Microbiology Bio 150- Exam 2 Chapter 11

23. The minimum sterilizing conditions in a steam autoclave are A. 121°C at 15 psi for 15 minutes. B. 63°C for 30 minutes. C. 100°C for 30 minutes. D. 160°C for 2 hours. E. 71.6°C for 15 seconds.

A. 121°C at 15 psi for 15 minutes.

19. Which of the following does not affect microbial nucleic acids? A. Moist heat B. Ultraviolet light C. X rays D. Ethylene dioxide E. Formaldehyde

A. Moist heat

Which of the following methods of microbial control is mismatched? A. Pickling eggs - osmotic pressure B. Exposure of surgical equipment to ultraviolet light - radiation C. Heating a liquid to 71.6oC for 15 seconds - pasteurization D. Autoclaving nutrient agar before pouring into Petri plates - sterilization

A. Pickling eggs - osmotic pressure

56. Which of the following is not a heavy metal? A. Tincture of iodine B. Merthiolate C. Silver nitrate solution D. Zinc E. Mercurochrome

A. Tincture of iodine

39. Which control method would not be a suitable choice for killing Mycobacterium in a capped culture tube? A. Ultraviolet (germicidal) light B. Gamma rays C. 121°C at 15 psi for 15 minutes D. 160°C for 2 hours E. All of the choices are correct.

A. Ultraviolet (germicidal) light

41. HEPA filters are used to remove microbes from A. air. B. liquids. C. human tissues. D. medical instruments. E. All of the choices are correct.

A. air.

11. The alcohol wipe used on a patient's skin before an injection is an example of ______. A. antisepsis B. disinfection C. sterilization D. decontamination E. sanitization

A. antisepsis

9. The method of removing vegetative life forms from living surfaces is termed ______. A. antisepsis B. disinfection C. sterilization D. decontamination

A. antisepsis

46. Iodophors include ______. A. betadine B. chlorhexidine C. alcohols D. chloramines E. tincture of iodine

A. betadine

3. The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is ______. A. disinfection B. sterilization C. antisepsis D. sanitization E. degermation

A. disinfection

49. The chemical agent/s that produce/s highly reactive hydroxyl-free radicals and also decomposes to O2 gas is ______. A. hydrogen peroxide B. chlorhexidine C. iodophors D. cationic detergents E. Cidex

A. hydrogen peroxide

22. Dry heat A. is less efficient than moist heat. B. cannot sterilize. C. includes tyndallization. D. is used in devices called autoclaves. E. will sterilize at 121°C for 15 minutes.

A. is less efficient than moist heat

25. The lowest temperature needed to kill or inactivate all microbes in 10 minutes is the A. thermal death point (TDP). B. thermal death time (TDT). C. sporicidal time. D. death phase point.

A. thermal death point (TDP).

59. Which of the following is not used as an antiseptic? A. Iodophor B. Aqueous glutaraldehyde C. 3% hydrogen peroxide D. Chlorhexidine E. Merthiolate

B. Aqueous glutaraldehyde

47. _____ is a halogen used in gaseous and liquid form for large scale disinfection of drinking water and sewage. A. Iodine B. Chlorine C. Bromine D. Fluorine E. Betadine

B. Chlorine

43. _____ is a control method that removes microorganisms rather than inhibiting or killing them. A. Disinfection B. Filtration C. Boiling D. Radiation E. Sterilization

B. Filtration

40. Which of the following forms of radiation are in order from the most penetrating to the least penetrating? A. Gamma, cathode, X rays B. Gamma, X rays, cathode C. Cathode, gamma, X ray D. X ray, gamma, cathode E. Cathode, X ray, gamma

B. Gamma, X rays, cathode

90. You have inherited some old glass baby milk bottles from your grandmother, and you would like to use them instead of plastic bottles. The bottles are placed into a large metal container and placed in the oven at 325oF for about 2 hours. What factor would you change if you wanted the sterilization to occur much quicker? A. Place the bottles outside in the sunlight and then place in the oven B. Use a pressure cooker to sterilize the bottles with steam C. Pour an antimicrobial chemical into the bottles before placing into the oven D. Increase the temperature of the oven by 5 degrees

