Deck 8: Control of Microorganisms in the Environment

Question 1

Larger populations generally are killed as rapidly as smaller populations.

Answer 1

False

Question 2

The destruction or removal of all viable organisms is called

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

Answer 2

C

Question 3

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.

Answer 3

B

Question 4

Microorganisms show differential sensitivity to antimicrobial agents.

Question 5

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 6

When antiseptics and disinfectants are compared, antiseptics are generally

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

Question 7

The prevention of infection caused by microorganisms is called

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

Question 8

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 9

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

A) lysozyme
B) bactericidal agent
C) bacteriostatic agent
D) antiseptic agent

Question 10

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

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

Question 11

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 12

An agent that kills bacteria is referred to as __________.

Question 13

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 14

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

Question 15

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

Question 16

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 17

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 18

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 19

Sterilization involves __________ all viable microorganisms.

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

Question 20

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 21

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 22

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 23

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 24

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

Question 25

Ultraviolet radiation is an effective means of sterilizing surfaces.

Question 26

Pasteurization is used to

A) kill any pathogens present
B) retard spoilage
C) sterilize beverages
D) kill any pathogens present and retard spoilage

Question 27

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 28

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

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

Question 29

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 30

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 31

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

Question 32

The first product to be commercially treated by pasteurization was

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

Question 33

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 34

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 35

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

Question 36

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 37

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 38

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 39

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 40

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 41

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

Question 42

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 43

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 44

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 45

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

Question 48

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 49

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

Question 50

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

Question 51

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

Question 52

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

Question 53

The two most important alcohol germicides are __________ and __________.

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

Question 54

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

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

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

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