Microbiology

• Virus

  • Bacteriophage - viruses that infect bacterial cells
  • Bacteriophages have a head, sheath and tail.
  • Contain DNA or RNA (never both)
  • Are acellular (no nucleus or organelles)
  • Only characteristic of life is reproduction, but can only reproduce in a host.
  • Some are host specific and others are tissue specific.
  • Reproduce by converting genetic material of the host into viral nucleic acids
• Bacteria

  • Kingdom Monera
  • Smallest and simplest living organisms
  • Prokaryotic(no nuclear membrane/no true nucleus)
  • DNA is free in cytoplasm
  • Aerobic bacteria - live in presence of O2
  • Anaerobic bacteria - live in absence of O2
  • DNA is concentrated in a Nucleoid.
  • Tail = flagella
  • Some are autotrophic( can photosynthesise or chemosynthesise) Asexual reproduction via binary fission
• Protista

  • Kingdom Protista
  • Protozoa, Algae & Water mould
  • Uni or multicellular
  • Eukaryotic
  • Algae is the only autotrophic protista
  • Reproduce both asexually & sexually Protozoa ingest food by phagocytosis. Cell walls occur in plant-like protists(Algae). Some algae sexual and others asexual reproduction.
• Binary fission

  Asexual reproduction
• Fungi

  • Kingdom Fungi
  • Yeasts are unicellular
  • Mushrooms and moulds are multicellular
  • Eukaryotic
  • Heterotrophic
  • Saprophytes(live off of dead organisms)
  • Asexual(binary fission) and sexual reproduction
  • Some are parasites
• Nitrogen fixing bacteria

  • Bacteria absorbs nitrogen gas in soil and convert it into nitrates so that plants can absorb it.
  • In exchange, bacteria receive carbohydrates from the plants.
  • Both plants benefit from this symbiosis
• O2/CO2 homeostasis

  • Autotrophic bacteria and protists use CO2 and release O2
  • Algae are responsible for 50% of O2 that is produced by photosynthesising organisms.
• Conditions for growth & multiplication


  • Sufficient food
  • Moisture
  • Optimal temperature
• Pathogens


  Microorganisms that cause disease
• Infectious Disease 


  Diseases caused by a microorganism
• Microorganisms 


  Living organisms that cannot be seen by the naked eye.
• Fungi Fungi

  • Kingdom Fungi

  Macroscopic Fungi

  • Fleshy fungi with visible fruity bodies(mushroom)

  Microscopic Fungi

  • Unicellular yeasts
  • Multicellular moulds & mushrooms
  • Eukaryotic organisms
  • Have cell walls
  • Heterotrophic
  • Saprophytes(Moulds & Mushrooms)
  • Parasitic (athletes foot)
  • Unicellular fungi - asexually via binary fission.
  • Multicellular - both sexually & asexually.