Microbiology Exam 2

  1. The complete elimination of all lifeforms, including endospores.
  2. Does sterilization include endospores?
  3. The elimination of all vegetative cells of pathogens.
  4. Are all cells killed during disinfection? If not, what is left?
    No, non-pathogenic cells may be present.
  5. The reduction of pathogens to a "safe" level.
  6. Sterilization uses what? Disinfection uses what? Sanitization uses what?
    • Sterilants
    • Disinfectants
    • Sanitizers
  7. Disinfectants that have been approved for use on the body.
  8. The specific way the method accomplishes killing or inhibition.
    Mechanism of Action
  9. What are the three most common mechanisms of action?
    • Damage to proteins and DNA
    • Altering of membrane permeability
    • Slowing down metabolism
  10. What methods work by damaging proteins and DNA?
    • Wet Heat (denatures proteins)
    • Heavy Metals (interfere with protein function)
    • Radiation (damages DNA)
  11. Damage to cell membrane causes the membrane to become what? What could this lead to?
    Leaky, loss of nutrients or permits entry of undesirable substances
  12. What mechanisms of action work by altering the permeability of cell membranes? How do they work?
    • Phenolics
    • Quarternary Ammonium Compounds
    • They insert themselves into the cell membrane and cause holes
  13. What mechanisms of action work to slow down metabolism?
    • Cold
    • Desiccation
  14. Cold and Dessication are what kind of methods?
  15. The difference in Bacteriostatic and Bacteriocidal?
    • Bacteriostatic: slow down metabolism and stop reproduction of bacteria
    • Bacteriocidal: kill bacteria
  16. Methods of Control can be what?
    Physical or Chemical
  17. How do Physical methods of control work?
    Alter the physical environment.
  18. What are some examples of Physical methods of control?
    • Heat/Cold
    • Radiation
    • Desiccation/Osmotic Pressure
    • Filtration
    • Soaps/Detergents
  19. What are some Chemical methods of control?
    • Phenolics
    • Halogens
    • Alcohols
    • Heavy Metals
    • Aldehydes
    • Quaternary Ammonium Compounds
    • Peroxides
  20. What mechanism of action is used by Moist Heat?
    Denatures protein.
  21. What is an example of Moist Heat?
    Hot Water or Steam
  22. What are some ways to use Moist Heat?
    Boiling, Autoclaving, or Pasteurization
  23. Do endospores survive boiling? Definitely under what time?
    Usually yes, especially if boiling for under ten minutes
  24. How do Autoclaves work?
    They use steam under pressure.
  25. What is the most common temperature and time used in Autoclaving?
    121 degrees Celsius for 15 minutes (or 15psi).
  26. What is the target organism for the pasteurization of milk?
    Coxiella burnetii
  27. What does Coxiella burnetti cause?
    Q Fever
  28. What are commercial canners called? What is their process called?
    Retorts, commercial sterilization
  29. What is the target organism for commercial canning?
    Endospores of Clostridium botulinum
  30. What is the most common case of botulism caused from?
    Inadequately processed home canned foods.
  31. What time and temperature should home canners be used at?
    121 degrees Celsius for 15 minutes (or 15psi)
  32. What is the mechanism of action for Dry Heat?
    Kills by burning.
  33. What is an example of Dry Heat?
    Fire or Hot Air
  34. What is a way to use Dry Heat?
  35. Is Dry Heat more or less effective than Moist Heat at the same temperature?
    Less effective.
  36. What is the most common time and temperature used to sterilize with hot air?
    160 degrees Celsius for 120 minutes
  37. What objects are Dry Heat usually used on?
    Glass or Metal, due to high temperatures
  38. What happens to carcasses of cattle infected with anthrax?
    They are often incinerated to make sure the endospores are destroyed.
  39. What is anthrax caused by?
    Bacillus anthracis
  40. Flaming the loops in lab is an example of what method?
    Dry Heat
  41. What is the mechanism of action for Cold?
    Slows metabolism.
