Chapter 13: Sterilization, Disinfection, and Antibiotic Therapy
MULTIPLE CHOICE
1. In which of the following mechanisms of microbial control might some pathogens still survive?
a. sanitization c. disinfection
b. antisepsis d. sterilization
ANS: A DIF: Moderate REF: 13.1
OBJ: 13.1a Distinguish between sterilization, disinfection, antisepsis, and sanitation.
MSC: Understanding
2. Which of the following organisms is NOT killed by a germicidal agent?
a. bacteria c. fungi
b. virus d. endospore
ANS: D DIF: Easy REF: 13.1
OBJ: 13.1b Differentiate bacteriostatic agents from bactericidal agents.
MSC: Remembering
3. Hannibal Lecter, an infamous serial killer, is attempting to use H 2O2 to remove pesky blood stains of
his latest victim from his 100% cashmere scarf and for disinfection purposes. Why is it taking him so
long to disinfect his scarf?
a. H2O2 is not a good disinfection agent.
b. This type of disinfection procedure is best completed at colder temperatures.
c. Blood is an example of organic load that can inhibit the process of disinfection.
d. The organisms on his scarf are resistant to H2O2.
ANS: C DIF: Moderate REF: 13.1
OBJ: 13.1c Discuss decimal reduction time and its use in sterilizing material.
MSC: Applying
4. Which of the following terms can describe the death rate of microbial cells when exposed to an
antibacterial agent?
a. linear c. reverse logarithmic
b. exponential d. polar
ANS: B DIF: Moderate REF: 13.1
OBJ: 13.1c Discuss decimal reduction time and its use in sterilizing material.
MSC: Understanding
5. Standard conditions for sterilization by ________ are 121°C and 15 psi for 20 minutes.
a. autoclaving c. tyndallization
b. pasteurization d. lyophilization
ANS: A DIF: Easy REF: 13.2
OBJ: 13.2a Compare autoclave sterilization with pasteurization.
MSC: Understanding
, 6. 12D is the amount of time required to
a. kill 1012 spores. c. reduce the population by 1012.
b. kill 1012 cells. d. kill 90% of the population.
ANS: A DIF: Easy REF: 13.2
OBJ: 13.2a Compare autoclave sterilization with pasteurization.
MSC: Understanding
7. Glycerol is used to protect cells during
a. refrigeration. c. lyophilization.
b. deep-freezing. d. filtration.
ANS: B DIF: Moderate REF: 13.2
OBJ: 13.2b Explain the difference between refrigeration and lyophilization.
MSC: Applying
8. Which of the following is NOT a purpose of low temperatures in microbiology?
a. inhibit microbial growth c. kill microorganisms
b. stop microbial metabolism d. preserve microorganisms
ANS: C DIF: Moderate REF: 13.2
OBJ: 13.2b Explain the difference between refrigeration and lyophilization.
MSC: Understanding
9. Because it is an essential component for every individual, if enough vitamin C is not found in the diet,
supplements may be required. Vitamin C is sensitive to heat. So that it can be safe for human
consumption, how can vitamin C be sterilized before being packaged into supplements?
a. autoclave c. filtration
b. pasteurization d. lyophilization
ANS: C DIF: Moderate REF: 13.2
OBJ: 13.2c Describe the uses of filtration and laminar flow biological safety cabinets.
MSC: Applying
10. Which of the following does NOT affect the sensitivity of a microorganism to food irradiation?
a. genome size
b. rate of repair of DNA damage
c. whether the food is fresh or frozen
d. the presence of heat-shock enzymes
ANS: D DIF: Moderate REF: 13.2
OBJ: 13.2d List conditions in which irradiation can be used to sterilize.
