Deck 13: Sterilization and Disinfection

Question 1

Surfactants include all of the following except:

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

Answer 1

D

Question 2

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 vegetative microorganisms to pose no threat of disease.

Answer 2

D

Question 3

An agent that inhibits the growth of bacteria is called a/an:

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

Answer 3

C

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 are examples of heavy metals used as antimicrobial agents EXCEPT:

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

Question 6

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 7

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 8

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 9

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 10

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

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

Question 11

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 12

All of the following qualities apply to the selection of an ideal antiseptic EXCEPT:

A)fast acting
B)effective against all infective agents without harming host tissue
C)no offensive odor
D)expensive and difficult to obtain and use

Question 13

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 14

Agents that adversely affect cell wall formation include:

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

Question 15

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

A)antiseptic
B)disinfectant
C)sanitizer
D)all of these

Question 16

Which of the following do NOT affect viruses

A)Alkylating agents
B)Detergents
C)Alcohols
D)Heavy Metals

Question 17

Agents that denature proteins include all of the following except:

A)acids
B)alkalis
C)detergents
D)cold treatment

Question 18

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 19

All of the following pertain to the effectiveness of a chemical antimicrobial agent EXCEPT:

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

Question 20

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 21

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 22

Alcohols:

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

Question 23

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 in a/an:

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

Question 24

Ionizing radiation:

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

Question 25

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 26

Which of the following is not an example of an alkylating agent that disrupts proteins and nucleic acids

A)Glutaraldahyde
B)β-propiolactone
C)Ethylene oxide
D)Methylene oxide

Question 27

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 28

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 29

Lyophilization is:

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

Question 30

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

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

Question 31

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 32

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 33

Which of the following antimicrobial agents is NOT considered a halogen

A)Hypochlorous acid
B)Copper sulfate
C)Bromine
D)Betadine

Question 34

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 35

Which of the following statements about detergents are 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 36

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 37

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 38

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 these

Question 39

Formaldehyde,as an antimicrobial agent,is used for:

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

Question 40

All of the following pertain to sonic or ultrasonic waves and their properties,EXCEPT:

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

Question 41

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

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

Question 42

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 43

Foods should not be refrozen because

A)they will taste different
B)cellular damage changes texture,allowing nutrient loss and increased spoilage potential
C)it prevents the spoilage of foods
D)all of these

Question 44

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 45

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.

Question 46

Which is not a practical means of killing microorganisms or inhibiting the activity of microorganisms

A)Pasteurization
B)Freeze-drying
C)Ultrasonic waves
D)Ultraviolet light

Question 47

Moist heat kills microorganisms by denaturing their _____.

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

Question 48

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 49

Which sterilization technique would you use on pharmaceutical products

A)Autoclaving
B)Ionizing radiation
C)Ultrasonic waves
D)Detergent

Question 50

What sterilization technique should be used for sterilizing instruments

A)Filtration
B)Disinfection
C)Pasteurization
D)Autoclaving