microbiology

• What do microorganisms include

  bacteria fungi protocists and viruses
• how do bacteria reproduce

  asexually by binary fission
• how many cells does the human body consist of

  one trillion
• how much bacteria does the human gut contain

  140 trillion bacteria
• what kingdom are bacteria in

  prokaryotae
• how are spherical bacteria named

  ___cocci
• how are rod shaped bacteria named

  ___bacilli
• name all structures in a bacterium

  slime capsule, cell membrane, mesosome, peptidoglycan cell wall, cytoplasm, plasmid, ribosome, flagellum, circular DNA
• what size are ribosomes in bacteria

  70S
• how else are bacteria classified

  based on grouping patterns
• grouping pattern of bacteria with staphy__


  bacteria in clusters
• grouping pattern of bacteria with strep__


  bacteria in chains
• define autotrophic


  synthesise cell constituents using CO2 as the carbon source
• define photoautotrophic


  either photosynthesis with chlorophyll as an e- donor or alternatives using sulphur or hydrogen gas as an e- donor
• how else can bacteria be distinguished from each other

  by their antigenic features
• describe the gram stain technique

  1. application of crystal violet(purple dye)
  2. application of grams iodine soln
  3. alcohol wash (decolourisation)- differential stage
  4. application of safranin (a counter stain)
• describe colour change of gram positive bacteria during gram stain technique


  1. purple
  2. light purple
  3. light purple
  4. light purple
• colour change of gram negative bacteria during gram stain technique


  1. purple
  2. light purple
  3. colourless
  4. red-pink
• does gram positive or gram negative bacterium cell wall contain lipopolysaccharide


  gram negative
• which bacteria has a more complex cell wall

  gram negative
• which cell wall retains crystal violet stain

  gram positive
• which bacteria has antibiotic susceptibility

  gram negative and positive
• example of gram positive

  streptococcus
• example of gram negative

  salmonella
• describe gram positive bacterial cell wall

  • no outer lipopolysaccharide
  • thick peptidoglycan cell wall
  • plasma membrane
• describe how gram positive bacteria stains

  gram Positive = Purple
• describe gram negative bacterial cell wall

  • outer lipopolysaccharide
  • thin peptidoglycan cell wall
  • plasma membrane
• what colour does gram negative bacteria change to

  red-pink
• which bacteria is not susceptible to some antibiotics

  gram negative - due to more complex cell wall
• how can unicellular yeast reproduce

  budding
• describe temperature conditions for bacterial growth

  bacterial metabolism = enzyme regulated

  • most bacteria thrive between 25 -45 degrees celcius
• optimum temperature for mammalian pathogenss

  37 degrees celcius
• how are nutrients supplied to bacteria in the laboratory

  supplied in nutrient media

  e.g

  • nutrient agar
  • liquid broth
• carbon source for bacteria on agar

  glucose
• nitrogen source for bacteria on agar

  amino acids
• how is nucleic acid synthesis provided on agar

  nitrate ions
• what ph do bacteria favour

  slightly alkaline conditions
• what ph do most fungi thrive in

  slightly acidic environments
• define obligate aerobes


  can only survive and metabolise in the presence of oxygen

  • cannot survive without oxygen
• define obligate anaerobes


  can only survive and metabolise in the absence of oxygen