Question 1

Obligate anaerobes which are sensitive to O₂ would be found growing

Accepted Answer

A)  throughout a tube of thioglycolate broth. 
B)  only at the very top of a tube of thioglycolate broth. 
C)  only at the bottom of a tube of thioglycolate broth. 
D)  approximately one-third of the way down the thioglycolate broth. 
A)  throughout a tube of thioglycolate broth. 
B)  only at the very top of a tube of thioglycolate broth. 
C)  only at the bottom of a tube of thioglycolate broth. 
D)  approximately one-third of the way down the thioglycolate broth.

Question 2

A complex medium is one that has been completely made in the laboratory and the concentration of all the nutrients is known.

Accepted Answer

A) True 
 B)False

Question 3

The duration of exponential growth would increase if bacterial cells divided into three equal daughter cells rather than two.

Accepted Answer

A) True 
 B)False

Question 4

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

Accepted Answer

A)  generation time. 
B)  growth time. 
C)  growth rate. 
D)  division rate. 
A)  generation time. 
B)  growth time. 
C)  growth rate. 
D)  division rate.

Question 5

Which of the following statements is FALSE?

Accepted Answer

A)  In the death phase, bacterial growth may cease as a result of oxygen and nutrient depletion. 
B)  The generation time of bacteria may vary from species to species. 
C)  Bacteria typically divide by binary fission, producing two daughter cells. 
D)  In the lag phase, cell death exceeds cell division. 
A)  In the death phase, bacterial growth may cease as a result of oxygen and nutrient depletion. 
B)  The generation time of bacteria may vary from species to species. 
C)  Bacteria typically divide by binary fission, producing two daughter cells. 
D)  In the lag phase, cell death exceeds cell division.

Question 6

A bacterium possessing ________ will produce O₂ bubbles when placed in the presence of hydrogen peroxide.

Accepted Answer

A)  catalase 
B)  superoxide dismutase 
C)  superoxide reductase 
D)  peroxidase 
A)  catalase 
B)  superoxide dismutase 
C)  superoxide reductase 
D)  peroxidase

Question 7

Why is the enzyme catalase important to the survival of bacteria?

Accepted Answer

A)  Catalase protects the cell from desiccation. 
B)  Catalase breaks down toxic hydrogen peroxide. 
C)  Catalase allows for growth in high salt concentrations. 
D)  Catalase aids in the transport of oxygen into the cell. 
A)  Catalase protects the cell from desiccation. 
B)  Catalase breaks down toxic hydrogen peroxide. 
C)  Catalase allows for growth in high salt concentrations. 
D)  Catalase aids in the transport of oxygen into the cell.

Question 8

Why is 100% ethanol less effective as an antimicrobial compared to a 70-95% concentration of ethanol?

Accepted Answer

70% percent alcohol is ideal as opposed

Question 9

Most microorganisms are particularly susceptible to antimicrobial agents during the logarithmic growth phase.

Accepted Answer

A) True 
 B)False

Question 10

The optimal growth temperature of a bacterium is most closely related to the optimal temperature for

Accepted Answer

A)  transcription of DNA. 
B)  DNA replication. 
C)  enzyme function. 
D)  mRNA attachment to ribosomes. 
A)  transcription of DNA. 
B)  DNA replication. 
C)  enzyme function. 
D)  mRNA attachment to ribosomes.

Question 11

Superoxide dismutase and catalase work together to convert superoxide into

Accepted Answer

A)  peroxide. 
B)  oxygen. 
C)  water 
D)  water and oxygen. 
A)  peroxide. 
B)  oxygen. 
C)  water 
D)  water and oxygen.

Question 12

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

Accepted Answer

A)  inoculum volume. 
B)  size of the colonies. 
C)  type of culture medium. 
D)  incubation time. 
A)  inoculum volume. 
B)  size of the colonies. 
C)  type of culture medium. 
D)  incubation time.

Question 13

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

Accepted Answer

A) True 
 B)False

Question 14

Refrigeration controls microbial growth in food as a result of irreversible cell damage caused by low temperature.

