Microbiology Chapter 4

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  1. How do prokaryotes divide?
    Binary Fission
  2. At what rate do prokaryotic cells divide?
  3. What is Generation Time?
    The time it takes for the population to double
  4. What is the growth calculation?
    Nt = No x 2^n
  5. What does Nt represent?
    number of cells in a population at a time
  6. What does No represent?
    The original number of cells in a population
  7. What does 2n represent?
    2 to the number of divisions in x time
  8. What is a biofilm?
    a community of microbes
  9. Name a beneficial biofilm and a hazardous one
    • Beneficial: Waste Treatment Plants
    • Hazardous: Dental Plaque
  10. What is a medical issue associated with biofilms?
    The can be antibiotic resistant
  11. Name two types of diseases effected by biofilms
    • Chronic ear infections
    • cystic fibrosis
  12. Why can biofilms be cooperative?
    Microbes help one another grow
  13. Why can biofilms be competitive?
    Some bacteria make toxic compounds
  14. What is a pure culture?
    The growth bacteria of one species only
  15. What is needed for a culture medium?
    • Contains nutrients dissolved in water
    • may be liquid (broth) or a solid medium
  16. What are the benefits of using agar?
    • Not destroyed at high temperatures
    • liquifies above 95
    • solidifies below 45
    • few microbes can degrade it
  17. What is a stock culture?
    stored bacteria
  18. What are the two systems used to grow bacteria?
    • Closed system
    • Open system
  19. What is a closed system?
    • A Batch Culture
    • Gives characteristic growth curve
    • Nutrients are not renewed; wastes are not removed
  20. What is an open system?
    • A Continuous culture
    • Nutrients are added; wastes are removed
  21. What are the phases of a growth curve?
    • Lag Phase
    • Log Phase
    • Stationary Phase
    • Death phase
    • Prolonged decline phase
  22. What are the axises on a growth curve?
    • X- Time
    • Y- Number of cells on a logarithmic scale
  23. What occurs during the lag phase
    • cell numbers do not increase
    • Cells begin to sythesize enzymes
  24. What occurs during the Exponential (log) phase
    • cells divide at a constant rate
    • cells are sensitive to antibiotics
    • cells produce metabolites
  25. Why are cells susceptible to antibiotics during the Log phase?
    Most antibiotics target cells during growth
  26. What is a primary metabolite?
    • Created during initial Log phase
    • important commercially
  27. What is a secondary metabolite?
    • Created during later Log phase
    • Antibiotics
  28. What occurs during the Stationary phase?
    • Nutrients are too low to sustain growth
    • total number of cells remain constant
  29. What occurs during the Death Phase?
    Total number of viable (living) cells decrease at a constant rate
  30. What occurs during the Phase of prolonged decline
    • some fraction of bacteria survive
    • They've adapted to conditions
  31. What is the difference of growing microbes in a solid medium vs. a broth medium?
    • Solid medium: center depleted nutrients more quickly, edge has plenty of O2 and nutrients
    • Broth: Nutrients occur evenly throughout medium
  32. What are the 4 major conditions that influence growth?
    • Temperature
    • Atmosphere (O2)
    • pH
    • Water Availability
  33. What is a psychrophile?
    • -5 - 15
    • Found in Arctic and Antarctic region
  34. What is a psychrotroph?
    • 20 - 30 
    • Important in food spoilage
  35. What is a mesophile?
    • 25 - 45 
    • Most pathogens
  36. What is a Thermophile?
    • 45-70 
    • Common in hot springs
  37. What is hyperthermophile
    • 70-110
    • Usually archaea
    • Found in hydrothermal vents
  38. What do biofilms consist of?
    microbes that secrete polysaccharides that other microbes attach to
  39. What is a batch culture
    Bacteria grown in a lab where nutrients are not replenished and wastes are not removed
