Question 1

Oxidizing agents include all of the following EXCEPT

Accepted Answer

A)  ozone. 
B)  hydrogen peroxide. 
C)  chlorine. 
D)  glutaraldehyde. 
E)  iodine. 
A)  ozone. 
B)  hydrogen peroxide. 
C)  chlorine. 
D)  glutaraldehyde. 
E)  iodine. D

Question 2

Which of the following treatments is the most effective for controlling microbial growth?

Accepted Answer

A)  63°C for 30 minutes 
B)  72°C for 15 seconds 
C)  140°C for 4 seconds 
D)  They are equivalent treatments. 
E)  None of the answers is correct. 
A)  63°C for 30 minutes 
B)  72°C for 15 seconds 
C)  140°C for 4 seconds 
D)  They are equivalent treatments. 
E)  None of the answers is correct. D

Question 3

Which of the following does NOT achieve sterilization?

Accepted Answer

A)  supercritical fluids 
B)  dry heat 
C)  ethylene oxide 
D)  pasteurization 
E)  autoclave 
A)  supercritical fluids 
B)  dry heat 
C)  ethylene oxide 
D)  pasteurization 
E)  autoclave D

Question 4

Ethylene oxide

Accepted Answer

A)  requires high heat to be effective. 
B)  is the active chemical in household bleach. 
C)  is a sterilizing agent. 
D)  is a good antiseptic. 
E)  is not sporicidal. 
A)  requires high heat to be effective. 
B)  is the active chemical in household bleach. 
C)  is a sterilizing agent. 
D)  is a good antiseptic. 
E)  is not sporicidal.

Question 5

Which of the following best describes the pattern of microbial death?

Accepted Answer

A)  All the cells in a culture die at once. 
B)  The cells in a population die at a constant rate. 
C)  The pattern varies depending on the species. 
D)  The pattern varies depending on the antimicrobial agent. 
E)  Not all of the cells in a culture are killed. 
A)  All the cells in a culture die at once. 
B)  The cells in a population die at a constant rate. 
C)  The pattern varies depending on the species. 
D)  The pattern varies depending on the antimicrobial agent. 
E)  Not all of the cells in a culture are killed.

Question 6

All of the following are methods of food preservation EXCEPT

Accepted Answer

A)  osmotic pressure. 
B)  microwaves. 
C)  high pressure. 
D)  ionizing radiation. 
E)  desiccation. 
A)  osmotic pressure. 
B)  microwaves. 
C)  high pressure. 
D)  ionizing radiation. 
E)  desiccation.

Question 7

Figure 7.2
Assume 10S1U1P19 S1S1P0E. coli cells/ml are in a flask.
  
-Which graph in Figure 7.2 best depicts the effect of placing the culture at 7°C at time x?

Accepted Answer

A)  a 
B)  b 
C)  c 
D)  d 
E)  e 
A)  a 
B)  b 
C)  c 
D)  d 
E)  e

Question 8

Table 7.4
The results below were obtained from a use- dilution test of two disinfectants.
Cultures were inoculated into tubes with varying concentrations of disinfectants
and incubated for 24 hr at 20°C, then subcultured in nutrient media without disinfectants. (+ = growth; - = no growth)
  
-In Table 7.4, what is the minimal bacteriostatic concentration of each disinfectant? Which compound is bactericidal? At what concentration?

Accepted Answer

Without the actual data from Table 7.4,

Question 9

All of the following factors contribute to hospital- acquired infections EXCEPT

Accepted Answer

A)  some bacteria metabolize disinfectants. 
B)  bacteria may be present in commercial products such as mouthwash. 
C)  invasive procedures can provide a portal of entry for bacteria. 
D)  gram- negative bacteria are often resistant to disinfectants. 
E)  None of the answers is correct; all of these factors may contribute to hospital- acquired infection. 
A)  some bacteria metabolize disinfectants. 
B)  bacteria may be present in commercial products such as mouthwash. 
C)  invasive procedures can provide a portal of entry for bacteria. 
D)  gram- negative bacteria are often resistant to disinfectants. 
E)  None of the answers is correct; all of these factors may contribute to hospital- acquired infection.

