Deck 8: Control of Microorganisms in the Environment

Question 1

An agent that prevents the growth of bacteria without causing irreversible damage to the bacteria is referred to as __________.

Answer 1

bacteriostatic

Question 2

When antiseptics and disinfectants are compared,antiseptics are generally

A)less toxic.
B)more toxic.
C)equally as toxic.
D)unpredictable in toxicity.

Answer 2

A

Question 3

Sterilization involves __________ all viable microorganisms.

A)killing
B)removing
C)killing OR removing
D)metabolically inactivating

Answer 3

C

Question 4

A(n)__________ is a chemical that can be used to sterilize materials.

A)oxidant
B)disinfectant
C)antiseptic
D)sterilant

Question 5

The rate of killing by an antimicrobial agent may slow when the microbial population has been greatly reduced because the remaining population may have a high proportion of resistant organisms.

Question 6

Which of the following influence(s)the efficiency of an antimicrobial agent?

A)Concentration of the agent.
B)Duration of exposure.
C)Temperature.
D)All of the choices.

Question 7

The prevention of infection caused by microorganisms is called

A)disinfection.
B)antisepsis.
C)sterilization.
D)sanitization.

Question 8

An agent that kills bacteria is referred to as __________.

Question 9

The substantial reduction of the total population of microorganisms on inanimate objects and the destruction of potential pathogens is called

A)disinfection.
B)antisepsis.
C)sterilization.
D)sanitization.

Question 10

Larger populations generally are killed as rapidly as smaller populations.

Question 11

Microorganisms show differential sensitivity to antimicrobial agents.

Question 12

Which will require a longer time to kill?

A)A larger population of microorganisms.
B)A smaller population of microorganisms.
C)Killing will be equally as rapid in a large or a small microbial population.
D)There is no way to predict which will require a longer kill time.

Question 13

Which of the following inhibits bacterial growth but does not kill bacteria

A)Lysozyme.
B)Bactericidal agent.
C)Bacteriostatic agent.
D)Antiseptic agent.

Question 14

All germicides are capable of killing all pathogenic organisms and endospores.

Question 15

Which of the following represents the best definition for microbial death?

A)The organism will not grow on minimal medium.
B)The organism will not grow on a medium that normally supports its growth.
C)The organism no longer retains its original shape and structures.
D)None of these adequately describe microbial death.

Question 16

The reduction of the microbial population to levels that are considered safe by public health standards is called

A)disinfection.
B)antisepsis.
C)sterilization.
D)sanitization.

Question 17

An agent that specifically kills fungi but not other kinds of microorganisms is also known as a

A)fungistatic agent.
B)mycostatic agent.
C)fungicidal agent.
D)germicidal agent.

Question 18

Which of the following environmental factors generally do(es)not have an impact on the efficiency of an antimicrobial agent?

A)PH.
B)Presence or absence of a biofilm.
C)Concentration of organic matter.
D)Refractive index.

Question 19

The time required to kill 90% of the microorganisms or spores in a sample at a specified temperature is the

A)thermal death time (TDT).
B)thermal death point (TDP).
C)decimal reduction time (D value).
D)z value.

Question 20

The destruction or removal of all viable organisms is called

A)disinfection.
B)antisepsis.
C)sterilization.
D)sanitization.

Question 21

Which of the following is not a method of heat sterilization?

A)Autoclaving.
B)Incineration.
C)Pasteurization.
D)Heating in a dry air oven.

Question 22

Which of the following lacks sufficient penetrating power for bulk sterilization?

A)Ultraviolet (UV)radiation at 260 nm.
B)X rays.
C)Gamma radiation.
D)Alpha and beta particles.

Question 23

If one left a "Pasteurized" flask of broth for a long time at room temperature,it would stay sterile forever,at least in principle.

Question 24

Which of the following is MOST effective against resistant endospores?

A)autoclaving
B)boiling
C)pasteurization
D)All of these are equally effective against resistant endospores.

Question 25

Because filtration removes rather than destroys microorganisms,it does not truly sterilize the materials passing through the filter.

Question 26

Gamma radiation

A)is a type of nonionizing radiation.
B)has poor penetrating power.
C)is used to sterilize some food products.
D)has a longer wavelength than UV radiation.

Question 27

The type of filter used in a laminar flow biological safety cabinet is called a(n)__________ filter.

Question 28

Ultraviolet radiation is an effective means of sterilizing surfaces.

Question 29

Which of the following is true about membrane filters?

A)It can be used only to remove organisms from liquids.
B)It does not truly sterilize because it removes rather than kills microorganisms.
C)It can be used only to remove organisms from liquids and it does not truly sterilize because it removes rather than kills microorganisms.
D)It can't be depended on to remove all viruses from liquids.

