antibiotics
• Aspirin

  Treats headaches, toothaches, brings down temperatures for colds + flu-like symptoms, comes from willow bark (now officially synthesised)
• Digoxin

  Treats heart failure, comes from foxglove plant
• Antidepressants


  Treat OCD, PTSD + depression, come from saffron, tumeric, st john's wort
• Morphine

  Treats severe pain, comes from drying latex of opium poppies
• Antibiotics


  Treat bacterial infections, come from soil bacteria + fungi
• How antibiotics treat bacterial infections

  They cause ruptures in the bacteria cell wall which means that when they try to expand and reproduce, they burst and die
• Methods of preserving food

  • Pickling
  • Curing (salting/drying)
  • Freezing
  • Pasteurizing
  • Cooking
  • Canning
  • Oiling
• How pickling works

  Acidity kills microbes on the food and no new ones can survive, acidity de-natures the microbes enzymes
• How curing works


  Dehydrates the food + microbes on it, works because microbes need water/moisture to grow and thrive
• How freezing/chilling works


  Cold temperatures slow down microbes reactions in their cells which makes them grow and reproduce at a very slow rate
• How pasteurizing works


  Uses high heat and pressure to denature enzymes and kill the microbes so they cannot grow
• How cooking works


  Denatures the enzymes, microbes cannot survive under such high heat and are therefore removed from the food
• How canning works


  Microbes are killed using the heat and then are sealed in a can, no oxygen and therefore microbes cannot survive
• How oiling works


  Oxygen cannot dissolve in oil very easily, no oxygen means microbes cannot survive