Question 10

Desiccation is a reliable form of sterilization.

Accepted Answer

A) True 
 B)False

Question 11

All of the following are effective for destroying prions EXCEPT

Accepted Answer

A)  NaOH + autoclaving at 134°C. 
B)  incineration. 
C)  proteases. 
D)  boiling. 
E)  None of the answers are correct; each of these will destroy prions. 
A)  NaOH + autoclaving at 134°C. 
B)  incineration. 
C)  proteases. 
D)  boiling. 
E)  None of the answers are correct; each of these will destroy prions.

Question 12

Which of the following is the best method to sterilize heat- labile solutions?

Accepted Answer

A)  freezing 
B)  membrane filtration 
C)  dry heat 
D)  pasteurization 
E)  autoclave 
A)  freezing 
B)  membrane filtration 
C)  dry heat 
D)  pasteurization 
E)  autoclave

Question 13

Which of the following pairs is mismatched?

Accepted Answer

A)  alcohols - open wounds 
B)  H2O2 - open wounds 
C)  CuSO4 - algicide 
D)  organic acids - food preservation 
E)  Ag - wound dressings 
A)  alcohols - open wounds 
B)  H2O2 - open wounds 
C)  CuSO4 - algicide 
D)  organic acids - food preservation 
E)  Ag - wound dressings

Question 14

Which concentration of ethanol is the most effective bactericide?

Accepted Answer

A)  100 percent 
B)  70 percent 
C)  50 percent 
D)  40 percent 
E)  30 percent 
A)  100 percent 
B)  70 percent 
C)  50 percent 
D)  40 percent 
E)  30 percent

Question 15

Figure 7.1
A suspension of 10S1U1P16S1S1P0S1U1P1 S1S1P0Bacillus cereus endospores was put in a hot- air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown.
  
-In Figure 7.1, what is the thermal death time?

Accepted Answer

A)  120 minutes 
B)  100°C 
C)  60 minutes 
D)  150°C 
E)  The answer cannot be determined based on the information provided. 
A)  120 minutes 
B)  100°C 
C)  60 minutes 
D)  150°C 
E)  The answer cannot be determined based on the information provided.

Question 16

Figure 7.2
Assume 10S1U1P19 S1S1P0E. coli cells/ml are in a flask.
  
-Which graph in Figure 7.2 best depicts the effect of placing the culture in an autoclave for 15 minutes at time x?

Accepted Answer

A)  a 
B)  b 
C)  c 
D)  d 
E)  e 
A)  a 
B)  b 
C)  c 
D)  d 
E)  e

Question 17

Figure 7.1
A suspension of 10S1U1P16S1S1P0S1U1P1 S1S1P0Bacillus cereus endospores was put in a hot- air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown.
  
-In Figure 7.1, the thermal death point for this culture is

Accepted Answer

A)  15 minutes. 
B)  50°C. 
C)  170°C. 
D)  30 minutes. 
E)  The answer cannot be determined based on the information provided 
A)  15 minutes. 
B)  50°C. 
C)  170°C. 
D)  30 minutes. 
E)  The answer cannot be determined based on the information provided

Question 18

Application of heat to living cells can result in all of the following EXCEPT

Accepted Answer

A)  alteration of membrane permeability. 
B)  breaking of hydrogen bonds. 
C)  denaturation of enzymes. 
D)  damage to nucleic acids. 
E)  decreased thermal death time. 
A)  alteration of membrane permeability. 
B)  breaking of hydrogen bonds. 
C)  denaturation of enzymes. 
D)  damage to nucleic acids. 
E)  decreased thermal death time.

