Microbiology

Microbiology

Fungi
1. Moulds, yeast & large fungi
2. Do not make their own food
3. Parasitic fungi feed on living matter - athlete's foot
4. Saprophytic fungi feed on dead matter - mushrooms on soil
5. Moulds
  1. Most are mesophiles - freezing inactivates growth
  2. Moisture is needed for growth
    1. Classification of moulds
      1. Phycomycetes
        Reproduce asexually & sexually
        Produce sporangium
        Thrives at 30 degrees
        E.g. Mucor & Rhizopus
        Saprophytic mould
        Reproduces asexually & sexually
        White hyphae
        Grows on bread & soil
        Saprophytic mould
        Reproduces asexually
        Fluffy white mycelium
        Grows on bread & vegetables
      2. Ascomycetes
        Reproduces asexually only
        Conidium develop from the hyphae
        Thrive at 20 -30 degrees
        E.g. Penicillium & Aspergillis
        Saprophytic mould - green/ blue
        Used in blue-veined cheeses & antibiotics
        Grows on cheese & bread
        Saprophytic mould - black
        Grows on fruit & vegetables
  3. Moulds are aerobic & need oxygen so they can grow on the surface of food
  4. pH levels - moulds grow in slightly acidic conditions
  5. Mould needs time to multiply
  6. Reproduction
    1. Sexually
      1. Two hyphae grow beside each other
        They fuse together
        The dividing wall breaks down & a zygospore develops
        Zygospore produces & stores spores
        It has a thick wall & protects the spores
        When conditions are suitable, the spores germinate & hyphae grow & extend out
        Spores are released into the air & the cycle begins again
    2. Asexually
      1. A hypha grows upwards
        The head of a hypha
        Round (sporangium)
        Chain of spores (condium)
        The head bursts & releases spores which travel into the air
        If a spore finds suitable conditions, new mould growth will begin
  7. Moulds are saprophytes & feed on dead organic matter
  8. Structure
    1. Multi-cellular fungi & can be seen on food
    2. Each mould begins as a spore
    3. Develops a thread-like filament called a hypha which grows down into the food
      1. Hypha grows out & branches into hyphae
        Hyphae intertwine & become a mycelium
Bacteria
1. Bacteria is classified by shape & gram staining
  1. Shape
    1. Rod (bacillus)
      1. Food poisoning - salmonella, listeria
    2. Spherical (cocci)
      1. Form
        Clusters: staphylococci - food poisoning
        Chains: streptococci - sore throat
    3. Spiral (spirilla)
      1. STD's - Syphilis
Micro-organisms
1. Secrete enzymes onto their food source
  1. These enzymes break down the food into simple compounds
    1. These simple compounds are absorbed through the cell wall & provide nourishment for growth
Terminology
1. Parasites
  1. Micro-organisms that feed on living matter - humans/animals
2. Saprophytes
  1. Micro-organisms that feed on dead organic matter - soil, food
3. Psychrophiles
  1. Micro-organisms that thrive at low temperatures between -5 to 20 degrees
4. Mesophiles
  1. Micro-organisms that thrive at temperatures between 20 - 45 degrees
5. Thermophiles
  1. Micro-organisms that thrive at temperatures between 45 - 75 degrees
6. Aerobic
  1. Micro-organisms that need oxygen
7. Pathogens
  1. Bacteria that cause diseases

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