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Chapter 7 Microbiology

68 Questions
Microbiology Quizzes & Trivia

Chapter 7 Microbiology

Questions and Answers
  • 1. 
    Most bacterial and archaeal cells divide by  
    • A. 

      Mitosis

    • B. 

      Meiosis

    • C. 

      Binary fission

    • D. 

      All of the above

  • 2. 
    All bacterial and archaeal cells are diploid.  
    • A. 

      True

    • B. 

      False

  • 3. 
    Which of the following is the correct order for binary fission?  
    • A. 

      A septum forms at midcell, the cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell

    • B. 

      The cell elongates, a septum forms at midcell, the cell replicates its chromosome, and separates the chromosome into the two parts of the cell

    • C. 

      The cell elongates, replicates its chromosome, and separates the chromosome into the two parts of the cell, and a septum forms at midcell

    • D. 

      None of the above

  • 4. 
    The __________ is a group of proteins needed for DNA synthesis that assembles at the origin of replication.  
    • A. 

      Septum

    • B. 

      Replisome

    • C. 

      Prospore

    • D. 

      None of the above

  • 5. 
    The process of forming a cross wall between two daughter cells is known as  
    • A. 

      Replication

    • B. 

      Septation

    • C. 

      Sporulation

    • D. 

      Mitosis

  • 6. 
    The cell wall of bacteria constrains the ___________ _________ that results from the osmolarity of the cytoplasmic contents.  
  • 7. 
    The site at which replication of DNA starts in bacterial cells is known as the __________ of ___________. (answer, answer)  
  • 8. 
    The purpose of the penicillin binding proteins is to link phospholipids together in the cellular membrane.  
    • A. 

      True

    • B. 

      False

  • 9. 
    The actin-like protein that seems to be involved in determining cell shape is  
    • A. 

      MreB

    • B. 

      ActA

    • C. 

      SpnC

    • D. 

      FtsZ

  • 10. 
    During cytokinesis, a critical step in septation is the assembly of the  
    • A. 

      Replisome

    • B. 

      Spindle body

    • C. 

      Z ring

    • D. 

      Cytoskeletal spiral

  • 11. 
    The limitation on microbial growth rate at high nutrient levels is  
    • A. 

      The rate of protein synthesis

    • B. 

      The rate of DNA replication

    • C. 

      The saturation of the transport proteins for nutrient uptake.

    • D. 

      All of the choices

  • 12. 
    The total number of viable microorganisms remains constant in stationary phase because  
    • A. 

      There is a balance between cell division and cell death.

    • B. 

      There is a cessation of cell division even though the cells may remain metabolically active.

    • C. 

      Either there is a balance between cell division and cell death or there is a cessation of cell division even though the cells may remain metabolically active.

    • D. 

      None of the choices

  • 13. 
    Cells may enter stationary phase because of  
    • A. 

      The depletion of an essential nutrient

    • B. 

      A lack of available oxygen

    • C. 

      The accumulation of toxic waste products

    • D. 

      All of the choices

  • 14. 
    A culture in a closed vessel to which no additional medium is added and from which no waste products are removed is called a __________ culture.  
    • A. 

      Continuous

    • B. 

      Batch

    • C. 

      Fed-batch

    • D. 

      Semicontinuous

  • 15. 
    • A. 

      1 hour

    • B. 

      2 hours

    • C. 

      3 hours

    • D. 

      4 hours

  • 16. 
    Microorganisms are most nearly uniform in terms of chemical and physiological properties during __________ phase.  
    • A. 

      Lag

    • B. 

      Exponential

    • C. 

      Stationary

    • D. 

      Decline

  • 17. 
    Which of the following is a reason for the occurrence of a lag phase in a bacterial growth curve?  
    • A. 

      The cells may be old and depleted of ATP, essential cofactors, and ribosomes that must be synthesized before growth can begin.

    • B. 

      The medium may be different from the previous growth medium so that the cells must synthesize new enzymes to use different nutrients.

    • C. 

      The organisms may have been injured and require time to recover.

    • D. 

      All of these are potential reasons.

  • 18. 
    When a young, vigorously growing culture of bacteria is transferred to fresh medium of the same composition, the lag phase is usually short or absent.  
    • A. 

      True

    • B. 

      False

  • 19. 
    During the lag phase of microbial growth, the cells are metabolically inactive.  
    • A. 

      True

    • B. 

      False

  • 20. 
    The length of the lag phase of growth can vary depending on  
    • A. 

      The condition of the microorganisms

    • B. 

      The nature of the growth medium

    • C. 

      The temperature

    • D. 

      All of the choices

  • 21. 
    When a young, vigorously growing culture of bacteria is transferred to fresh medium of different composition, the lag phase is usually short or absent.  
    • A. 

      True

    • B. 

      False

  • 22. 
    The growth rate of a given species of microorganism is dependent on the composition of the medium in which it is grown.  
    • A. 