B. Use a pressure cooker to sterilize the bottles with steam

27. Placing organisms at 4oC is ______. A. bactericidal B. bacteriostatic C. decontamination D. sterilization E. germicidal

B. bacteriostatic

68. In lab, inoculating loops are sterilized using ______. A. chemicals B. incineration C. filtration D. moist heat E. gas sterilization

B. incineration

14. Microbial death occurs when there is A. no movement. B. no reproduction. C. a change in appearance. D. a decrease in size. E. All of the choices occur.

B. no reproduction.

28. Pasteurization A. kills all vegetative forms. B. reduces the number of vegetative forms. C. reduces the number of endospores. D. increases food nutrient value. E. is used to sterilize food products.

B. reduces the number of vegetative forms.

2. The process that destroys or removes all microorganisms and microbial forms, including bacterial endospores, on inanimate objects is ______. A. disinfection B. sterilization C. antisepsis D. sanitization E. degermation

B. sterilization

24. The shortest time required to kill or inactivate all the microbes in a sample at a specified temperature is called the A. thermal death point (TDP). B. thermal death time (TDT). C. sporicidal time. D. death phase point.

B. thermal death time (TDT).

96. When considering time and temperature as factors in microbicidal activity, A. they are directly proportional to each other. B. they are inversely proportional to each other. C. they must be of equal value e.g. 30 minutes at 30oC. D. time is not a factor, only temperature.

B. they are inversely proportional to each other.

7. The easiest microbial forms to kill or inhibit are ______. A. naked viruses B. vegetative bacteria and fungi C. endospores D. protozoan cysts E. mycobacteria and staphylococci

B. vegetative bacteria and fungi

12. Which is correct regarding the rate of microbial death? A. Cells die at increasingly greater rates. B. Only older cells die in a culture. C. Cells in a culture die at a constant rate. D. Upon contact with the control agent, all cells die at one time. E. Cells become metabolically inactive but are never killed.

C. Cells in a culture die at a constant rate.

98. Which of the following is true regarding the use of osmotic pressure as an antimicrobial agent? A. Salts and sugars external to a microbe create a hypotonic environment, which causes lysis of the cell. B. Salt is an effective solute to create an osmotic pressure gradient outside of a cell; however, the use of sugar, such as in jams and jellies, works via a different mechanism. C. Exposing a microbe to a hypertonic environment draws water out of the cell, causing plasmolysis. D. Exposing organisms to the air on a benchtop so they completely dry out is an example of using osmotic pressure as a means of microbial control.

C. Exposing a microbe to a hypertonic environment draws water out of the cell, causing plasmolysis.

91. Your aim is to sterilize prosthetic devices like heart valves and artificial joint structures before being used in the patient. Considering where they will be placed and the probable composition of the devices, what would be the best chemical to use? A. Crystal violet dye B. Iodine C. Quaternary ammonium compounds D. Bleach

C. Quaternary ammonium compounds

4. The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is ______. A. disinfection B. sterilization C. antisepsis D. sanitization

C. antisepsis

55. All of the following act as surfactants except ______. A. detergents B. quaternary ammonia C. iodine D. soaps E. alcohols

C. iodine

26. Disinfection of beverages such as apple juice, milk, and wine is optimally achieved by ______. A. filtration B. chlorination C. pasteurization D. boiling water E. moist heat autoclave

C. pasteurization

10. The removal of all life forms from inanimate objects is termed ______. A. antisepsis B. disinfection C. sterilization D. decontamination E. degerming

C. sterilization

69. Antimicrobial agents can target the cell wall by A. blocking its synthesis. B. digesting it. C. denaturing proteins. D. All of the choices are correct.

