Microbiology Chapter 6.txt

  1. Chapter 6
    • Microbial Growth
  2. Acidophile
    A bacterium that grows below pH 4
  3. Aerotolerant Anaerobe
    An organism that does not use molecular oxygen (02) but is not affected by its presence
  4. Agar
    A complex polysaccharide derived from a marine alga and used as a solidifying agent in culture media
  5. Bacterial Growth Curve
    A graph indicating the growth of a bacterial population over time
  6. Binary Fission
    Prokaryotic cell reproduction by division into two daughter cells
  7. Budding
    (1) Asexual reproduction beginning as a protuberance from a parent cell that grows to become a daughter cell. (2) Release of an enveloped virus through the plasma membrane of an animal cell
  8. Catalase
    An enzyme that catalyzes the breakdown of hydrogen peroxide to water and oxygen
  9. Chemically Defined Medium
    A culture medium in which the exact chemical composition is known
  10. Colony
    A visible mass of microbial cells arising from one cell or from a group of the same microbes
  11. Culture
    Microorganisms that grow and multiply in a container of culture medium
  12. Culture Medium
    The nutrient material prepared for growth of microorganisms in a laboratory
  13. Death Phase
    The period of logarithmic decrease in a bacterial population; also called logarithmic decline phase
  14. Direct Microscopic Count
    Enumeration of cells by observation through a microscope
  15. Enrichment Culture
    A culture medium used for preliminary isolation that favors the growth of a particular microorganism
  16. Extreme Halophile
    An organism that requires a high salt concentration for growth
  17. Extreme Thermophile
    An organism whose optimum growth temperature is at least 80 c; also called extreme thermophile
  18. Facultative Anaerobe
    An organism that can grow with or without molecule oxygen (02)
  19. Facultative Halophile
    An organism capable of growth in, but not requiring, 1-2% salt
  20. Filtration
    The passage of a liquid or gas through a screenlike material; a 0.45 -um filter removes most bacteria
  21. Generation Time
    The time required for a cell or population to double in number
  22. Hydroxyl Radical
    A toxic form of oxygen (OH*) formed in cytoplasm by ionizing radiation and aerobic respiration
  23. Hyperthermophile
    An organism whose optimum growth temperature is at least 80 C; also called extreme thermophile
  24. Inoculum
    A culture medium in which microorganisms are implanted
  25. Lag Phase
    The time interval in a bacterial growth curve during which there is no growth
  26. Log Phase
    The period of bacterial growth or logarithmic increase in cell numbers; also called exponential growth phase
  27. Maximum Growth Temperature
    The highest temperature at which a species can grow
  28. Mesophile
    An organism that grows between about 10 C and 50 C; a moderate-temperature-loving microbe
  29. Microaerophile
    An organism that grows best in an environment with less molecular oxygen (O2) than is normally found in air
  30. Most Probable Number (MPN) Method
    A statistical determination of the number of coliforms per 100 ml of water or 100 g of food
  31. Nutrient Agar
    Nutrient broth containing agar
  32. Nutrient Broth
    A complex medium made of beef extract and peptone
  33. Obligate Aerobe
    An organism that requires molecular oxygen (O2) to live
  34. Obligate Anaerobe
    An organism that does not use molecular oxygen (O2) and is killed in the presence of O2
  35. Obligate Halophile
    An organism that requires high osmotic pressures such as high concentrations of NaCl
  36. Optimum Growth Temperature
    The temperature at which a species grows best
  37. Organic Growth Factor
    An essential organic compound that an organism is unable to synthesize
  38. Peroxidase
    An enzyme that breaks down hydrogen peroxide
  39. Peroxide Anion
    An oxygen anion consisting of two atoms of oxygen (02 2-)
  40. Plasmolysis
    Loss of water from a cell in a hypertonic enviroment
  41. Plate Count
    A method of determining the number of bacteria in a sample by counting the number of colony-forming units on a solid culture medium
  42. Pour Plate Method
    A method ofinoculating a solid nutrient medium by mixing bacteria in the melted medium and pouring the medium into a Petri dish to solidify
  43. Psychrophile
    An organism that grows best at about 15 C and does not grow above 20 C; a cold-loving microbe
  44. Serial Dilution
    The process of diluting a sample several times
  45. Singlet Oxygen
    Highly reactive molecular oxygen (O2 -)
  46. Spread Plate Method
    A plate count method in which inoculum is spread over the surface of a solid culture medium
  47. Stationary Phase
    The period in a bacterial growth curve when the number of cells dividing equals the number dying
  48. Sterile
    Free of microorganisms
  49. Streak Plate Method
    A method of isolating a culture by spreading microorganisms over the surface of a solid culture medium
  50. Superoxide Dismutase (SOD)
    An enzyme that destroys superoxide free radicals
  51. Superoxide Free Radical
    A toxic form of oxygen (O2 -) formed during aerobic respiration
  52. Symbiosis
    The living together of two different organisms or populations
  53. Thermophile
    An organism whose optimum growth temperature is between 50 C and 60 C; a heat-loving microbe
  54. Trace Element
    A chemical element required in small amounts for growth
  55. Turbidity
    The cloudiness of a suspension
Card Set
Microbiology Chapter 6.txt
Microbial Growth