Deck 12: Sterilization and Disinfection

Question 1

Soluble compounds that reduce surface tension thus dissolving lipids are known as:

A) alkylating agents
B) halogens
C) oxidizing agents
D) surfactants

Answer 1

D

Question 2

An agent that inhibits the growth of bacteria is called a (an)

A) antiseptic
B) bactericide
C) bacteriostatic
D) sanitizer

Answer 2

C

Question 3

Surfactants include all of the following except

A) alcohols
B) detergents
C) wetting agents
D) oxidizing agents

Answer 3

D

Question 4

A viricide is an agent that

A) inactivates viruses.
B) propagates viruses.
C) inhibits viruses and bacterial endospores.
D) allows viral multiplication.

Question 5

All of the following qualities apply to the selection of an ideal disinfectant except

A) fast acting
B) effective against all infective agents without harming host tissue
C) easily penetrating material without harming material
D) expensive and difficult to obtain and use

Question 6

Which is not used to measure the effectiveness of an antimicrobial agent?

A) filter paper method
B) phenol coefficient method
C) use-dilution method
D) plate count method

Question 7

All of the following pertain to the effectiveness of a chemical antimicrobial agent except

A) time
B) temperature
C) pH
D) combustibility

Question 8

Which is a cationic detergent having four organic groups attached to a nitrogen atom and used to sanitize utensils?

A) quaternary ammonium compound
B) propionic acid
C) methylene blue
D) ethylene oxide

Question 9

All of the following apply to the control of microbial growth except

A) a definite proportion of organisms die within a given time interval.
B) the fewer organisms present, the shorter the time needed for sterility.
C) microorganisms differ in their susceptibility to antimicrobial agents.
D) heat is not considered an antimicrobial agent.

Question 10

Chemical agents that denature proteins include all of the following except

A) acids
B) alkalis
C) detergents
D) halogens

Question 11

Which of the following do not affect viruses?

A) alkylating agents
B) detergents
C) alcohols
D) halogens

Question 12

Sterilization is the

A) killing or removal of all microorganisms in a material or an object.
B) reduction of the number of pathogenic microorganisms in a material or object.
C) killing or removal of some but not all microorganisms.
D) disinfection of living tissue.

Question 13

All of the following are examples of heavy metals used as antimicrobial agents except

A) iodine
B) merthiolate
C) selenium sulfate
D) copper sulfate

Question 14

An agent capable of killing microbes rapidly,perhaps killing certain microorganisms but only inhibiting the growth of others is called

A) antiseptic
B) disinfectant
C) sanitizer
D) germicide

Question 15

What is a chemical agent that can safely be used externally on living tissue to destroy microorganisms or to inhibit their growth?

A) antiseptic
B) disinfectant
C) sanitizer
D) germicide

Question 16

When an antimicrobial agent permanently denatures proteins thus preventing renaturation to their native states it is considered:

A) bacteriostatic
B) bactericidal
C) bacterial lysis
D) an inhibitor of growth

Question 17

Agents that adversely affect nucleic acids and energy production include all of the following except

A) detergents
B) alcohols
C) crystal violet
D) lactic acid

Question 18

The use of phenol as a standard with which to compare the effectiveness of other chemical disinfectants is referred to as the

A) phenol coefficient
B) phenol concentration
C) phenol effectiveness
D) phenol conditions

Question 19

Disinfection is the

A) killing of certain microorganisms while only inhibiting others.
B) killing or removal of all microorganisms in a material or an object.
C) same as sterilization.
D) reduction of the number of pathogenic microorganisms to pose no threat of disease.

Question 20

What is the most susceptible phase of growth for most microorganisms by an antimicrobial agent?

A) lag phase
B) log phase
C) stationary phase
D) death phase

Question 21

Which of the following statements about evaluating the effectiveness of chemical agents is false?

A) phenol coefficient can be used to evaluate the efficacy of phenol derivatives
B) materials present can complex with or inactivate a chemical agent during the phenol coefficient test
C) in the filter paper test, a clear area around the disk indicates a prevention of microorganism growth but not killing of microbes
D) the use-dilution test is considered to be more meaningful than the phenol coefficient

Question 22

Ultrahigh temperature (UHT)processing does not involve:

A) treating small containers of coffee creamer
B) using a complex cooling procedure
C) raising temperature from 74 °C to 140 °C and dropping it back to 74 °C within 5 seconds
D) presence of a "cooked" flavor in milk flavored with vanilla, strawberry or chocolate

Question 23

Ionizing radiation

A) consists of wavelengths between 400 and 390 nm
B) oxidizes molecules such as riboflavin and porphyrins
C) is tuned to match the energy levels of water molecules
D) dislodges electrons from atoms, creating ions

Question 24

Which of the following involves sterilization by heating steam in a jacket and subsequent entrance of the steam into a sterilization chamber,where materials and substances to be sterilized are placed:

A) autoclave
B) pasteurization chamber
C) dry heat oven
D) open flame

Question 25

Denaturation of proteins by antimicrobial agents

A) prevents viruses from infecting host cells
B) disrupts hydrogen and disulfide bonds
C) aids in preserving the shape and function of proteins
D) two of the above

Question 26

Alcohols

A) oxidize disulfide bonds
B) dissolve lipids and denature proteins
C) alter nucleic acids
D) lower the pH

Question 27

Which of the following are not examples of alkylating agents that disrupt proteins and nucleic acids?

A) glutaraldahyde
B) b-propiolactone
C) ethylene oxide
D) methylene oxide

Question 28

Which of the following chemical antimicrobial agents is matched correctly with its mechanism?

