micro ch 5

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micro ch 5
2010-07-09 12:55:18

micro ch 5
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  1. How do eukaryotic cells (amoeba) differ from prokaryotic cells (bacteria) in terms of growth and nutrition?
    • eukaryotes - get nutrients from absorption, ingestion, transport
    • prokaryotes - don't really get bigger; split; go from 1 to 2
  2. What are the inorganic nutrients bacteria need? Organic?
    • inorganic - metals, salts, gases, water
    • organic - proteins, carbs, lipids
  3. What are the two categories of bacteria in terms of how they obtain carbon?
    • autotrophs - CO2 (made by themselves)
    • heterotrophs - proteins, carbs, lipids (get from others)
  4. What is the energy source for photoautotrophs and photoheterotrophs?
  5. Macronutrients play principle roles in what? They are required in what quanitites? Examples?
    cell structure & metabolism; required in large quantities (ex = proteins & carbs)
  6. Micronutrients/trace elements play principle roles in what? They are required in what quanitites? Examples?
    enzyme function & maintaining protein structure; required in small amounts (ex = manganese, zinc, nickel)
  7. Putting a bacteria from optimum to cold does what?
    You don't kill bacteria, just stop it from growing (slows it down)
  8. What do phychrophiles have that make them resistant to freezing?
    certain proteins and are genetically made
  9. What is the conversion of hydrogen sulfide into food?
  10. The bacteria in your stomach live in a pH of 0.5. What do they do to survive?
    Take attributes from the urea & make ammonia (basic).
  11. In the heat vents miles below the water surface, bacteria live as symbiotes in _____.
    tube worms (tube worms have no digestive system)
  12. What happens to our proteins at extreme heat?
    They are denatured
  13. How do microbes eat radioactivity?
    • Rock contains radioactive elements that break down into water.
    • H2O2 is made.
    • H2O2 reacts with FeS2 to make SO4.
    • MIcrobes eat the SO4.
  14. The ____ pressure of an organism can change with the addition of salts or sugars.
  15. Where would you find high O2 tension/obligate aerobes?
    blood, lung, kidney
  16. Where would you find low O2 tension /obligate anaerobes?
  17. Tissue cut during trauma becomes anaerobic or aerobic?
  18. What is the increase in bacterial numbers due to binary division?
    bacterial growth (growth exponentially)
  19. What is the term for the time for a cell population to double? (1 to 2)
    Generation Time
  20. What happens in the lag phase of growth?
    • getting started
    • lasts about 5 hours
    • cells increase in size
    • no cell division
    • increase in metabolic activity
    • synthesis of cell compenents
  21. What happens in the log phase (exponential phase) of growth?
    • cells dividing at a constant, exponential max rate
    • lasts about 10 hours (E. coli = 20 min)
    • rate determined by species and temp
  22. What is the stationary phase of growth?
    • plateau
    • stop dividing (run out of nutrients, too many waste products, etc)
    • decreased growth rate (some are dying, some are growing)
    • viable cell count remains the same
  23. What happens in the death phase of growth?
    the number of dying exceeds the number of new cells formed
  24. What is in vitro vs. in vivo?
    • in vitro = in a test tube
    • in vivo = in the body
  25. The organism must be treated before it reaches the ____ phase, or else growth of the organism will be so fast that the host cannot keep up with the infection.
  26. cells that are not growing are not ___ to disinfectants and antimicrobials.
  27. What is acute vs. chronic infection? Examples?
    • Acute:
    • - rapid onset
    • - ex = strep throat and e coli (20 minutes)
    • Chronic:
    • - take months before recognized
    • - slow generation (12 hours)
    • - ex = TB
  28. How long does it take for antibody production?
    7 days
  29. A ____ amount of bacteria is often needed to show symptoms, but even one bacterium can cause disease.
  30. What is the role of anoxic sediments in the environment.
    • Harbors archaea that produce methane.
    • Methane rises to top and is given to the bacteria in that zone.
    • Methane can be a source of carbon.