      True

    • B. 

      False

  • 23. 
    Microbial __________ is an increase in cell constituents that may or may not be accompanied by an increase in cell number.  
  • 24. 
    The __________ __________ is the length of time it takes for a population of microorganisms to double in number. (2 words)  
  • 25. 
    If all cell components are synthesized at constant rates relative to one another, the culture is said to be in __________ growth; however, if the rates of synthesis of some components change relative to the rates of synthesis of other components, the culture is said to be in __________ growth. (answer, answer)  
  • 26. 
    Growth is said to be __________ when all cellular components are synthesized at constant rates relative to one another.  
  • 27. 
    At 4:00 p.m. a closed flask of sterile broth is inoculated with 10,000 cells. The lag phase lasts 1 hour. At 9:00 p.m. the culture enters stationary phase with a population of 65 million cells. At what time is the population half maximal?  
    • A. 

      6:30

    • B. 

      7:20

    • C. 

      8:20

    • D. 

      8:40

  • 28. 
    At 4:00 p.m. a closed flask of sterile broth is inoculated with 10,000 cells. The lag phase lasts 1 hour. At 9:00 p.m. the log phase culture has population of 65 million cells. The approximate number of generations that has occurred is  
    • A. 

      5

    • B. 

      13

    • C. 

      21

    • D. 

      27

  • 29. 
    Which of the following can be used to estimate the number of microorganisms in a culture?  
    • A. 

      Direct counts of microbial cells

    • B. 

      Counts of viable cells using colony growth procedures

    • C. 

      Measurements of microbial biomass

    • D. 

      All of the choices

  • 30. 
    Which of these methods can be used to determine the number of viable microorganisms in a sample?  
    • A. 

      Light scattering in a spectrophotometer

    • B. 

      Measuring total cell mass

    • C. 

      Measuring colony forming units per ml

    • D. 

      Counting a known volume of cells in a hemocytometer

  • 31. 
    At 4:00 p.m. a closed flask of sterile broth is inoculated with 10,000 cells. The lag phase lasts 1 hour. At 9:00 p.m. the log phase culture has a population of 65 million cells. The mean generation time is approximately  
    • A. 

      10 minutes

    • B. 

      20 minutes

    • C. 

      30 minutes

    • D. 

      40 minutes

  • 32. 
    A culture system with constant environmental conditions maintained through continual provision of nutrient and removal of wastes is called __________ culture system.  
    • A. 

      Continuous

    • B. 

      Batch

    • C. 

      Fed-batch

    • D. 

      Semicontinuous

  • 33. 
    An open system in which the growth rate is maintained by adding a nutrient (present in limiting quantities) at the same rate that medium containing microorganisms is removed is called  
    • A. 

      Manostat

    • B. 

      Chemostat

    • C. 

      Turbidostat

    • D. 

      Culturostat

  • 34. 
    An open system in which the growth rate is maintained by the removal and addition of media at such a rate as to maintain a constant cell density is called a  
    • A. 

      Manostat

    • B. 

      Chemostat

    • C. 

      Turbidostat

    • D. 

      Culturostat

  • 35. 
    One of the major advantages of a continuous culture system is that the cells can be maintained in the exponential growth phase for extended periods of time.  
    • A. 

      True

    • B. 

      False

  • 36. 
    In a continuous culture system, the rate at which media is added and removed is called the __________ rate.  
    • A. 

      Dilution

    • B. 

      Chemostatic

    • C. 

      Pass-through

    • D. 

      Flow-through

  • 37. 
    Which of the following is considered a cardinal growth temperature?  
    • A. 

      The minimum temperature

    • B. 

      The maximum temperature

    • C. 

      The optimum temperature

    • D. 

      All of these are considered cardinal growth temperatures

  • 38. 
    Organisms that grow well at 0C and have optimum growth temperatures of 15C or lower are called  
    • A. 

      Psychrothrophs

    • B. 

      Psychrophiles

    • C. 

      Frigiphiles

    • D. 

      Mesophiles

  • 39. 
    Organisms that grow at 0C and have a maximum growth temperature of 35C are called  
    • A. 

      Psychrotrophs

    • B. 

      Psychrophiles

    • C. 

      Frigiphiles

    • D. 

      Mesophiles

  • 40. 
    Organisms that do not require oxygen for growth but grow better in its presence are called  
    • A. 

      Facultative anaerobes

    • B. 

      Microaerophiles

    • C. 

      Aerotolerant

    • D. 

      Anoxygenic

  • 41. 
    Organisms that ignore oxygen and grow equally well in its presence or absence are called  
    • A. 

      Facultative anaerobes

    • B. 

      Microaerophiles

    • C. 

      Aerotolerant

    • D. 

      Anoxygenic

  • 42. 
    Organisms that are damaged by the normal atmospheric levels of oxygen (20%) but require oxygen at levels of 2–10% for growth are called  
    • A. 

