Question 1

Explain the similarities and differences between direct and indirect methods of measuring microbial growth and give examples of each.

Accepted Answer

Direct methods of measuring microbial gr...

Question 2

Which of the following is NOT a direct method for measuring the number of microbes in a sample?

Accepted Answer

A)   turbidity
B)   Coulter counter
C)   viable plate counts
D)   MPN
E)   membrane filtration

Question 3

A microbe that grows only slightly below the surface of a tube of thioglycolate medium is probably a(n)

Accepted Answer

A)   aerotolerant anaerobe.
B)   obligate anaerobe.
C)   facultative anaerobe.
D)   obligate aerobe.
E)   microaerophile.

Question 4

Nitrogen

Accepted Answer

A)   is a growth- limiting nutrient for many organisms.
B)   is used to build proteins and carbohydrates.
C)   is extracted from the atmosphere by a few types of bacteria.
D)   Both A and C are correct.
E)   A, B, and C are correct.

Question 5

Thermoduric mesophiles are often responsible for spoilage of improperly canned foods.

Accepted Answer

A) True 
 B)False

Question 6

Quorum sensing is a process by which bacteria respond to the density of other bacteria in their environment.

Accepted Answer

A) True 
 B)False

Question 7

During which growth phase are bacteria more susceptible to antimicrobial drugs?

Accepted Answer

A)   lag phase
B)   death phase
C)   log phase
D)   stationary phase
E)   The susceptibility is the same in all phases.

Question 8

Microbes that grow best at a pH of 6.5 to 7.5 are called _ .

Accepted Answer

The answer of Microbes that grow best at a pH...

Question 9

Joan wants to discover a microbe capable of degrading an environmental contaminant. Which of the following refers to the process she should use?

Accepted Answer

A)   quorum sensing
B)   enrichment culture
C)   nitrogen fixation
D)   lyophilization
E)   binary fission

Question 10

A fastidious organism might be grown on which of the following types of media?

Accepted Answer

A)   reducing media
B)   differential media
C)   transport media
D)   selective media
E)   enriched media

Question 11

At which of the following temperatures would a psychrophile grow best?

Accepted Answer

A)   20°C
B)   40°C
C)   30°C
D)   50°C
E)   10°C

Question 12

The radical is formed during the incomplete reduction of O2 by electron transport in aerobes.

Accepted Answer

The answer of The radical is formed during the incomplete...

Question 13

A colony- forming unit is the number of cells

Accepted Answer

A)   that are in exponential phase in a culture.
B)   that can be placed on a Petri plate.
C)   in a particular specimen.
D)   that produces one colony.
E)   in a colony.

Question 14

A microbiologist inoculates a growth medium with 1,000 bacterial cells/ml. If the generation time of the species is 30 minutes, how long will it be before the culture contains more than 10,000 cells/ml?

Accepted Answer

A)   3 hours
B)   1 hour
C)   5 hours
D)   3.5 hours
E)   2 hours

Question 15

Which of the following elements is never a limiting nutrient in cells?

Accepted Answer

A)   oxygen
B)   carbon
C)   nitrogen
D)   sulfur
E)   hydrogen

Question 16

Which of the following organisms would be most likely to contaminate a jar of pickles?

Accepted Answer

A)   an acidophile
B)   a neutrophile
C)   a mesophile
D)   a thermophile
E)   an obligate anaerobe

Question 17

Tap water is used sometimes to prepare growth media in the laboratory because

Accepted Answer

A)   it helps regulate osmotic pressure.
B)   it provides microbes with important growth factors.
C)   it reacts with some of the toxic forms of oxygen.
D)   it equalizes the hydrostatic pressure of the culture.
E)   it provides microbes with the necessary trace elements.

Question 18

An obligate halophile will burst if placed in freshwater.

Accepted Answer

A) True 
 B)False

Question 19

All of the following ingredients might be found in complex media EXCEPT:

Accepted Answer

A)   soy extract.
B)   blood.
C)   hydrogen peroxide.
D)   yeast extract.
E)   milk proteins.

Question 20

A(n) _ is a sample of microorganisms introduced into a growth medium.

Accepted Answer

The answer of A(n) _ is a sample of microorganisms...

Exam 6: Microbial Nutrition and Growth

A fastidious organism might be grown on which of the following types of media?

Correct AnswerverifiedShow Answer

Tap water is used sometimes to prepare growth media in the laboratory because

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Which of the following organisms would be most likely to contaminate a jar of pickles?

Correct AnswerverifiedShow Answer

Joan wants to discover a microbe capable of degrading an environmental contaminant. Which of the following refers to the process she should use?

Correct AnswerverifiedShow Answer

Quorum sensing is a process by which bacteria respond to the density of other bacteria in their environment.

Correct AnswerverifiedShow Answer

Thermoduric mesophiles are often responsible for spoilage of improperly canned foods.

Correct AnswerverifiedShow Answer

During which growth phase are bacteria more susceptible to antimicrobial drugs?

Correct AnswerverifiedShow Answer

An obligate halophile will burst if placed in freshwater.

Correct AnswerverifiedShow Answer

Explain the similarities and differences between direct and indirect methods of measuring microbial growth and give examples of each.

Correct AnswerverifiedDirect methods of measuring microbial gr...View AnswerShow Answer

All of the following ingredients might be found in complex media EXCEPT:

Correct AnswerverifiedShow Answer

A colony- forming unit is the number of cells

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A microbiologist inoculates a growth medium with 1,000 bacterial cells/ml. If the generation time of the species is 30 minutes, how long will it be before the culture contains more than 10,000 cells/ml?

Correct AnswerverifiedShow Answer

The radical is formed during the incomplete reduction of O2 by electron transport in aerobes.

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Microbes that grow best at a pH of 6.5 to 7.5 are called _ .

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Which of the following elements is never a limiting nutrient in cells?

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Nitrogen

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At which of the following temperatures would a psychrophile grow best?

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A microbe that grows only slightly below the surface of a tube of thioglycolate medium is probably a(n)

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A(n) _ is a sample of microorganisms introduced into a growth medium.

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Which of the following is NOT a direct method for measuring the number of microbes in a sample?

Correct AnswerverifiedShow Answer

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Direct methods of measuring microbial gr...
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