BROCK BIOLOGY OF MICROORGANISMS 13TH EDITION BY MADIGAN - TEST BANK

BROCK BIOLOGY OF MICROORGANISMS 13TH EDITION BY MADIGAN – TEST BANK

 

Instant Download – Complete Test Bank With Answers

 

 

Sample Questions Are Posted Below

 

 

 

MULTIPLE CHOICE.  Choose the one alternative that best completes the statement or answers the question.

 

1)

 

Growth is defined as an increase in

 

1)

 

_______

 

1. A)

 

the life span of individual cells.

 

1. B)

 

the number of cells.

 

1. C)

 

the size of individual organisms.

 

1. D)

 

the number of colonies present in a culture.

 

 

 

2)

 

Which environmental factor(s) influences microbial growth?

 

2)

 

_______

 

1. A)

 

water availability

 

1. B)

 

oxygen

 

1. C)

 

pH

 

1. D)

 

all of the above

 

 

 

3)

 

The process by which two cells arise from one is known as

 

3)

 

_______

 

1. A)

 

binary fission.

 

1. B)

 

mitosis.

 

1. C)

 

meiosis.

 

1. D)

 

conjugation.

 

 

 

4)

 

Proteins involved in prokaryotic cell division are

 

4)

 

_______

 

1. A)

 

Fts proteins.

 

1. B)

 

divisomes.

 

1. C)

 

MreB proteins.

 

1. D)

 

none of these.

 

 

 

5)

 

The time interval required for the formation of two cells from one is called the

 

5)

 

_______

 

1. A)

 

division rate.

 

1. B)

 

growth time.

 

1. C)

 

growth rate.

 

1. D)

 

generation time.

 

 

 

6)

 

When the population doubles during a constant time interval, the growth is said to be

 

6)

 

_______

 

1. A)

 

exponential.

 

1. B)

 

cartesian.

 

1. C)

 

linear.

 

1. D)

 

semilogarithmic.

 

 

 

7)

 

The time between inoculation and the beginning of growth is usually called the

 

7)

 

_______

 

1. A)

 

log phase.

 

1. B)

 

death phase.

 

1. C)

 

lag phase.

 

1. D)

 

dormant phase.

 

 

 

8)

 

In general, compared with most prokaryotic microorganisms, most eukaryotic microorganisms grow

 

8)

 

_______

 

1. A)

 

slower.

 

1. B)

 

faster.

 

1. C)

 

at about the same rate.

 

1. D)

 

at rates that are too variable to make an adequate comparison.

 

 

 

9)

 

Cryptic growth occurs when

 

9)

 

_______

 

1. A)

 

increases in cell population go unnoticed.

 

1. B)

 

the exponential curve is marked by a very long generation time.

 

1. C)

 

cells are increasing in size but not in number.

 

1. D)

 

the number of cells being generated equals the number of cells dying.

 

 

 

10)

 

Population growth is measured by

 

10)

 

______

 

1. A)

 

changes in the number of cells.

 

1. B)

 

changes in the cell mass.

 

1. C)

 

changes in the amount of nutrient(s) in the culture medium.

 

1. D)

 

changes in the number of cells and in the cell mass.

 

 

 

11)

 

When counting colonies on an agar plate,

 

11)

 

______

 

1. A)

 

it is assumed that each colony arose from only one cell.

 

1. B)

 

the medium must be suitable for colonial growth.

 

1. C)

 

only viable colonies are counted.

 

1. D)

 

All of the above apply.

 

 

 

12)

 

An agar plate for counting colonies and maximizing statistical validity should ideally contain

 

12)

 

______

 

1. A)

 

30 to 300 colonies.

 

1. B)

 

10 to 100 colonies.

 

1. C)

 

10 to 1000 colonies.

 

1. D)

 

20 to 200 colonies.

 

 

 

13)

 

Serial dilutions are generally made

 

13)

 

______

 

1. A)

 

when the appropriate viable count is unknown.

 

1. B)

 

to reach a suitable dilution while minimizing error.

 

1. C)

 

based on powers of 10, although other serial dilution factors are possible.