  31. Bacteria are key in the cycling of ____ in ecosystems.
  32. What is a biofilm?
    bacterial community composed of microcolonies of bacteria surrounded by a gooey extracellular matrix that they secrete
  33. What is the signaling process of neighboring bacteria?
    quorum sensing (autoinducers)
  34. With exposure to bleach, the cells on the outside of the biofilm ___ while the cells inside ____.
    die; live
  35. Where can some biofilm infections be found?
    • implants
    • artificial joints
    • urinary cathetar
    • dental cavities
    • slimy contact lenses
    • right after surgery
  36. How does a biofilm overwhelm the immune system?
    the cells turn on toxin production all at once
  37. In relation to biofilms, how does cystic fibrosis work?
    • forms biofilm
    • neutrophils (immune system cells) and microphages can't come in
    • dispersal not uncommon
  38. What is a biofilm-forming bacteria?
  39. What are some ideal characteristics of disinfectants?
    • rapid action
    • maintained efficacy in presence of protein or blood
    • low toxicity
    • user safety (user friendly; not corrosive to hands, etc)
    • material combatibility
  40. What are the 3 microbial control methods?
    • physical agents
    • chemical agents
    • mechanical removal methods
  41. What is COMPLETE removal of all viable organisms?
  42. What is the hygiene hypothesis?
    not letting us build immunities because we are too obsessed with cleanliness
  43. what is a sterilizing gas used in an autoclave?
    ethylene oxide
  44. What are some of the factors relating to the control of microbial organisms?
    • effect of initial load of microbes
    • number of microbes (the more there are, the longer it takes to kill them off)
    • microbial characteristics
    • environmental influence/presence of organic matter (fats & proteins protect; heat is more effective with low pH)
    • time of exposure (spores longer than vegetative cells)
  45. an autoclave can kill vegetative cells and spores within ___ minutes; they are used to clean ____
    15 minutes; solutions, dressings, equipment (medical--can't have plastic or rubber)
  46. an autoclave must occur within a ____
  47. What is the removal of water (i.e. instant coffee)
  48. what are forms of dry heat when it comes to controlling microbes?
    burner/incinerator (120C for more than 2 hrs)
  49. what contributes to bacteriostatic effects & decreased chemical reactions
    cold - refrigeration
  50. What is radiation?
    the destruction of DNA
  51. what does this symbol represent?
    cold pasteurization = irradiated food (ionizing radiation)
  52. What does ionizing radiation use?
    gamma rays and high energy electron beam
  53. What does non-ionizing UV entail?
    produced by electric currents passing through special lamps (for air and surfaces)
  54. What is a major problem with radiation?
    you kill EVERYTHING and medial/radiation waste
  55. Iodine and chloride are what?
  56. What does bleach do to enzymes and proteins?
    unfolds them
  57. What does hypochlorous acid do to proteins in the cell membrane?
    oxidize them
  58. How do you make a 10% bleach solution?
    1 part HClO and 9 parts H2O
  59. What are the most resistant microbes? the least?
    • most - prions, spores
    • least - viruses with lipid envelopes, gram + bacteria
  60. what is harder to kill, gram pos or gram neg bacteria?
    gram neg (because of the outer membrane)
  61. What are some primary protection barriers?
    • hoods (air flows up and out)
    • masks
    • gloves
    • gowns
    • booties
    • breathing apparatus
    • special showers
  62. what are some examples of inorganic nutrients?
    • metals and their salts (magnesium sulfate, ferric nitrate, sodium phosphate
    • gases (oxygen, CO2)
    • water
  63. What are some examples of organic nutrients?
    methane (CH4), carbs, lipids, proteins, nucleic acids
  64. Where in the body are there aerobic conditions? (high oxygen tension)
    blood, lungs, brain, kidney, bone
  65. Where in the body are there anaerobic conditions? (low oxygen tension)
    intestines, clostridium (lives in intestinal tract, causes C diff)
  66. what can make an anaerobic condition?
    • narrowing of blood vessels
    • trauma (breaking cap beds)
    • surgery