Medical Microbiology

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Medical Microbiology
2011-02-24 22:11:27

things i need to know for the second exam based on bacteria
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  1. cell division
    • binary fission
    • budding
    • mitosis
    • meiosis

    (incomplete seperation is what leads to diplo, tetra, palisade, etc.)
  2. Lag Phase
    (bacterial population growth curve)

    individual cells are growing but haven't divided yet
  3. Log Phase
    (bacterial population growth curve)

    Cells growing exponentially
  4. Stationary phase
    (bacterial population growth curve)

    dying as fast as they are dividing
  5. Decline/Death phase
    (bacterial population growth curve)

    • -pH changes from waste of dying bacteria
    • -no cells are divinging anymore
  6. Medium:
    solid - complex of CHO from marine algae

    • plates: ideal for isolating cultures
    • Stabs: find out if the bacterium is motile
    • Slants: (if lucky) can isolate individual colonies
  7. Medium:
    • liquid
    • bacteria grows quickly
    • shows different patterns of arrangement from plates
    • always define shape from broth because it would be the same every time
  8. Medium:
    soil, living or dead tissue
  9. Medium:
    synthetic - defined
    every batch identicle
  10. Medium:
    synthetic - undefined:
    • blood, beef extract
    • variations from sample to sample - but we know whats in it
  11. Medium:
    promotes growth of some but inhibits growth of others
  12. medium:
    color or medium change to let you know something is happening
  13. Medium:
    • fosters growth of bacteria - fastidious
    • ones that can't grow need something to help
  14. mannitol salt agar
    synthetic, selective, not enriched, differential between 2 staph species
  15. blood agar
    • synthetic
    • not selective. al bacteria grow
  16. pH:
    grows in acidic
  17. pH:
    grows in neutral conditions
  18. pH:
    grows in basic conditions
  19. temperature:
    grows in cold condition
  20. temperature:
    grows in moderate condition
  21. temperature:
    grows in ht conditions
  22. oxygen:
    obligate aerobes
    needs oxygen
  23. oxygen:
    small amount of oxygen
  24. oxygen:
    facultative anerobes
    with or without oxygen
  25. oxygen:
    aerotolerant anerobe
    doesn't need oxygen but can live with it
  26. Oxygen:
    obligate anerobes
    doesn't need oxygen
  27. Osmotic pressure
    • water follows salt.
    • needs to have water for metabolism
    • to high of a salt concentration outside water will leave bacterium
    • with no fluid cytoplasm - organelles can't move around
  28. Bias in culturing
    • most microbes can't be cultered
    • don't know what the culture needs
    • can't count them
  29. DNA replication
    • semi-conservativ
    • complementary base pairing (A--T & G---C)
    • process enzyme mediated
  30. Gene expression
    happens at all times (product = proteins)
  31. Feedback inhibition
    final product of protein synthesis inhibits the starting enzyme
  32. Enzyme induction
    protein makes promotor site on DNA more accessible
  33. Enzyme repression
    protein blocks transcription
  34. genetic variations
    gives a population the ability to survive when the enviroment changes
  35. Population:
    group of the same species living in the same area at the same time
  36. Biological species concept
    group of individuals that reproduce sexually with each other (and produces viable healthy offspring)
  37. Species (bacterial)
    • unique phenotypic properties
    • >70% DNA homology among strains
  38. Strain
    descendants of a single isolation in a pure culture
  39. Mutations
    • subsitution: nucleotide changes
    • deletion: nucleotide removed
    • insertion: nucleotide added
    • inversion: nucleotide flips and re-inserts itself
    • transposon
  40. effect of mutation:
    can't be transcribed
  41. effects of mutations:
    slight change
    • similar enzyme made
    • reaction slows
  42. effects of mutations:
    big change
    • different enzyme produced
    • or codon changed to stop codon
  43. effects of mutation:
    no change
    3 codons still make same enzyme
  44. Vertical gene transfer
    • sexually reproducing
    • binary fission
    • recombination
  45. horizontal gene transfer
    • asexually
    • transformation
    • transduction
    • conjugation
  46. transformation
    bacteria uptakes naked DNA from other bacteria so they then have the genes
  47. Transduction
    • DNA from bacteriophages
    • bacteriophages binds to cell based on surface enzymes
    • injects it's DNA
    • host cell makes more pieces and they're released
    • some may also contain bacterial DNA
  48. conjugation
    • closest to sexual reproduction
    • plasmids project receptors on their surface so they know which cells have the plasmid.
    • when they find a cell that doesn't have the plasmid they bind to each other and the plasmid injects a strain into the cell
    • a complimentary stad is made
    • each cell has a copy
  49. classification of bacteria
    • morphology and stains
    • growth characteristics/colony morphology
    • nutritional needs
    • biochemical tests
    • DNA sequencing
    • phage typing
    • rRNA sequencing