 

1. D)

 

All of the above apply.

 

 

 

14)

 

The number of colonies obtained in a plate count does NOT depend on the

 

14)

 

______

 

1. A)

 

inoculum volume.

 

1. B)

 

type of culture medium.

 

1. C)

 

incubation time.

 

1. D)

 

size of the colonies.

 

 

 

15)

 

Cell density in a chemostat is controlled by

 

15)

 

______

 

1. A)

 

the dilution factor.

 

1. B)

 

the concentration of the limiting nutrient.

 

1. C)

 

the size of the initial inoculum.

 

1. D)

 

all of the above.

 

 

 

16)

 

In which type of culture(s) does one find a closed system?

 

16)

 

______

 

1. A)

 

chemostat cultures

 

1. B)

 

batch culture

 

1. C)

 

continuous culture

 

1. D)

 

all of the above

 

 

 

17)

 

For most physiological experiments, it is desirable for cells to be in the

 

17)

 

______

 

1. A)

 

lag phase.

 

1. B)

 

stationary phase.

 

1. C)

 

death phase.

 

1. D)

 

exponential phase.

 

 

 

18)

 

The cardinal temperatures are the

 

18)

 

______

 

1. A)

 

minimum temperatures.

 

1. B)

 

maximum temperatures.

 

1. C)

 

optimum temperatures.

 

1. D)

 

minimum, optimum, and maximum temperatures taken together.

 

 

 

19)

 

Most organisms can tolerate a temperature range of about

 

19)

 

______

 

1. A)

 

10°C.

 

1. B)

 

15-20°C.

 

1. C)

 

50-60°C.

 

1. D)

 

25-40°C.

 

 

 

20)

 

The cytoplasmic membrane must be in a(n) ________ state for proper functioning.

 

20)

 

______

 

1. A)

 

stable

 

1. B)

 

semi-fluid

 

1. C)

 

neutral

 

1. D)

 

elastic

 

 

 

21)

 

A microbe growing in a refrigerator is likely a

 

21)

 

______

 

1. A)

 

mesophile.

 

1. B)

 

psychrophile.

 

1. C)

 

hyperthermophile.

 

1. D)

 

thermophile.

 

 

 

22)

 

Consider solution A (pH 6) and solution B (pH 9). Which of the following statements is CORRECT?

 

22)

 

______

 

1. A)

 

Solution B is 1,000 times more alkaline (basic) than solution A.

 

1. B)

 

Solution A is 300 times more acidic than solution B.

 

1. C)

 

Solution B is 3,000 times more alkaline (basic) than solution A.

 

1. D)

 

Solution A is 3 times more acidic than solution B.

 

 

 

23)

 

What makes penicillin a powerful antibiotic?

 

23)

 

______

 

1. A)

 

It can kill bacterial and fungal pathogens.

 

1. B)

 

It is nontoxic to humans.

 

1. C)

 

Most pathogens contain peptidoglycan.

 

1. D)

 

Both A) and B) are correct.

 

 

 

24)

 

Which of these statements is/are TRUE?

 

24)

 

______

 

1. A)

 

In general, prokaryotic organisms can grow at higher temperatures than eukaryotic organisms.

 

1. B)

 

Nonphototrophic organisms are able to grow at higher temperatures than phototrophic organisms.

 

1. C)

 

The most thermophilic prokaryotes are species of Archaea.

 

1. D)

 

All of the above are true.

 

 

 

25)

 

As a group, which organisms tend to be most acid-tolerant?

 

25)

 

______

 

1. A)

 

Bacteria

 

1. B)

 

Archaea

 

1. C)

 

fungi

 

1. D)

 

protists

 

 

 

26)

 

The ratio of the vapor pressure of the air in equilibrium with a substance to the vapor pressure of pure water is known as

 

26)

 

______

 

1. A)

 

vapor activity.

 

1. B)

 

osmosis.

 

1. C)

 

water activity.

 

1. D)

 

positive water balance.

 

 

 

27)

 

Organisms able to live in environments with high sugar concentrations are

 

27)

 

______

 

1. A)

 

xerophiles.

 

1. B)

 

osmophiles.

