Question 1

Whether an organism is a phototroph or a chemotroph depends on its source of energy.

Accepted Answer

A) True 
 B)False

Question 2

A loopful of bacteria containing 1000 bacterial cells is inoculated into a nutrient broth and incubated.After a negligible lag phase, the culture goes into exponential growth for two hours.The generation time for the bacterium is fifteen minutes.Which equation is the correct one to determine the number of cells present after two hours of log phase growth?

Accepted Answer

A)  1000 X 2 X 2 X 15
B)  1000 X 28
C)  1000 X 16
D)  1000 X 22E) B) and D)
F) B) and C)

Question 3

The cell wall will help prevent the cell from bursting in ______ conditions.

Accepted Answer

A)  hypotonic
B)  mesotonic
C)  hypertonic
D)  isotonicE) B) and D)
F) A) and C)

Question 4

A closed culture system is used to determine a population growth curve.

Accepted Answer

A) True 
 B)False

Question 5

The term facultative refers to

Accepted Answer

A)  using oxygen for metabolism.
B)  using light for energy production.
C)  existing in a very narrow niche.
D)  the ability to exist in a wide range of conditions.
E)  using chemicals for energy production.F) A) and B)
G) B) and D)

Question 6

Endospore-forming bacteria like Bacillus species begin the sporulation process with an asymmetric cell division to produce two cells with different fates.One will differentiate into the endospore, and the other is the sporangium that will ultimately lyse to release the mature endospore.(Review Process Figure 4.24.)  During this asymmetric cell division, one of the compartments does not receive an intact copy of the chromosome.Which compartment can function with only part of the genome and why?

Accepted Answer

A)  The sporangium; much of the genome is "junk DNA" and not required for endospore maturation.
B)  The sporangium; it supports endospore development and then lyses.
C)  The endospore; the endospore is built from the outside via the sporangium and not from the inside.
D)  The endospore; it is a dormant stage and requires very little to maintain its dormancy.E) B) and D)
F) A) and D)

Question 7

What is the difference between mutualism and synergism?

Accepted Answer

A)  In a synergistic relationship, both organisms benefit, but in a mutualistic relationship both organisms are harmed.
B)  In a mutualistic relationship, both organisms benefit, but in a synergistic relationship both organisms are harmed.
C)  In a synergistic relationship, the organisms cannot survive without each other.
D)  In a mutualistic relationship, the organisms are dependent upon each other.E) B) and C)
F) A) and B)

Question 8

Organisms called _____ live on or in the body of a host and cause some degree of harm.

Accepted Answer

A)  aerobes
B)  pathogens
C)  commensals
D)  mesophiles
E)  halophilesF) A) and C)
G) A) and B)

Question 9

The time interval from parent cell to two new daughter cells is called ______.

Accepted Answer

A)  the generation time
B)  the lag time
C)  the culture time
D)  binary fission
E)  the death phaseF) B) and E)
G) All of the above

Question 10

Facilitated diffusion is limited by

Accepted Answer

A)  osmotic pressure.
B)  the size of the pores in the membrane.
C)  the size of the cell.
D)  the substrate concentration.
E)  carrier proteins in the membrane.F) A) and D)
G) None of the above

Question 11

Most microorganisms can only grow in habitats that are similar to human body conditions.

Accepted Answer

A) True 
 B)False

Question 12

As described in "A Note About Bacterial Reproduction -- and the "Culture Bias,"" the organism Epulopiscium does not divide by binary fission.Rather, each cell increases in size and divides to produce multiple daughter cells that are held within the original cell well.After lysis, those daughters are released to repeat the process. Assuming Epulopiscium could be grown in pure culture in the laboratory in broth and on solid media (it currently cannot) , which method would be best for measuring the increase in biomass during growth?

Accepted Answer

A)  The viable plate count; each colony derives from a single cell and the number of colonies equals the number of cells.
B)  Turbidity readings from a spectrophotometer; the increase in biomass will directly vary with the turbidity of the culture.
C)  Chemostat growth; it will prevent the culture from entering the death phase.
D)  Direct microscopic count; the experimenter can directly count the number of cells and extrapolate to the biomass.E) A) and B)
F) All of the above

Question 13

What type of medium is used to demonstrate oxygen requirements of microbes?

Accepted Answer

A)  Sodium chloride
B)  Blood agar
C)  Sulfite polymyxin sulfadiazine
D)  ThioglycollateE) B) and C)
F) A) and D)

Question 14

An organism that grows slowly in the cold but has an optimum growth temperature of 32°C is called a(n)  ______.

Accepted Answer

A)  thermophile
B)  facultative psychrophile
C)  psychrophile
D)  thermoduric microbe
E)  extremophileF) C) and E)
G) A) and E)

Question 15

Calcium is required for bacteria because it

Accepted Answer

A)  stabilizes the ribosomes.
B)  stabilizes the cell wall.
C)  maintains cellular pH.
D)  makes strong cell walls.
E)  stabilizes the nucleoid.F) A) and D)
G) A) and C)

Question 16

Which compound has the highest concentration in a cell?

