Ch.8 Control Of Microorganisms In The + Verified Test Bank

Prescott's Microbiology, 11e (Willey)

Chapter 8 Control of Microorganisms in the Environment

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

A) Lysozyme

B) Bactericidal agent

C) Bacteriostatic agent

D) Antiseptic agent

2) When antiseptics and disinfectants are compared, antiseptics are generally ________.

A) less toxic

B) more toxic

C) equally as toxic

D) unpredictable in toxicity

3) 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

4) Sterilization involves ________ all viable microorganisms.

A) killing

B) removing

C) killing OR removing

D) metabolically inactivating

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

A) oxidant

B) disinfectant

C) antiseptic

D) sterilant

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

7) An agent that kills bacteria is referred to as ________.

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

9) The destruction or removal of all viable organisms is called ________.

A) disinfection

B) antisepsis

C) sterilization

D) sanitization

10) 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

11) The prevention of infection caused by microorganisms is called ________.

A) disinfection

B) antisepsis

C) sterilization

D) sanitization

12) 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

13) 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 choices adequately describe microbial death.

14) 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

15) 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.

16) 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 are correct.

17) Larger populations generally are killed as rapidly as smaller populations.

18) 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.

19) Microorganisms show differential sensitivity to antimicrobial agents.

20) 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

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

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.

23) 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

24) Moist heat sterilization at 100°C kills all of the following EXCEPT ________.

A) bacterial endospores

B) fungal spores

C) viruses

D) protists

25) 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

26) 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 are correct.

27) 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.

28) 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

29) The first product to be commercially treated by pasteurization was ________.

A) milk

B) wine

C) beer

D) cheese

30) Pasteurization is used to ________.

A) kill any pathogens present

B) retard spoilage

C) sterilize beverages

D) kill any pathogens present and retard spoilage

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

A) Autoclaving

B) Open flame

C) Use of chemicals

D) Filtration

32) Ultraviolet radiation is an effective means of sterilizing surfaces.

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

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

35) 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.

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

37) 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 are correct.

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

39) 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

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

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

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

43) 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

44) The disinfecting properties of Lysol, a common household disinfectant, depend upon the presence of ________.

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

46) Amphipathic organic molecules that serve as disinfectants by disrupting membranes and denaturing proteins are called ________.

A) sterilants

B) oxidants

C) detergents

D) soaps

47) The disinfectant of choice for municipal water supplies is ________.

A) fluorine

B) chlorine

C) either fluorine or chlorine

D) ultraviolet light

48) 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

49) 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

50) The two most important alcohol germicides are ________ and ________.

A) ethanol; methanol

B) ethanol; isopropanol

C) methanol; butanol

D) methanol; isopropanol

51) 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

52) 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

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

54) The higher the phenol coefficient value, the ________ effective the disinfectant under the test conditions.

A) more

B) less

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

56) Which of the following would be most appropriate for removal of bacteria and some viruses from a liquid?

A) HEPA filter

B) N95 filter

C) Membrane filter (< 0.1μm)

D) Depth filter (diatomaceous earth)

57) A biological safety cabinet filters out more microorganisms than an N95 mask.

58) Several new materials have been developed for use in the microbiology lab. These materials must be sterilized before use, but cannot withstand a temperature over 60oC and can't be exposed to water. Which method of sterilization would be applicable?

A) Steam autoclave

B) Oven-dry heat

C) UV radiation

D) Ionizing radiation

59) Portable UV room sterilizing units are being used to reduce endospores of Clostridioides difficile in hospital rooms after patients have vacated. Which of the statements best describes this application?

A) UV radiation will not destroy C. difficile endospores.

B) UV radiation will destroy C. difficile endospores assuming it is applied for a long enough period and directly contacts all surfaces.

C) UV radiation will destroy C. difficile endospores and penetrates well to all locations within the room.

D) UV radiation will destroy C. difficile endospores and has residual sporicidal effects that will persist after the unit has been removed from the patient's room.

60) Which of the following would be most effective and practical for routine home disinfection of a toothbrush between uses?

A) 70% Isopropyl alcohol

B) Glutaraldehyde

C) Bleach

D) Hydrogen peroxide

61) Which of the following would be most effective and practical for routine home disinfection of a kitchen sponge between uses?

A) 70% Isopropyl alcohol

B) Iodophor

C) Chlorine bleach

D) Hydrogen peroxide

62) Bacterial pathogens may be controlled by ________, which are viruses that specifically infect and lyse the bacterial host.

63) Which of the following is a Gram-negative bacterium that acts as a predator on other Gram-negative bacteria, and might be used to control populations of Gram-negative human pathogens in locations such as poultry farms?

A) E. coli

B) Salmonella enteritidis

C) Bdellovibrio

D) Vibrio choerae

64) Which of the following is/are advantages of using bacteriophage to treat human bacterial infections?

A) Bacteriophage can kill the bacteria.

B) Bacteriophage will not cause disease or harm humans.

C) Bacteriophage are very specific for the target bacteria and won't affect normal microbiota.

D) All of the choices are correct.

65) The use of bacteriophage to treat human infections is referred to as ________  ________.

66) Fecal transplants have been successfully used to treat Clostridioides difficile colitis by reintroducing healthy fecal microbiota that outcompete the C. difficile.

67) Which of the following is not true regarding the decimal reduction time?

A) It is a measure of the effective concentration of disinfectant that kills within a specific time period

B) It is the time taken to reduce the number of pathogens in a sample by one log cycle

C) The Z value is the temperature equivalent of the D value

D) Once the number of organisms has been reduced to 10%, the killing may slow due to resistant strains that remain in the population

68) A peptidoglycan-hydrolyzing protein isolated from bacteriophage P68 has been used in synergy with the antimicrobial agent gentamicin, enhancing the antimicrobial effects of the drug toward Staphylococcus aureus.  This is an example of microbial control by ________.

A) enzybiotics

B) sterilization

C) predation

D) antisepsis

E) heavy metals