 

1. C)

 

halotolerant.

 

1. D)

 

none of the above.

 

 

 

28)

 

When water activity is low, an organism must

 

28)

 

______

 

1. A)

 

increase its internal solute concentration.

 

1. B)

 

decrease its internal solute concentration.

 

1. C)

 

decrease its external solute concentration.

 

1. D)

 

increase its external solute concentration.

 

 

 

29)

 

An organism capable of growth at full oxygen tensions of 21% is

 

29)

 

______

 

1. A)

 

aerobic.

 

1. B)

 

aerotolerant.

 

1. C)

 

microaerophilic.

 

1. D)

 

anaerobic.

 

 

 

30)

 

Oxygen in its normal ground state is referred to as

 

30)

 

______

 

1. A)

 

doublet oxygen.

 

1. B)

 

triplet oxygen.

 

1. C)

 

anhydrous oxygen.

 

1. D)

 

singlet oxygen.

 

 

 

31)

 

Which of the following forms of oxygen is/are generally toxic to living organisms?

 

31)

 

______

 

1. A)

 

hydroxyl radical

 

1. B)

 

superoxide anion

 

1. C)

 

hydrogen peroxide

 

1. D)

 

all of the above

 

 

 

32)

 

Superoxide dismutase and catalase work together to convert superoxide back to

 

32)

 

______

 

1. A)

 

oxygen.

 

1. B)

 

ozone.

 

1. C)

 

peroxide.

 

1. D)

 

none of the above.

 

 

 

33)

 

Superoxide dismutase is indispensable to

 

33)

 

______

 

1. A)

 

obligate anaerobes.

 

1. B)

 

aerotolerant anaerobes.

 

1. C)

 

aerobes.

 

1. D)

 

all of the above.

 

 

 

34)

 

Divisomes are responsible for

 

34)

 

______

 

1. A)

 

osmotolerant growth.

 

1. B)

 

psychrotolerant growth.

 

1. C)

 

thermotolerant growth.

 

1. D)

 

none of these.

 

 

 

35)

 

The partition that is a result of the inward growth of the cytoplasmic membrane and cell wall from opposing directions is known as the

 

35)

 

______

 

1. A)

 

septum.

 

1. B)

 

divisome.

 

1. C)

 

autolysin.

 

1. D)

 

colony.

 

 

 

36)

 

Formation of the divisome begins with the attachment of which protein in a ring around the center of the cell?

 

36)

 

______

 

1. A)

 

MinE

 

1. B)

 

FtsZ

 

1. C)

 

MinC

 

1. D)

 

ZipA

 

 

 

37)

 

The major shape-determining protein among prokaryotes is

 

37)

 

______

 

1. A)

 

ZipA.

 

1. B)

 

MreB.

 

1. C)

 

MinE.

 

1. D)

 

FtsZ.

 

 

 

38)

 

What is the function of bactoprenol?

 

38)

 

______

 

1. A)

 

It triggers the recruitment of FtsZ and the initiation of the divisome.

 

1. B)

 

It is responsible for forming the peptide cross-links between muramic acid residues in adjacent glycan chains.

 

1. C)

 

It supplies the energy necessary for transpeptidation to occur.

 

1. D)

 

It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane.

 

 

 

39)

 

Under what conditions would a lag phase NOT occur?

 

39)

 

______

 

1. A)

 

when an exponentially growing culture is transferred into fresh medium

 

1. B)

 

when a culture subjected to UV light is transferred into fresh medium

 

1. C)

 

when a culture is transferred from a rich medium to minimal medium

 

1. D)

 

when a stationary phase culture is transferred into fresh medium

 

 

 

TRUE/FALSE.  Write ‘T’ if the statement is true and ‘F’ if the statement is false.

 

40)

 

Knowledge of microbial growth patterns is useful in working with the control of microbial growth.

 

40)

 

______

 

 

 

41)

 

The main reactions of cell synthesis are the polymerization reactions that make macromolecules from monomers.

 

41)

 

______

 

 

 

42)

 

With a few minor exceptions, the time required for a bacterial growth cycle is generally the same, regardless of the bacterial species.