  42. What is a way we use Cold?
    Freezing or Refrigeration
  43. Cold temperatures are bacterio-static/cidal?
  44. What is the growth of mesophiles inhibited by? What is the exception?
    Refrigeration temperatures. Listeria monocytogenes.
  45. Where do psychrotrophs grow? What are they responsible for?
    Refrigeration temperatures. Refrigerated food spoilage.
  46. What is the most common spoiler of raw meats?
    Pseudomonas fragi
  47. What is the mechanism of action for Radiation?
    Damages DNA
  48. What is an example of Radiation?
    Ionizing and Non-Ionizing
  49. What rays are ionizing?
    • Gamma Rays
    • X-Rays
    • Electron Beams
  50. What rays are Non-Ionizing?
  51. Ionizing Radiation is energetic enough to do what?
    Knock electrons off of atoms.
  52. What are Gamma-Rays and X-Rays used for?
    Sterilizing goods after packaging.
  53. What is the most commonly used source of Gamma Rays?
  54. What is UV Radiation useful for?
    Surface and Air Treatment
  55. Hospitals may have what kind of rays?
    UV, to disinfect the air
  56. What is the most effective wavelength of light? Why?
    260 nanometers, DNA absorbs UV Rays best at that wavelength
  57. UV light causes what?
    Thymine Dimers
  58. The biological hood in the lab contains what type of Radiation?
    UV Light
  59. What is the mechanism of action for Dessication?
    Slows metabolism
  60. What is something Dessication does?
    Drying or Dehydrating Food
  61. Is Dessication Bacterio-static/cidal?
  62. Why does Dessication work?
    All organisms require water, when moisture becomes too low enzymes no longer function
  63. Foods with less than what percent of water content inhibit all bacterial growth?
  64. Do Fungi or Bacteria tolerate low water levels best?
  65. Where would molds more likely grow than bacteria?
    Cheese and Bread
  66. What is the mechanism of action for Osmotic Pressure?
    Draws water out of cells and causes plasmolysis
  67. What is something that causes Osmotic Pressure?
    High levels of salt or sugar in moist foods
  68. What are some foods where Osmotic Pressure is common?
    Jellies, Jams, Honey, Syrup, Salted Meat
  69. What pathogen may salty foods still be vulnerable to?
    Staphylococcus aureus
  70. Staphylococcus aureus grows in water salt concentration?
    More than 7%
  71. What is the mechanism of action for filtration?
    Removes microbes.
  72. Where is filtration used?
    Operating Rooms, Safety Hoods, Membrane Filters
  73. What filters are used to filter air?
    HEPA (high-efficiency particulate air filters)
  74. HEPA filters capture a minimum of what percent and size of particles that pass through the filter?
    99.97% of 0.3micrometers
  75. Most bacteria are what size?
    More than 1 micrometer
  76. What are membrane filters used for?
    To filter fluid.
  77. What is the common size of a membrane filter pore?
    0.45 micrometer
  78. What is the mechanism of action of Soaps and Detergents?
    Decrease surface tension.
  79. What does increased surface tension allow for bacteria?
    To be lifted and carried off.
  80. How much germicidal action do Soaps and Detergents have?
    Little or No action.
  81. What do Soaps and Detergents do to microbes?
    Rather than kill, they make it easier for rubbing and rinsing to carry away any microbes on a surface
  82. To be able to put "antimicrobial" on a level, one must first do what?
    Make sure the product meets government regulations.
  83. Antimicrobial products are regulated by who?
    FDA (Food and Drug Administration)
  84. The EPA calls Antimicrobials what? The FDA calls them what?
    Pesticides, Drugs
  85. What microbes are most resistant to chemicals?
    Endospores and Mycobacteria
  86. Why are endospores and mycobacteria most resistant to chemicals?
    Their waxy mycolic acid coat.