Question 30

The first product to be commercially treated by pasteurization was

A)milk
B)wine
C)beer
D)cheese

Question 31

Dry heat methods usually require lower temperatures and shorter exposure times than moist heat methods to achieve the same degree of killing because of the drying effects of this form of heat.

Question 32

Pasteurization is used to

A)Kill any pathogens present.
B)Retard spoilage.
C)Sterilize beverages.
D)Kill any pathogens present and retard spoilage.

Question 33

Heavy metals may inactivate proteins by reacting with their sulfhydryl groups.

Question 34

Which kind of sterilization procedure takes advantage of the size of microorganisms?

A)autoclaving
B)open flame
C)use of chemicals
D)filtration

Question 35

When comparing dry heat and moist heat sterilization,dry heat is

A)faster.
B)slower.
C)equally as fast.
D)sometimes faster but sometimes slower.

Question 36

Moist heat sterilization at 100 $\degree$ C kills all of the following except

A)bacterial endospores.
B)fungal spores.
C)viruses.
D)bacterial endospores and fungal spores.

Question 37

Joseph Lister

A)pioneered the use of gamma rays for sterilizing food.
B)demonstrated that microorganisms are carried on dust particles in the air.
C)revolutionized surgery by introducing phenol as a disinfectant.
D)designed and built the first autoclave.

Question 38

Which of these is an agent that is used to sterilize the plastic tubing of heart-lung machines?

A)phenol
B)mercaptoethanol
C)ethylene oxide
D)70% ethanol

Question 39

Which of the following is a function of pasteurization?

A)killing pathogenic microorganisms
B)reducing the total microbial population
C)increasing the shelf life of the product
D)all of the choices

Question 40

Moist heat sterilizes by

A)causing the formation of thymine dimers.
B)denaturing proteins.
C)causing production of singlet oxygen.
D)all of the choices

Question 41

The higher the phenol coefficient value,the _______ effective the disinfectant under the test conditions.

Question 42

Amphipathic organic molecules that serve as disinfectants by disrupting membranes and denaturing proteins are called

A)sterilants.
B)oxidants.
C)detergents.
D)soaps.

Question 43

Antiseptics are generally regulated by the

A)Food and Drug Administration.
B)Environmental Protection Agency.
C)The National Institutes of Health.
D)Centers for Disease Control and Prevention.

Question 44

Although heavy metals are no longer widely used as germicides,__________ is an effective algicide in lakes and swimming pools.

A)lead acetate
B)copper sulfate
C)silver nitrate
D)mercuric chloride

Question 45

Bacteriophage therapy was developed after antibiotics were first discovered and used for treating bacterial infections.

Question 46

The disinfectant of choice for municipal water supplies is __________.

A)fluorine
B)chlorine
C)either fluorine or chlorine
D)ultraviolet light

Question 47

The disinfectant action of phenol and phenolic derivatives mainly is due to

A)its inherent detergent action.
B)membrane damage and protein denaturation.
C)oxidation of disulfide bonds in proteins.
D)extraction of lipids from membranes.
E)damage to nucleic acids and proteins caused by free radicals.

Question 48

The disinfecting properties of Lysol,a common household disinfectant,depend upon the presence of __________.

Question 49

The disinfectant screening method that is known as the ________ _________ test,which is used to measure the potency of a disinfectant.

Question 50

Iodine can be complexed with an organic carrier to form water-soluble,stable complexes called __________,which release iodine slowly and eliminate skin burns and irritation associated with iodine use.

A)iodides
B)tinctures
C)iodophors
D)iodochromes

Question 51

Heavy metals are effective antimicrobial agents but are not widely used because of their high toxicity to humans.

Question 52

The two most important alcohol germicides are __________ and __________.

A)ethanol; methanol
B)ethanol; isopropanol
C)methanol; butanol
D)methanol; isopropanol

Question 53

Alcohols are widely used as antiseptics and disinfectants because they are effective against endospores as well as vegetative cells.

Question 54

Which of the following is (are)a sterilizing gas(es)that can be used on heat-sensitive materials?

A)ethylene oxide
B)glutaraldehyde
C)chlorine gas
D)isopropanol

Question 55

Disinfectants are generally regulated by the

A)Food and Drug Administration.
B)Environmental Protection Agency.
C)The National Institutes of Health.
D)Centers for Disease Control and Prevention.

Question 56

Betapropiolactone is not as useful as ethylene oxide as a sterilizing agent because it does not penetrate materials as readily as ethylene oxide.