 

42)

 

______

 

 

 

43)

 

An increase in microbial density is synonymous with growth.

 

43)

 

______

 

 

 

44)

 

A growth curve can typically be plotted by monitoring a microbial population in a batch culture.

 

44)

 

______

 

 

 

45)

 

The lag phase does NOT occur if all the cells in the culture are viable.

 

45)

 

______

 

 

 

46)

 

The rates of exponential growth (in the exponential phase) vary greatly.

 

46)

 

______

 

 

 

47)

 

In the stationary phase, there is no net increase or decrease in cell number.

 

47)

 

______

 

 

 

48)

 

The death phase applies to individual cells rather than populations.

 

48)

 

______

 

 

 

49)

 

Direct microscope counting of cells is an easy and accurate method of computing the exact number of cells in a sample.

 

49)

 

______

 

 

 

50)

 

Counting chambers are used for estimating the number of cells present in a liquid culture.

 

50)

 

______

 

 

 

51)

 

For most purposes, viable counting usually gives accurate information about the number of active cells present in a culture volume.

 

51)

 

______

 

 

 

52)

 

Turbidity measurements are rapid but are not particularly accurate.

 

52)

 

______

 

 

 

53)

 

One problem with batch cultures is the change in the chemical composition of the medium as growth progresses.

 

53)

 

______

 

 

 

54)

 

In a chemostat, growth rate and growth yield can be controlled independently.

 

54)

 

______

 

 

 

55)

 

In a chemostat, the doubling rate and population density can be controlled independently.

 

55)

 

______

 

 

 

56)

 

Organisms generally respond equally to a given environmental factor.

 

56)

 

______

 

 

 

57)

 

Planktonic cells remain in suspension, while sessile cells adhere to a surface.

 

57)

 

______

 

 

 

58)

 

Irreversible cell damage is more likely to occur at low rather than high temperatures.

 

58)

 

______

 

 

 

59)

 

The optimum temperature is usually closer to the minimum temperature than the maximum temperature.

 

59)

 

______

 

 

 

60)

 

Factors affecting an organism’s minimal growth temperature are not entirely understood.

 

60)

 

______

 

 

 

61)

 

Cold environments are usually sterile.

 

61)

 

______

 

 

 

62)

 

Some microbes can grow in boiling water.

 

62)

 

______

 

 

 

63)

 

Organisms living in boiling springs must be rapid growers with fast doubling times.

 

63)

 

______

 

 

 

64)

 

Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique.

 

64)

 

______

 

 

 

65)

 

Based on studies with obligate acidophiles, high concentrations of hydrogen ions are required for membrane stability.

 

65)

 

______

 

 

 

66)

 

An alkaliphile would likely be found in soda lakes and high carbonate soils.

 

66)

 

______

 

 

 

67)

 

The optimal growth pH represents the pH of the intracellular environment.

 

67)

 

______

 

 

 

68)

 

Many obligate anaerobes are killed by oxygen.

 

68)

 

______

 

 

 

SHORT ANSWER.  Write the word or phrase that best completes each statement or answers the question.

 

69)

 

The most common type of continuous culture device is called a(n) ________.

 

69)

 

_____________

 

 

 

70)

 

The process by which macromolecules are synthesized from monomers is called ________.

 

70)

 

_____________

 

 

 

71)

 

Because two or more cells may clump together, instead of reporting “viable cell count” microbiologists often use the term ________.

 

71)

 

_____________

 

 

 

72)

 

________ is the term used to describe the maintaining of cultures in a constant environment. The system is then said to be in a(n) ________.

 

72)

 

_____________

 

 

 

73)

 

Probably the most important environmental factor affecting microbial growth is ________.

 

73)

 

_____________

 

 

 

74)

 

An organism that can grow at 0°C but whose optimum temperature is 20-40°C is considered ________. These organisms are ________ (more/less) widely distributed in nature than organisms that grow exclusively at cold temperatures.

 

74)

 

_____________

 

 

 

75)

 

Substances added to a culture to keep the pH constant are known as ________.