MSC: Applying
11. Which of the following is NOT a factor affecting the efficacy of a disinfectant?
a. the barometric pressure
b. the presence of blood
c. the presence of endospore-forming bacteria
d. the corrosiveness of the disinfectant
ANS: A DIF: Moderate REF: 13.3
MULTIPLE CHOICE
1. In which of the following mechanisms of microbial control might some pathogens still survive?
a. sanitization c. disinfection
b. antisepsis d. sterilization
ANS: A DIF: Moderate REF: 13.1
OBJ: 13.1a Distinguish between sterilization, disinfection, antisepsis, and sanitation.
MSC: Understanding
2. Which of the following organisms is NOT killed by a germicidal agent?
a. bacteria c. fungi
b. virus d. endospore
ANS: D DIF: Easy REF: 13.1
OBJ: 13.1b Differentiate bacteriostatic agents from bactericidal agents.
MSC: Remembering
3. Hannibal Lecter, an infamous serial killer, is attempting to use H 2O2 to remove pesky blood stains of
his latest victim from his 100% cashmere scarf and for disinfection purposes. Why is it taking him so
long to disinfect his scarf?
a. H2O2 is not a good disinfection agent.
b. This type of disinfection procedure is best completed at colder temperatures.
c. Blood is an example of organic load that can inhibit the process of disinfection.
d. The organisms on his scarf are resistant to H2O2.
ANS: C DIF: Moderate REF: 13.1
OBJ: 13.1c Discuss decimal reduction time and its use in sterilizing material.
MSC: Applying
4. Which of the following terms can describe the death rate of microbial cells when exposed to an
antibacterial agent?
a. linear c. reverse logarithmic
b. exponential d. polar
ANS: B DIF: Moderate REF: 13.1
OBJ: 13.1c Discuss decimal reduction time and its use in sterilizing material.
MSC: Understanding
5. Standard conditions for sterilization by ________ are 121°C and 15 psi for 20 minutes.
a. autoclaving c. tyndallization
b. pasteurization d. lyophilization
ANS: A DIF: Easy REF: 13.2
OBJ: 13.2a Compare autoclave sterilization with pasteurization.
MSC: Understanding
, 6. 12D is the amount of time required to
a. kill 1012 spores. c. reduce the population by 1012.
b. kill 1012 cells. d. kill 90% of the population.
ANS: A DIF: Easy REF: 13.2
OBJ: 13.2a Compare autoclave sterilization with pasteurization.
MSC: Understanding
7. Glycerol is used to protect cells during
a. refrigeration. c. lyophilization.
b. deep-freezing. d. filtration.
ANS: B DIF: Moderate REF: 13.2
OBJ: 13.2b Explain the difference between refrigeration and lyophilization.
MSC: Applying
8. Which of the following is NOT a purpose of low temperatures in microbiology?
a. inhibit microbial growth c. kill microorganisms
b. stop microbial metabolism d. preserve microorganisms
ANS: C DIF: Moderate REF: 13.2
OBJ: 13.2b Explain the difference between refrigeration and lyophilization.
MSC: Understanding
9. Because it is an essential component for every individual, if enough vitamin C is not found in the diet,
supplements may be required. Vitamin C is sensitive to heat. So that it can be safe for human
consumption, how can vitamin C be sterilized before being packaged into supplements?
a. autoclave c. filtration
b. pasteurization d. lyophilization
ANS: C DIF: Moderate REF: 13.2
OBJ: 13.2c Describe the uses of filtration and laminar flow biological safety cabinets.
MSC: Applying
10. Which of the following does NOT affect the sensitivity of a microorganism to food irradiation?
a. genome size
b. rate of repair of DNA damage
c. whether the food is fresh or frozen
d. the presence of heat-shock enzymes
ANS: D DIF: Moderate REF: 13.2
OBJ: 13.2d List conditions in which irradiation can be used to sterilize.
MSC: Applying
11. Which of the following is NOT a factor affecting the efficacy of a disinfectant?
a. the barometric pressure
b. the presence of blood
c. the presence of endospore-forming bacteria
d. the corrosiveness of the disinfectant
ANS: A DIF: Moderate REF: 13.3
