Question 1

Which temperature is lethal to any mesophile?

Accepted Answer

A)  its optimum growth temperature 
B)  its minimum growth temperature 
C)  its maximum growth temperature 
D)  refrigeration temperature 
E)  autoclave temperature 
A)  its optimum growth temperature 
B)  its minimum growth temperature 
C)  its maximum growth temperature 
D)  refrigeration temperature 
E)  autoclave temperature E

Question 2

Why is death a logarithmic function and not an instantaneous event upon treatment?

Accepted Answer

For one thing, all cells in a population may not be at the same level of fitness. Some cells may be more susceptible than others. Another aspect is the probability of the treatment causing a lethal hit. Cells contain many different proteins and genes. Hits to one may not be as deleterious as to another. Moreover, damage must accumulate. Only after enough molecules of an essential gene or protein have been affected in a cell will it die. For these reasons, the entire population does not die immediately upon treatment; instead, it will have an exponential demise.

Question 3

Which of the following enzymes are stable in part because they contain relatively low amounts of the small amino acid glycine?

Accepted Answer

A)  psychrophilic 
B)  acidophilic 
C)  thermophilic 
D)  halophilic 
E)  barophilic 
A)  psychrophilic 
B)  acidophilic 
C)  thermophilic 
D)  halophilic 
E)  barophilic C

Question 4

Organisms that grow at temperatures as high as 121°C as well as high pressure are known as

Accepted Answer

A)  thermophiles. 
B)  extreme halophiles. 
C)  psychrophiles. 
D)  hyperpsychrophiles. 
E)  hyperthermophiles. 
A)  thermophiles. 
B)  extreme halophiles. 
C)  psychrophiles. 
D)  hyperpsychrophiles. 
E)  hyperthermophiles.

Question 5

Briefly describe three techniques used to culture anaerobes in the laboratory.

Accepted Answer

Liquid media that contain reducing agent

Question 6

If you have a food sample contaminated with anthrax spores, which sterilization approach would make sure the sample is free of spores without compromising the quality of the food sample-autoclaving or irradiation? Why?

Accepted Answer

Although both autoclaving and irradiatio

Question 7

Which of the following have evolved to grow in conditions extremely different from those optimal for humans?

Accepted Answer

A)  psychrophiles 
B)  extremophiles 
C)  halophiles 
D)  thermophiles 
E)  acidophiles 
A)  psychrophiles 
B)  extremophiles 
C)  halophiles 
D)  thermophiles 
E)  acidophiles

Question 8

An organism that requires atmospheric oxygen levels for growth is

Accepted Answer

A)  aerobic. 
B)  microaerophilic. 
C)  aerotolerant. 
D)  anaerobic. 
E)  facultative. 
A)  aerobic. 
B)  microaerophilic. 
C)  aerotolerant. 
D)  anaerobic. 
E)  facultative.

Question 9

An organism that grows in the circled region of the tube of medium containing thioglycolate shown below is probably a(n)

Accepted Answer

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

Question 10

A measure of the number of solute molecules in solution and is inversely related to water activity is known as

Accepted Answer

A)  osmolarity. 
B)  hypertonic. 
C)  hypotonic. 
D)  isotonic. 
E)  d-value. 
A)  osmolarity. 
B)  hypertonic. 
C)  hypotonic. 
D)  isotonic. 
E)  d-value.

Question 11

Alkaliphiles use ________ force in addition to proton motive force to maintain pH.

Accepted Answer

A)  potassium motive 
B)  sodium motive 
C)  calcium motive 
D)  magnesium motive 
E)  sulfur motive 
A)  potassium motive 
B)  sodium motive 
C)  calcium motive 
D)  magnesium motive 
E)  sulfur motive

Question 12

Filtration of samples to remove microbial cells typically use micropore filters with pore sizes of

Accepted Answer

A)  1.5 mm. 
B)  0.20 mm. 
C)  0.1 nm. 
D)  150 mm. 
E)  0.2 mm. 
A)  1.5 mm. 
B)  0.20 mm. 
C)  0.1 nm. 
D)  150 mm. 
E)  0.2 mm.

Question 13

An organism that grows at the top of a tube of medium containing thioglycolate is probably a(n)

Accepted Answer

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

Question 14

Which category best describes E. coli?