 

75)

 

_____________

 

 

 

76)

 

Organisms with a specific requirement for salt are known as ________.

 

76)

 

_____________

 

 

 

77)

 

FtsZ is related to ________, the important cell division protein in eukaryotes.

 

77)

 

_____________

 

 

 

78)

 

Enzymes called ________ create small openings in the prokaryotic cell wall that are formed at the FtsZ ring.

 

78)

 

_____________

 

 

 

79)

 

During stationary phase, many cellular functions continue, including ________ and some ________.

 

79)

 

_____________

 

 

 

ESSAY.  Write your answer in the space provided or on a separate sheet of paper.

 

80)

 

Use the formulas N = N02n and g = t/n.

N = final cell number, N0 = initial cell number,

n = number of generations, t = time, g = generation time.

Find the generation time if N = 2 × 108, N0 = 3 × 106 and t = 3 hours.

 

 

 

81)

 

Explain the difference between the division rate and the generation time.

 

 

 

82)

 

Explain the five major limitations to using the direct microscope count.

 

 

 

83)

 

Compare and contrast the spread plate method and the pour plate method of doing plate counts.

 

 

 

84)

 

Why must a standard curve be prepared when using turbidity measurements?

 

 

 

85)

 

Explain why a hyperthermophile is unlikely to be a human pathogen.

 

 

 

86)

 

Explain our present understanding of molecular adaptations to the cytoplasmic membrane that are present in psychrophiles.

 

 

 

87)

 

Explain our present understanding of molecular adaptations to the cytoplasmic membrane that are present in thermophiles.

 

 

 

88)

 

Would you expect a xerophilic organism to be halotolerant? Why or why not?

 

 

 

89)

 

What kind of a growth setup might an industrial microbiologist create for a product-oriented project and why?

 

 

 

90)

 

Explain why it is notable that FtsZ-type proteins have been found in mitochondria and chloroplasts.

 

 

 

91)

 

Explain why clinical medicine has an interest in understanding bacterial cell division at the molecular level.

 

 

 

92)

 

Why are microbial doubling times in nature typically longer than those obtained in the laboratory?

 

 

 

1)

 

B

 

2)

 

D

 

3)

 

A

 

4)

 

A

 

5)

 

D

 

6)

 

A

 

7)

 

C

 

8)

 

A

 

9)

 

D

 

10)

 

D

 

11)

 

D

 

12)

 

A

 

13)

 

D

 

14)

 

D

 

15)

 

B

 

16)

 

B

 

17)

 

D

 

18)

 

D

 

19)

 

D

 

20)

 

B

 

21)

 

B

 

22)

 

A

 

23)

 

D

 

24)

 

D

 

25)

 

C

 

26)

 

C

 

27)

 

B

 

28)

 

A

 

29)

 

A

 

30)

 

B

 

31)

 

D

 

32)

 

A

 

33)

 

C

 

34)

 

D

 

35)

 

A

 

36)

 

B

 

37)

 

B

 

38)

 

D

 

39)

 

A

 

40)

 

TRUE

 

41)

 

TRUE

 

42)

 

FALSE

 

43)

 

TRUE

 

44)

 

TRUE

 

45)

 

FALSE

 

46)

 

TRUE

 

47)

 

TRUE

 

48)

 

FALSE

 

49)

 

FALSE

 

50)

 

TRUE

 

51)

 

TRUE

 

52)

 

FALSE

 

53)

 

TRUE

 

54)

 

TRUE

 

55)

 

TRUE

 

56)

 

FALSE

 

57)

 

TRUE

 

58)

 

FALSE

 

59)

 

FALSE

 

60)

 

TRUE

 

61)

 

FALSE

 

62)

 

TRUE

 

63)

 

FALSE

 

64)

 

TRUE

 

65)

 

TRUE

 

66)

 

TRUE

 

67)

 

FALSE

 

68)

 

TRUE

 

69)

 

chemostat

 

70)

 

polymerization

 

71)

 

colony-forming units (CFU)

 

72)

 

Continuous culture / steady state

 

73)

 

temperature

 

74)

 

psychrotolerant / more

 

75)

 

buffers

 

76)

 

halophiles

 

77)

 

tubulin

 

78)

 

autolysins

 

79)

 

energy metabolism / biosynthetic processes (either order)

 

80)

 

The number of generations (n) must first be determined through the rearranged formula:  n = [(log N)-(log N0)]/(log 2) to determine n = 6.059 generations. Finally, the generation time (g) = t/n, which equates to nearly 0.5 hours per generation or almost 30 minutes per generation.