      Facultative anaerobes

    • B. 

      Microaerophiles

    • C. 

      Aerotolerant

    • D. 

      Anoxygenic

  • 43. 
    When a microorganism is placed in a(n) __________ solution, water will enter into the cell and cause it to burst unless something is done to prevent this.  
    • A. 

      Hypotonic

    • B. 

      Isotonic

    • C. 

      Hypertonic

    • D. 

      Osmotonic

  • 44. 
    The membranes of psychrophilic bacteria have relatively high levels of __________ fatty acids, which allow them to remain semi-fluid at cold temperatures.  
    • A. 

      Saturated

    • B. 

      Unsaturated

    • C. 

      Sterol

    • D. 

      Aromatic

  • 45. 
    Organisms that are not drastically affected by increased pressure are called  
    • A. 

      Barotolerant

    • B. 

      Osmotolerant

    • C. 

      Barophilic

    • D. 

      Osmophilic

  • 46. 
    Organisms that require increased pressure for optimum growth are called  
    • A. 

      Barotolerant

    • B. 

      Osmotolerant

    • C. 

      Barophilic

    • D. 

      Osmophilic

  • 47. 
    Most microorganisms maintain their internal pH  
    • A. 

      Near neutral (pH 7).

    • B. 

      Near their optimum growth pH.

    • C. 

      Slightly acidic (pH 4–6).

    • D. 

      Slightly alkaline (pH 8–10).

  • 48. 
    Organisms that grow near deep-sea volcanic vents are likely to be  
    • A. 

      Psychrophilic

    • B. 

      Psychrotrophic

    • C. 

      Mesophilic

    • D. 

      Thermophilic

  • 49. 
    Organisms that grow near deep-sea volcanic vents are likely to be  
    • A. 

      Alkylophilic

    • B. 

      Acidophilic

    • C. 

      Barophilic or barotolerant

    • D. 

      Picrophilic

  • 50. 
    Organisms that grow in the mud under relatively nonturbulent bodies of water are likely to be  
    • A. 

      Obligate aerobes

    • B. 

      Thermophilic

    • C. 

      Barophilic

    • D. 

      Anaerobes

  • 51. 
    The primary mechanism by which DNA is damaged by ultraviolet radiation involves the formation of thymine dimers.  
    • A. 

      True

    • B. 

      False

  • 52. 
    Obligate anaerobes are usually poisoned by molecular oxygen but may grow in aerobic habitats if associated with facultative anaerobes that use up all available oxygen.  
    • A. 

      True

    • B. 

      False

  • 53. 
    DNA of thermophiles is stabilized by binding of special nucleoid-associated proteins.  
    • A. 

      True

    • B. 

      False

  • 54. 
    Membranes of some thermophilic Archaea are stabilized by ether linked phospholipids.  
    • A. 

      True

    • B. 

      False

  • 55. 
    Organisms that can grow in habitats with low water activity by maintaining a high internal salt concentration are called __________ organisms.  
  • 56. 
    Organisms that require high levels of sodium chloride in order to grow are called __________ organisms.  
  • 57. 
    Organisms that have their optimum growth pH between 0.0 and 5.5 are called __________.  
  • 58. 
    Membranes of thermophilic bacteria are stabilized by phospholipids with  
    • A. 

      Fatty acids that tend to be more saturated.

    • B. 

      Fatty acids that have lower molecular weights.

    • C. 

      Fatty acids that have more double bonds.

    • D. 

      All of the choices

  • 59. 
    Organisms that have their optimum growth pH between 5.5 and 8.0 are called __________.  
  • 60. 
    Organisms that have their optimum growth pH between 8.5 and 11.5 are called _______.  
  • 61. 
    Organisms that grow best at pH levels above 10 are called __________ __________. (2 words)  
  • 62. 
    Many microbes that live in environments where there is high exposure to light use _______________ to provide protection from photoxidation by singlet oxygen.  
  • 63. 
    Organisms with growth temperature maxima between 85 and 113C are referred to as __________.  
  • 64. 
    Complex microbial communities that grow tightly adhered to surfaces are called __________.  
  • 65. 
    Quorum sensing in Gram-positive bacteria generally involves the use of ____________ as the external signaling molecules.  
  • 66. 
    A common type of autoinducer found in gram-negative bacteria are acyl homoserine lactones (AHL).  
    • A. 

      True

    • B. 

      False

  • 67. 
    A microbial environment containing high nutrient concentrations is called an oligotrophic environment.  
    • A. 

      True

    • B. 

      False

  • 68. 
    Quorum sensing  
    • A. 

      Is a phenomenon in which bacteria monitor their own population density.

    • B. 

      Depends on the sensing of signal protein molecules.

    • C. 

      Plays an important role in formation of biofilms by Pseudomonas aeruginosa.

    • D. 

      All of the choices