Accepted Answer

A)  strict aerobe 
B)  aerotolerant anaerobe 
C)  facultative anaerobe 
D)  microaerophile 
E)  strict anaerobe 
A)  strict aerobe 
B)  aerotolerant anaerobe 
C)  facultative anaerobe 
D)  microaerophile 
E)  strict anaerobe

Question 15

Halophiles require high salt concentrations to survive. Describe a mechanism involving compatible solutes that has evolved to achieve low internal sodium ion concentrations.

Accepted Answer

Cells have symporter systems that will i

Question 16

No one ever expected to find microbes thriving in our stomachs. What organism was found there, what problem does it cause, and how does it survive there?

Accepted Answer

The bacterium Helicobacter pylori thrive

Question 17

Why do some microorganisms produce antibiotics, and how do they avoid being harmed by the antibiotics they produce?

Accepted Answer

Answers will vary. Microbes make antibio

Question 18

How is the phenol coefficient calculated? Why is phenol the standard for testing other disinfectants?

Accepted Answer

Because of its potency and its history,

Question 19

If a disinfectant is added to a culture containing 1 * 10⁶ CFU per milliliter and the D-value of the disinfectant is 2 minutes, how many viable cells are left after 4 minutes of exposure?

Accepted Answer

The D-value is the time required to kill

Question 20

Deinococcus radiodurans resists extreme drought and radiation by what mechanism?

Accepted Answer

A)  biofilm formation 
B)  producing aquaporins 
C)  producing multidrug efflux pumps 
D)  endospore formation 
E)  repairing DNA damage 
A)  biofilm formation 
B)  producing aquaporins 
C)  producing multidrug efflux pumps 
D)  endospore formation 
E)  repairing DNA damage

Exam 5: Environmental Influences and Control of Microbial Growth

Which temperature is lethal to any mesophile?

Why is death a logarithmic function and not an instantaneous event upon treatment?

Which of the following enzymes are stable in part because they contain relatively low amounts of the small amino acid glycine?

Organisms that grow at temperatures as high as 121°C as well as high pressure are known as

Briefly describe three techniques used to culture anaerobes in the laboratory.

If you have a food sample contaminated with anthrax spores, which sterilization approach would make sure the sample is free of spores without compromising the quality of the food sample-autoclaving or irradiation? Why?

Which of the following have evolved to grow in conditions extremely different from those optimal for humans?

An organism that requires atmospheric oxygen levels for growth is

An organism that grows in the circled region of the tube of medium containing thioglycolate shown below is probably a(n)

A measure of the number of solute molecules in solution and is inversely related to water activity is known as

Alkaliphiles use ________ force in addition to proton motive force to maintain pH.

Filtration of samples to remove microbial cells typically use micropore filters with pore sizes of

An organism that grows at the top of a tube of medium containing thioglycolate is probably a(n)

Which category best describes E. coli?

Halophiles require high salt concentrations to survive. Describe a mechanism involving compatible solutes that has evolved to achieve low internal sodium ion concentrations.

No one ever expected to find microbes thriving in our stomachs. What organism was found there, what problem does it cause, and how does it survive there?

Why do some microorganisms produce antibiotics, and how do they avoid being harmed by the antibiotics they produce?

How is the phenol coefficient calculated? Why is phenol the standard for testing other disinfectants?

If a disinfectant is added to a culture containing 1 * 10⁶ CFU per milliliter and the D-value of the disinfectant is 2 minutes, how many viable cells are left after 4 minutes of exposure?

Deinococcus radiodurans resists extreme drought and radiation by what mechanism?

Microbial Life: Origin and Discovery

Observing the Microbial Cell

Cell Structure and Function

Bacterial Culture, Growth, and Development

Viruses

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Molecular Regulation

Viral Molecular Biology

Biotechniques and Synthetic Biology

Energetics and Catabolism

Electron Flow in Organotrophy, Lithotrophy, and Phototrophy

Biosynthesis

Food and Industrial Microbiology

Origins and Evolution

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes in Global Elemental Cycles

Human Microbiota and Innate Immunity

The Adaptive Immune Response

Microbial Pathogenesis

Microbial Diseases

Antimicrobial Therapy

Clinical Microbiology and Epidemiology

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