Question 1

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is

Accepted Answer

A)   disinfection.
B)   sterilization.
C)   antisepsis.
D)   sanitization.

Question 2

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

Accepted Answer

A) True 
 B)False

Question 3

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

Accepted Answer

A)   superoxide anion
B)   hydrogen peroxide
C)   hydroxyl radical
D)   Superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic.

Question 4

Which of these statements is/are TRUE?

Accepted Answer

A)   In general, species that can grow at higher temperatures are prokaryotic.
B)   The most thermophilic prokaryotes are species of Archaea.
C)   Chemoorganotrophic organisms are able to grow at higher temperatures than phototrophic organisms.
D)   All of the statements are true.

Question 5

Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique because it does not become inactivated at high temperatures.

Accepted Answer

A) True 
 B)False

Question 6

A selective medium is used to suppress the growth of certain bacteria in order to facilitate the growth of other bacteria.

Accepted Answer

A) True 
 B)False

Question 7

When attempting to determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method should be avoided?

Accepted Answer

A)   spread-plate method
B)   pour-plate method
C)   live staining and direct counting with a microscope
D)   both spread- and pour-plate methods

Question 8

Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles?

Accepted Answer

A)   decreased alpha helix content
B)   decreased beta sheet content
C)   fewer hydrogen bonds
D)   fewer ionic bonds

Question 9

Knowing the concentration of microorganisms in a sample is often an important consideration for environmental, industrial, and medical microbiologists, yet a microscope is sometimes not used to accomplish this task. Explain five major limitations to using a light microscope to directly count microorganisms.

Accepted Answer

All of the following eight are potential...

Question 10

Turbidity measurements are commonly utilized for monitoring

Accepted Answer

A)   planktonic cultures.
B)   biofilms.
C)   conies.
D)   sessile cultures. A

Question 11

Discuss the pros and cons of using radiation to sterilize items such as foods, drugs, and surgical supplies.

Accepted Answer

UV radiation sterilizes only the surfaces of objects which can be problematic for foods that are not fully cooked on the inside. Ionizing radiation can penetrate so they are ideal for foods such as grain cereals and ground beef. The high costs associated with the specialized equipment make it feasible only for large industrial applications. Due to the high energy of some of these radiation procedures, there are many concerns of potential radioactive contamination, production of carcinogenic or toxic products, and nutritional value alteration.

Question 12

Cell density in a chemostat is controlled by

Accepted Answer

A)   the concentration of the limiting nutrient.
B)   the dilution factor.
C)   the size of the initial inoculum.
D)   the concentration of the limiting nutrient, the dilution factor, and the size of the initial inoculum.

Question 13

A bacterial cell in nutrient broth with a generation time of 15 minutes will produce 16 cells in 2 hours.

Accepted Answer

A) True 
 B)False

Question 14

Describe the autoclave, and explain the roles of time, temperature, and pressure in the functioning of the autoclave.

Accepted Answer

High pressure is used in an autoclave so...

Question 15

A halotolerant facultative anaerobe would grow BEST in which of the following environments?

Accepted Answer

A)   oxygen depleted saline
B)   oxygenated saline
C)   oxygen depleted non-saline
D)   oxygenated non-saline D

Question 16

Which of the following methods used to enumerate cells often requires specialized staining to observe non-pigmented bacteria?

Accepted Answer

A)   spectrophotometry/turbidity
B)   spread-plating
C)   microscopy
D)   spread-plating, turbidity, and microscopy

Question 17

Which term is most relevant in describing the efficacy of an antimicrobial for use in a clinical setting?

Accepted Answer

A)   effective dose
B)   sterilization coefficient
C)   lethal dosage
D)   minimum inhibitory concentration (MI
C)

Question 18

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

Accepted Answer

The general theme should be on how lab c...

Question 19

The cell membranes of thermophiles and hyperthermophilic bacteria typically have

Accepted Answer

A)   more saturated fatty acids.
B)   more long chain fatty acids.
C)   fewer unsaturated fatty acids.
D)   All of these answer choices are true of thermophiles and hyperthermophilic bacteria.

Question 20

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

Accepted Answer

A) True 
 B)False

Exam 5: Microbial Growth and Its Control

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

Which of these statements is/are TRUE?

Correct Answer
verified

Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique because it does not become inactivated at high temperatures.

Correct Answer
verified

A selective medium is used to suppress the growth of certain bacteria in order to facilitate the growth of other bacteria.

Correct Answer
verified

When attempting to determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method should be avoided?

Correct Answer
verified

Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles?

Correct Answer
verified

Correct Answer
verified
All of the following eight are potential...
View Answer

Turbidity measurements are commonly utilized for monitoring

Correct Answer
verified
A

Discuss the pros and cons of using radiation to sterilize items such as foods, drugs, and surgical supplies.

Cell density in a chemostat is controlled by

Correct Answer
verified

A bacterial cell in nutrient broth with a generation time of 15 minutes will produce 16 cells in 2 hours.

Correct Answer
verified

Describe the autoclave, and explain the roles of time, temperature, and pressure in the functioning of the autoclave.

Correct Answer
verified
High pressure is used in an autoclave so...
View Answer

A halotolerant facultative anaerobe would grow BEST in which of the following environments?

Correct Answer
verified
D

Which of the following methods used to enumerate cells often requires specialized staining to observe non-pigmented bacteria?

Correct Answer
verified

Which term is most relevant in describing the efficacy of an antimicrobial for use in a clinical setting?

Correct Answer
verified

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

Correct Answer
verified
The general theme should be on how lab c...
View Answer

The cell membranes of thermophiles and hyperthermophilic bacteria typically have

Correct Answer
verified

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

Correct Answer
verified

Exam 5: Microbial Growth and Its Control

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which of these statements is/are TRUE?

Correct AnswerverifiedShow Answer

Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique because it does not become inactivated at high temperatures.

Correct AnswerverifiedShow Answer

A selective medium is used to suppress the growth of certain bacteria in order to facilitate the growth of other bacteria.

Correct AnswerverifiedShow Answer

When attempting to determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method should be avoided?

Correct AnswerverifiedShow Answer

Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedAll of the following eight are potential...View AnswerShow Answer

Turbidity measurements are commonly utilized for monitoring

Correct AnswerverifiedA

Discuss the pros and cons of using radiation to sterilize items such as foods, drugs, and surgical supplies.

Cell density in a chemostat is controlled by

Correct AnswerverifiedShow Answer

A bacterial cell in nutrient broth with a generation time of 15 minutes will produce 16 cells in 2 hours.

Correct AnswerverifiedShow Answer

Describe the autoclave, and explain the roles of time, temperature, and pressure in the functioning of the autoclave.

Correct AnswerverifiedHigh pressure is used in an autoclave so...View AnswerShow Answer

A halotolerant facultative anaerobe would grow BEST in which of the following environments?

Correct AnswerverifiedD

Which of the following methods used to enumerate cells often requires specialized staining to observe non-pigmented bacteria?

Correct AnswerverifiedShow Answer

Which term is most relevant in describing the efficacy of an antimicrobial for use in a clinical setting?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedThe general theme should be on how lab c...View AnswerShow Answer

The cell membranes of thermophiles and hyperthermophilic bacteria typically have

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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All of the following eight are potential...
View Answer

Correct Answer
verified
A

Correct Answer
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Correct Answer
verified

Correct Answer
verified
High pressure is used in an autoclave so...
View Answer

Correct Answer
verified
D

Correct Answer
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Correct Answer
verified
The general theme should be on how lab c...
View Answer

Correct Answer
verified

Correct Answer
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