Accepted Answer

A) True 
 B)False

Question 15

When water activity is low, an organism must

Accepted Answer

A)  increase its internal solute concentration. 
B)  increase its external solute concentration. 
C)  decrease its internal solute concentration. 
D)  decrease its external solute concentration. 
A)  increase its internal solute concentration. 
B)  increase its external solute concentration. 
C)  decrease its internal solute concentration. 
D)  decrease its external solute concentration.

Question 16

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

Accepted Answer

A) True 
 B)False

Question 17

A ________ agent is a chemical that inhibits bacteria from reproducing, but does NOT necessarily kill them.

Accepted Answer

A)  bacteriostatic 
B)  bacteriolytic 
C)  bacteriocidal 
D)  xerophilic 
A)  bacteriostatic 
B)  bacteriolytic 
C)  bacteriocidal 
D)  xerophilic

Question 18

Microbial contamination is prevented by the

Accepted Answer

A)  use of the quadrant streak method. 
B)  use of aseptic technique. 
C)  use of cultures containing special nutrients. 
D)  spread plate method. 
A)  use of the quadrant streak method. 
B)  use of aseptic technique. 
C)  use of cultures containing special nutrients. 
D)  spread plate method.

Question 19

A bacterium whose optimal growth temperature is 35˚C would be classified as a thermophile.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following statements is TRUE of disinfectants?

Accepted Answer

A)  They are always effective in destroying endospores. 
B)  They are used on living tissue. 
C)  They are used for sterilization. 
D)  They are used on inanimate surfaces. 
A)  They are always effective in destroying endospores. 
B)  They are used on living tissue. 
C)  They are used for sterilization. 
D)  They are used on inanimate surfaces.

Exam 5: Microbial Growth and Its Control

Obligate anaerobes which are sensitive to O₂ would be found growing

A complex medium is one that has been completely made in the laboratory and the concentration of all the nutrients is known.

The duration of exponential growth would increase if bacterial cells divided into three equal daughter cells rather than two.

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

Which of the following statements is FALSE?

A bacterium possessing ________ will produce O₂ bubbles when placed in the presence of hydrogen peroxide.

Why is the enzyme catalase important to the survival of bacteria?

Why is 100% ethanol less effective as an antimicrobial compared to a 70-95% concentration of ethanol?

Most microorganisms are particularly susceptible to antimicrobial agents during the logarithmic growth phase.

The optimal growth temperature of a bacterium is most closely related to the optimal temperature for

Superoxide dismutase and catalase work together to convert superoxide into

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

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

Refrigeration controls microbial growth in food as a result of irreversible cell damage caused by low temperature.

When water activity is low, an organism must

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

A ________ agent is a chemical that inhibits bacteria from reproducing, but does NOT necessarily kill them.

Microbial contamination is prevented by the

A bacterium whose optimal growth temperature is 35˚C would be classified as a thermophile.

Which of the following statements is TRUE of disinfectants?

The Microbial World

Microbial Cell Structure and Function

Microbial Metabolism

Molecular Information Flow and Protein Processing

Microbial Regulatory Systems

Molecular Biology of Microbial Growth

Viruses and Their Replication

Microbial Systems Biology

Viral Genomics, Diversity, and Ecology

Genetics of Bacteria and Archaea

Biotechnology and Synthetic Biology

Microbial Evolution and Systematics

Metabolic Diversity of Microorganisms

Functional Diversity of Microorganisms

Diversity of Bacteria

Diversity of Archaea

Diversity of Microbial Eukarya

Taking the Measure of Microbial Systems

Microbial Ecosystems

Nutrient Cycles

Microbiology of the Built Environment

Microbial Symbioses

Microbial Symbioses with Humans

Microbial Infection and Pathogenesis

Innate Immunity: Broadly Specific Host Defenses

Adaptive Immunity: Highly Specific Host Defenses

Clinical Microbiology and Immunology

Epidemiology

Person-to-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

Waterborne and Foodborne Bacterial and Viral Diseases

Eukaryotic Pathogens: Fungi, Protozoans, and Helminths

Filters