Accepted Answer

A)  NH3
B)  CO2
C)  H2O
D)  CH4
E)  GlucoseF) None of the above
G) A) and B)

Question 17

The phase of the bacterial growth curve that shows the maximum rate of cell division is the ______.

Accepted Answer

A)  death phase
B)  lag phase
C)  prophase
D)  exponential phase
E)  stationary phaseF) D) and E)
G) A) and B)

Question 18

You inoculate a bacterium into three tubes of nutrient broth medium containing added salt: 0.5% NaCl, 5% NaCl, and 15% NaCl.After incubation, you notice significant turbidity in the 15% NaCl medium and modest turbidity in the 5% NaCl medium.There is no growth in the third tube.This organism would be termed ______.

Accepted Answer

A)  osmophobic
B)  halophilic
C)  haloduric
D)  barophilicE) B) and C)
F) All of the above

Question 19

In a close relationship, a change in one partner that results from a change in the other partner is termed ______.

Accepted Answer

A)  mutualism
B)  symbiosis
C)  synergism
D)  coevolution
E)  antibiosisF) B) and E)
G) C) and E)

Question 20

Which statement is correct regarding microbial growth on food at refrigeration temperatures?

Accepted Answer

A)  The absence of light in the refrigerator greatly reduces the growth of most microbial pathogens.
B)  Most food does not have enough oxygen content for microorganisms to thrive.
C)  There is no growth of microbes in food in the refrigerator; the cold temperature kills or inactivates microbial cells.
D)  The growth of microbes in food depends on their optimal growth temperature; some grow slowly and others faster.E) None of the above
F) B) and D)

Exam 7: Microbial Nutrition, Ecology, and Growth

The phase of the bacterial growth curve that shows the maximum rate of cell division is the ______.

Correct Answer
verified

A closed culture system is used to determine a population growth curve.

Correct Answer
verified

Correct Answer
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The cell wall will help prevent the cell from bursting in ______ conditions.

Correct Answer
verified

Which statement is correct regarding microbial growth on food at refrigeration temperatures?

Correct Answer
verified

What is the difference between mutualism and synergism?

Correct Answer
verified

Facilitated diffusion is limited by

Correct Answer
verified

Organisms called _____ live on or in the body of a host and cause some degree of harm.

Correct Answer
verified

An organism that grows slowly in the cold but has an optimum growth temperature of 32°C is called a(n) ______.

Correct Answer
verified

Correct Answer
verified

The time interval from parent cell to two new daughter cells is called ______.

Correct Answer
verified

Calcium is required for bacteria because it

Correct Answer
verified

In a close relationship, a change in one partner that results from a change in the other partner is termed ______.

Correct Answer
verified

What type of medium is used to demonstrate oxygen requirements of microbes?

Correct Answer
verified

Whether an organism is a phototroph or a chemotroph depends on its source of energy.

Correct Answer
verified

Most microorganisms can only grow in habitats that are similar to human body conditions.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The term facultative refers to

Correct Answer
verified

Which compound has the highest concentration in a cell?

Correct Answer
verified

Exam 7: Microbial Nutrition, Ecology, and Growth

The phase of the bacterial growth curve that shows the maximum rate of cell division is the ______.

Correct AnswerverifiedShow Answer

A closed culture system is used to determine a population growth curve.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The cell wall will help prevent the cell from bursting in ______ conditions.

Correct AnswerverifiedShow Answer

Which statement is correct regarding microbial growth on food at refrigeration temperatures?

Correct AnswerverifiedShow Answer

What is the difference between mutualism and synergism?

Correct AnswerverifiedShow Answer

Facilitated diffusion is limited by

Correct AnswerverifiedShow Answer

Organisms called _____ live on or in the body of a host and cause some degree of harm.

Correct AnswerverifiedShow Answer

An organism that grows slowly in the cold but has an optimum growth temperature of 32°C is called a(n) ______.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The time interval from parent cell to two new daughter cells is called ______.

Correct AnswerverifiedShow Answer

Calcium is required for bacteria because it

Correct AnswerverifiedShow Answer

In a close relationship, a change in one partner that results from a change in the other partner is termed ______.

Correct AnswerverifiedShow Answer

What type of medium is used to demonstrate oxygen requirements of microbes?

Correct AnswerverifiedShow Answer

Whether an organism is a phototroph or a chemotroph depends on its source of energy.

Correct AnswerverifiedShow Answer

Most microorganisms can only grow in habitats that are similar to human body conditions.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The term facultative refers to

Correct AnswerverifiedShow Answer

Which compound has the highest concentration in a cell?

Correct AnswerverifiedShow Answer

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