 

81)

 

Generation time (g) and division rate (v) are reciprocal values of each other; both are determined by monitoring exponential growth over time. Division rate is reported as the number of generations per time and is calculated by taking 1/g. The units for g are in time per generation, which is the doubling time during exponential growth.

 

82)

 

All of the following eight are potential issues associated with the direct counting method:  1) live and dead cells are indistinguishable without special staining, 2) low cell concentrations are challenging to enumerate, 3) motile cells must be immobilized, 4) precision, 5) small cells are difficult to observe and count, 6) small particulates can be mistaken for microbial cells, 7) unstained cells requires more sophisticated microscopy, and 8) very time-consuming.

 

83)

 

Answers will vary, but one benefit to the pour plate method is that larger volumes of cells can be dispensed. Many cells cannot withstand the warm temperature of molten agar (~45—50°C)

and therefore must be spread on top of an agar plate. Colonies are easier to enumerate on a two- rather than three-dimensional surface that favors the spread plate technique over the pour plate method.

 

84)

 

Answers will vary, but it should be noted that a particular OD value will correspond to a specific viable cell concentration. One such example could be a culture of Citricella sp. SE-45 was determined to have an OD540 of 0.485. This OD fit into the already-constructed standard curve to indicate that 5 × 105 viable cells are in each milliliter of broth, which can be helpful in experiments where the final cell concentration or number is critical.

 

85)

 

The human body’s temperature is approximately 37°C, which is not a favorable environment for a hyperthermophile, which has an optimal growth temperature of 80°C or higher.

 

86)

 

Non-psychrophiles do not thrive in the cold environment, in part due to predominantly having large or saturated fatty acid chains in their cytoplasmic membrane, which become increasingly rigid and waxlike with colder temperatures. The psychrophiles have higher relative concentrations of short and unsaturated fatty acids in their membrane and therefore maintain a semi-permeable membrane when exposed to less heat.

 

87)

 

Thermophilic proteins typically contain more binding (i.e., stabilizing) interactions within itself when compared to non-thermophilic proteins.

 

88)

 

Yes, xerophiles are typically halotolerant. For example, the xerophilic halotolerant fungus Xeromyces bisporus inhabits cereal, candy, and dried fruit, all of which are very dry environments that also contain salt. With all else being equal, a decrease in solvent (such as water) translates to an increase in solute (salt) concentration, and therefore a microbe capable of tolerating a low water activity likely can also tolerate higher salt concentrations.

 

89)

 

Answers will vary, but one example could be a continuous culture device (e.g., a chemostat) to be favored for the maintenance of exponential cell growth and therefore maximize cell numbers obtained over minimal time.

 

90)

 

The protein FtsZ, encoded by the gene ftsZ, which is specifically involved in prokaryotic cell division, has been identified in eukaryotes. This suggests the gene was first present in prokaryotes and that these two organelles were subsequently developed and maintained in Eukarya. Ultimately this corroborates the ideas of the endosymbiotic theory and seemingly links chloroplast and mitochondrial origins to prokaryotes.

 

91)

 

Answers will vary, but one principle of thought is that to prevent cell growth, the mechanisms involved in normal cell growth must first be understood. For example, if bacterial proteins A and B must bind together for a cell to proliferate and cause disease, a drug could be developed to irreversibly bind and disrupt bacterial protein A from being functional. Consequently, an infection could be (therapeutically) killed from a human.

 

92)

 

The general theme should be on how lab conditions are designed to optimally grow a microorganism (e.g., pH, substrate(s), temperature, vitamins) and minimize pressure. In the environment this microbe often is in conditions that are less than ideal, where they likely will encounter competition for growth substrates and other essential chemicals.