A) phenols disrupt cell membranes
B) alkyating agents block cell wall synthesis
C) acids lower surface tension
D) surfactants raise pH and denature proteins

Question 29

Lyophilization is

A) freeze-drying
B) refrigeration
C) freezing
D) heat-drying

Question 30

Which does not pertain to pasteurization?

A) can be done with ultrahigh temperatures
B) invented by Louis Pasteur
C) achieves sterility
D) destroys organisms that caused wine to sour

Question 31

Microwave radiation

A) damages DNA by ionizing radiation.
B) destroys bacterial endospores.
C) produces peroxides, which oxidize molecules.
D) when tuned to energy levels of water releases the energy as heat.

Question 32

Which is not used when trying to ensure that autoclaving has achieved sterility?

A) internal devices to maintain proper temperature and pressure
B) tapes impregnated with the word "sterile" when proper temperature has been reached
C) pasteurization by heating to 62.9 °C for 30 minutes
D) autoclaving heat-resistant endospores such as Bacillus stearothermophilus

Question 33

Ultraviolet radiation

A) is the same as X rays
B) is the same as gamma rays
C) penetrates glass, cloth, paper and most other materials
D) kills microorganisms by damaging DNA and proteins

Question 34

All of the following are examples of general types of radiation except

A) ultraviolet light
B) ionization
C) microwaves
D) ultrasonic waves

Question 35

All of the following pertain to either sonic or ultrasonic waves and their properties except

A) are sound waves in the audible range
B) cause cavitation-partial vacuum in a liquid
C) are a practical means of sterilization
D) useful means of fragmenting cells to study membranes, ribosomes or enzymes

Question 36

Which of the following antimicrobial agents is not considered a halogen?

A) hypochlorous acid
B) copper sulfate
C) bromine
D) betadine

Question 37

Formaldehyde,as an antimicrobial agent,is used for the following purposes

A) food preservation
B) disinfect skin and inanimate objects
C) treat protozoan and fungal infections
D) inactivate viruses without destroying antigenic properties

Question 38

Which of the following statements about detergents is true?

A) detergents act as chemical mutagens of DNA or RNA
B) germicidal soaps are just as effective disinfectants as surgical scrubs
C) cationic detergents are effective in killing endospores
D) anionic detergents used for laundering clothes are less effective than cationic detergents

Question 39

Dyes that are used as antimicrobial agents function by

A) disrupting disulfide bonds.
B) interfering with replication or blocking cell wall synthesis.
C) denaturing proteins by mixing with water.
D) oxidizing cellular components.

Question 40

Dry heat does most of its damage against microorganisms by

A) disrupting membrane lipids.
B) disrupting hydrogen bonds.
C) oxidizing molecules.
D) denaturing proteins.

Question 41

Compare the meanings of the following paired terms: a)disinfectant and antiseptic; b)bactericidal agent and bacteriostatic agent; and c)sterilization and disinfection. When is it worthwhile to pay extra for a sanitized item?

Question 42

High concentrations of solutes such as sugar or salt results in plasmolysis of cells due to the onset of which phenomenon.

A) cavitation
B) ultrahigh temperature
C) low lyophilization
D) high osmotic pressure

Question 43

What makes a disinfectant desirable? Describe one method for determining the effectiveness of a chemical agent.

Question 44

Which is not a practical means of killing microorganisms?

A) pasteurization
B) freeze-drying
C) ultrasonic waves
D) ultraviolet light

Question 45

Moist heat kills microorganisms by denaturing their

A) lipids
B) proteins
C) carbohydrates
D) nucleic acids

Question 46

What is the cheapest and easiest means to prevent the spread of disease?

A) vigorous hand washing
B) pasteurizing milk
C) filtering air in tuberculosis rooms
D) exposing operating rooms to ultraviolet light

Question 47

Which is a good method to sterilize bandages and glassware?

A) autoclaving
B) lyophilization
C) microwave radiation
D) two of the above

Question 48

Filtering water through paper

A) reduces contamination
B) sterilizes the water
C) prevents the spoilage of foods
D) two of the above

Question 49

Membrane filters are used for sterilization because

A) filters with smallest pore size do not clog easily.
B) many materials are destroyed by heat sterilization
C) they are used to sterilize only very small amounts of liquid
D) they are impractical for the filtration of beer, sera, media, vitamins and drugs.

Question 50

Which sterilization technique would you use on pharmaceutical products?

A) autoclaving
B) ionizing radiation
C) ultrasonic waves
D) detergent

Question 51

When food is salted,water diffuses ________microorganisms,causing them to ____ and die.

A) into; shrink
B) into; explode
C) out of; shrink
D) out of; explode

Question 52

What sterilization technique should be used on beer and milk?

A) pasteurization
B) ultraviolet light
C) filtration
D) visible light

Question 53

Which is a good method to sterilize food?

A) freezing
B) lyophilization
C) drying
D) two of the above

Question 54

Most milk,cheese and juices in the United States are pasteurized. Describe the process of pasteurization and the microorganisms at which it is directed. Do you consider pasteurized milk a sterile product? Why?

Question 55

What sterilization technique should be used for sterilizing instruments

A) filtration
B) direct flame
C) pasteurization
D) autoclaving

Question 56

Dry heat changes the structure of _______ through the process of _____

A) lipids; dehydration
B) lipids; oxidation
C) proteins; oxidation
D) proteins; dehydration

Question 57

Which of the following statements about heat is true?

A) thermal death point is the time required to kill all bacteria in a culture
B) moist heat penetrates substances more slowly than dry heat
C) dry heat leads to the oxidation of molecules
D) moist heat disrupts covalent bonds