  87. Eukaryotic organisms are generally more/less resistant to chemicals?
  88. Bacteria are most resistant to chemicals than what?
  89. Among gram-negative bacteria, what species is particularly resistant to chemicals? Why?
    Psuedomonas, their porins are more selective about what they let through
  90. List major groups of microorganisms from MOST resistant to LEAST resistant to chemicals.
    • Endospores
    • Mycobacteria
    • Cysts of Protozoa
    • Vegetative Protozoa
    • Gram-Negative Bateria
    • Fungi (including spores)
    • Non-Enveloped Viruses
    • Gram-Positive Bacteria
    • Enveloped Viruses
  91. What are most viruses surrounded by?
    A membrane called an envelope.
  92. What is the mechanism of action for Phenolics?
    Disrupt cell membranes.
  93. What is an example of a Phenolic?
    Thymol, Triclosan
  94. What are Phenolics effective against?
  95. What is Thymol an active ingredient in?
  96. What is Triclosan an active ingredent in?
    "Antibacterial" liquid handsoaps and detergents.
  97. What is the mechanism of action of Halogens?
    Inhibit proteins.
  98. What are some examples of Halogens?
    Fluoride, Chlorine, Hypochlorite (HOCl), Iodine, Iodophors
  99. What is Fluoride used in?
    Toothpaste (1000ppm)
  100. What is Chlorine used for?
    To treat drinking water.
  101. What is Hypochlorite an active ingredient in?
    Bleach (5%)
  102. What is Iodine used for?
    Prepping the skin before an injection.
  103. What are Iodophors?
    Iodine combined with detergent.
  104. What are Iodophors used for?
    Prepping areas before surgery.
  105. What is Alcohol's mechanism of action?
    Inhibit proteins, dissolve lipids
  106. What is an example of Alcohol?
    Ethanol, Isopropanol
  107. What is Isopropanol useful for?
    Household disinfectant.
  108. What is Ethanol often used for? Where do we also use it?
    Injection prep, lab to soak metal spatulas
  109. What is the most effective concentration of Ethanol or Isopropanol? Why?
    70%, some water is needed to denature the proteins
  110. What is the mechanism of actin for Heavy Metals?
    Inhibit Proteins
  111. What is an example of a Heavy Metal?
    Silver, Copper
  112. What was put onto the eyes of newborns? Why?
    Drops of 1% Silver Nitrate, to prevent the organism Neisseria gonorroheae infections, passed from mother during birth
  113. What is used for newborns today? To prevent what?
    The antibiotic erythromycin, Chlamydia trachomatis eye infections
  114. What has copper sulfate been used for?
    Treat swimming pools and prevent algal growth, and on grapes to prevent fungal growth
  115. What is the mechanism of action for Aldehydes?
    Inhibit Proteins.
  116. What is an example of an Aldehyde?
  117. Aldehyde is a potential what? Why?
    Sterilant because it is effective against endospores, Carcinogen
  118. What is the most effective group of disinfectants? Why aren't they used often?
    Aldehydes, suspected carcinogens
  119. Embalming solutions contain how much formaldehyde?
  120. Quarternary Ammonium Compounds have what mechanism of action?
    Disrupt cell membranes.
  121. What is an example of a quat?
    Benzalkonium chloride
  122. What is benzalkonium chloride usually listed as on labels?
    Alkyl Dimethyl Benzyl Ammonium Chloride
  123. Are Quats toxic/non-toxic? This allows them to be used where?
    Non-toxic, sensitive areas like eyewash solutions
  124. Quats are active ingredients in what?
    Lysol, Fantastik, household sanitizers
  125. Peroxides use what mechanism of action?
    Cause various oxidation reactions
  126. What is an example of a Peroxide?
    H2O2, benzoyl peroxide
  127. What peroxide is a household disinfectant?
    Hydrogren Peroxide
  128. What peroxide is common in topical acne medication?
    Benzoyl Peroxide
  129. What are the chromosomes of bacteria like?
    Singular, Circular
Card Set
Microbiology Exam 2
Chapters 8 & 9