  40. What is a continuous culture?
    When bacteria are grown in a lab where nutrients are added and wastes removed
  41. Colony Growth
    • A cell's place within a solid medium can effect it's survival
    • Outer edge- more nutrients
    • center- less
  42. How does refrigeration help with bacterial growth?
    inhibits mesophiles, but not psychotrophs or psychorphiles
  43. What is an obligate aerobe?
    A microbe that cannot grow without O2
  44. What is a Facultative Anaerobe?
    A microbe that grows better with O2, but can grow without it
  45. What is a Microaerophile?
    • A microbe that requires small amounts of O2
    • ex. Helicobacter pylori-causes ulcers
  46. What is an aerotolerant Anaerobe?
    • Isn't affected by O2
    • ex. Streptococcus pyogen- strep throat
  47. What is a reactive Oxygen Species (ROS)
    • Harmful derivates that are formed as by-products of aerobic respiration
    • ex. O2- (superoxide) H2O2 (hydrogen peroxide)
  48. What is superoxide dismutase?
    Created by aerobic microbes to inactivate O2- and convert it to O2 and H2O2
  49. What is Catalase?
    Created by aerobic microbes to convert H2O2 into O2 and H2O
  50. How do aerobic respiration molecules defend against by products?
    Creating Superoxide Dismutase and Catalase
  51. What are the 3 different pH tolerant microbes?
    • Neutrophiles: pH 5-8
    • Acidophile: pH < 5.5
    • Alkaliphile: pH >8.5
  52. What is plasmolysis?
    When the solute concentration outside the cell is higher, water diffuses out via osmosis. This causes the cytoplasm to shrink away from the cell wall due to dehydration
  53. What are the two types of water availability microbes?
    • Halotolerant: tolerate Na concentrations up to 10%
    • Halphile: require high levels of Na
    • Extreme Halophile: require extremely high levels of Na
  54. What are the Major Elements?
    C, O, H, N, S, P, K, Mg, Ca, Fe
  55. What do the major elements do?
    Chemical elements that make up cell parts
  56. What are heterotrophs?
    Microbes that use Organic Carbon
  57. What are Autotrophs?
    Microbes that use inorganic Carbon
  58. What is Carbon Fixation?
    Converting inorganic Carbon to Organic Carbon
  59. What is Nitrogen Fixation?
    • Conversion of N2 (g) into Ammonia
    • Unique to prokaryotes
  60. What are limiting nutrients?
    • limits growth because it's the lowest concentration relative to need
    • ex. Ph and Fe
  61. What are Trace Elements?
    • needed in small amounts
    • ex. Cobalt, Zinc, Copper, Molybdenum and manganese
  62. What are growth factors?
    Compounds required for growth that the bacteria cannot sythesis itself
  63. What are phototrophs?
    Obtain energy from sunlight
  64. What are Chemotrophs?
    Obtain energy from chemical compounds
  65. What are Photoautotrophs?
    use light and CO2, Carbon Fixation
  66. What are Photoheterotrophs?
    Use light and Organic Carbon
  67. What are Chemolithautotrophs?
    Use inorganic compounds and CO2
  68. What are Chemoorganoheterotrophs?
    Use organic compounds and Organic Compounds
  69. What is a complex Media?
    • Contains a variety of ingredients
    • highly variable composition
  70. What is a Chemically Defined Media
    • composed of exact amounts of chemicals
    • used for fastidious compounds
  71. What is selective media?
    inhibit growth of species to easier isolate the one being sought
  72. What is differential media?
    Contains substances that change the microbes in a recognizable way
  73. What is a single cell multiplied to form a visible mass of cells?
  74. Name 4 reason Agar is useful
    • Few microbes degrade agar
    • Not destroyed at high temps
    • Easy to add nutrients into
    • remains solid over the temperature range in which bacteria grow
  75. What occurs after cytoplasm shrinks and the cell dies from osmosis out of the cell?
  76. What is Plasmolysis?
    When the cytoplasm shrinks away from the cell way from dehydration
  77. What is Carbon used for in microbes?
    a componenet of amino acids, lipids, nucleic acids and sugars
  78. What is a Heterotroph?
    uses Organic Carbon
  79. What is an Autotroph?
    Uses inorganic carbon
  80. What is Nitrogen used for in cells
    to make amino acids and nucleic acids
  81. what is sulfur used for in cells?
    Creating some amino acids
  82. What is phosphorous used for in cells?
    Creating nucleic acids, membrane lipids and ATP
  83. What are Trace elements needed for?
    supporting microbial growth
Card Set
Microbiology Chapter 4
Microbiology Chapter 4
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