Question 19

Which of the following disinfectants acts by disrupting the plasma membrane?

Accepted Answer

A)  heavy metals 
B)  soaps 
C)  bisphenols 
D)  halogens 
E)  aldehydes 
A)  heavy metals 
B)  soaps 
C)  bisphenols 
D)  halogens 
E)  aldehydes

Question 20

An iodophor is a(n)

Accepted Answer

A)  agent that reduces oxygen. 
B)  form of formaldehyde. 
C)  phenol. 
D)  iodine mixed with a surfactant. 
E)  quaternary ammonium compound. 
A)  agent that reduces oxygen. 
B)  form of formaldehyde. 
C)  phenol. 
D)  iodine mixed with a surfactant. 
E)  quaternary ammonium compound.

Exam 7: The Control of Microbial Growth

Oxidizing agents include all of the following EXCEPT

Which of the following treatments is the most effective for controlling microbial growth?

Which of the following does NOT achieve sterilization?

Ethylene oxide

Which of the following best describes the pattern of microbial death?

All of the following are methods of food preservation EXCEPT

Figure 7.2 Assume 109 E. coli cells/ml are in a flask. -Which graph in Figure 7.2 best depicts the effect of placing the culture at 7°C at time x?

All of the following factors contribute to hospital- acquired infections EXCEPT

Desiccation is a reliable form of sterilization.

All of the following are effective for destroying prions EXCEPT

Which of the following is the best method to sterilize heat- labile solutions?

Which of the following pairs is mismatched?

Which concentration of ethanol is the most effective bactericide?

Figure 7.1 A suspension of 106 Bacillus cereus endospores was put in a hot- air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown. -In Figure 7.1, what is the thermal death time?

Figure 7.2 Assume 109 E. coli cells/ml are in a flask. -Which graph in Figure 7.2 best depicts the effect of placing the culture in an autoclave for 15 minutes at time x?

Figure 7.1 A suspension of 106 Bacillus cereus endospores was put in a hot- air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown. -In Figure 7.1, the thermal death point for this culture is

Application of heat to living cells can result in all of the following EXCEPT

Which of the following disinfectants acts by disrupting the plasma membrane?

An iodophor is a(n)

The Microbial World and You

Chemical Principles

Observing Microorganisms Through a Microscope

Functional Anatomy of Prokaryotic and Eukaryotic Cells

Microbial Metabolism

Microbial Growth

Microbial Genetics

Biotechnology and Recombinant Dna

Classification of Microorganisms

The Prokaryotes: Domains Bacteria and Archaea

The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

Viruses, Viroids, and Prions

Principles of Disease and Epidemiology

Microbial Mechanisms of Pathogenicity

Innate Immunity: Nonspecific Defenses of the Host

Adaptive Immunity: Specific Defenses of the Host

Practical Applications of Immunology

Disorders Associated With the Immune System

Antimicrobial Drugs

Microbial Diseases of the Skin and Eyes

Microbial Diseases of the Nervous System

Microbial Diseases of the Cardiovascular and Lymphatic Systems

Microbial Diseases of the Respiratory System

Microbial Diseases of the Digestive System

Microbial Diseases of the Urinary and Reproductive Systems

Environmental Microbiology

Applied and Industrial Microbiology

Filters

Figure 7.2 Assume 10⁹E. coli cells/ml are in a flask. -Which graph in Figure 7.2 best depicts the effect of placing the culture at 7°C at time x?

Figure 7.1 A suspension of 10⁶Bacillus cereus endospores was put in a hot- air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown. -In Figure 7.1, what is the thermal death time?

Figure 7.2 Assume 10⁹E. coli cells/ml are in a flask. -Which graph in Figure 7.2 best depicts the effect of placing the culture in an autoclave for 15 minutes at time x?

Figure 7.1 A suspension of 10⁶Bacillus cereus endospores was put in a hot- air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown. -In Figure 7.1, the thermal death point for this culture is