D. All of the choices are correct.

1. Which of the following microbial forms has the highest resistance to physical and chemical controls? A. Naked viruses B. Protozoan cysts C. Fungal spores D. Bacterial endospores E. Yeast

D. Bacterial endospores

29. _____ heat is more rapidly effective and efficient compared to _____ heat. A. High; dry B. High; moist C. Dry; moist D. Moist; dry E. Moist; high

D. Moist; dry

92. Which antimicrobial method does not sterilize? A. Ionizing radiation B. Ethylene oxide gas C. Autoclave D. Pasteurization

D. Pasteurization

6. Which of the following types of control agents would be used to achieve sterility? A. Virucide B. Bactericide C. Germicide D. Sporicide E. Fungicide

D. Sporicide

5. Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is ______. A. disinfection B. sterilization C. sanitization D. degermation

D. degermation

17. Some microbial control agents are able to _____ cell proteins by breaking bonds that maintain the native state, the three-dimensional configuration of the proteins. A. mutate B. bind C. dissolve D. denature

D. denature

16. Surfactants work by A. coating the organism preventing interaction with its environment. B. blocking transport into the organism. C. blocking transport out from the organism. D. disrupting membrane integrity.

D. disrupting membrane integrity.

20. Physical agents for controlling microbial growth include all of the following except ______. A. ultraviolet radiation B. boiling water C. pasteurization D. hydrogen peroxide

D. hydrogen peroxide

21. Sterilization is achieved by A. flash pasteurization. B. hot water. C. boiling water. D. steam autoclave. E. All of the choices are correct.

D. steam autoclave.

95. The difference between thermal death time and thermal death point in microbicidal activity is that A. thermal death time is the greatest amount of time required to kill an organism at a specific temperature, . whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes. B. thermal death time is the shortest amount of time required to kill an organism at a specific temperature, whereas thermal death temperature is the lowest temperature required to kill an organism in 30 minutes. C. thermal death time is the shortest amount of time required to kill an organism at a 100oC, whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes. D. thermal death time is the shortest amount of time required to kill an organism at a specific temperature, . whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes.

D. thermal death time is the shortest amount of time required to kill an organism at a specific temperature, . whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes.

38. Which of the following items are typically irradiated in order to kill microbes? A. Cured meats B. Human tissues such as heart valves and skin C. Operating room air D. Surgical gloves E. All of the choices are correct.

E. All of the choices are correct

54. Hydrogen peroxide is A. sporicidal. B. fungicidal. C. bactericidal. D. virucidal. E. All of the choices are correct.

E. All of the choices are correct.

61. Endospores can be inactivated by A. dry heat at 170°C for 2 hours. B. incineration. C. glutaraldehyde for 3 or more hours. D. ethylene oxide for 3 or more hours. E. All of the choices are correct.

E. All of the choices are correct.

44. Which of the following is not a factor that affects germicidal activity? A. Material being treated B. Length of exposure C. Strength of the germicide D. Microorganism being treated E. All of the choices are factors.

E. All of the choices are factors.

13. Which of the following factors will influence the action of microbial agents? A. The number of microorganisms B. The type of microorganisms present C. Temperature and pH D. Mode and dosage of the agent E. All of the choices will influence the action.

E. All of the choices will influence the action.

48. Which of the following is not true of chloramines? A. They contain chlorine. B. They are used to treat wounds and skin surfaces. C. They are safer than free chlorine. D. They can sanitize and disinfect. E. They form trihalomethanes with organic compounds.

E. They form trihalomethanes with organic compounds.

18. Agents that can denature microbial proteins include all of the following except ______. A. moist heat B. alcohol C. acids D. metallic ions E. X rays

E. X rays

42. The use of filtration for sterilization A. leaves behind endospores. B. removes toxins. C. uses heat and filtration. D. relies on gravity. E. can remove viruses.

E. can remove viruses.

15. Each of the following is a target of antimicrobial agents except ______. A. cell walls B. cell membranes C. ribosomes D. cellular proteins E. cytoplasm

E. cytoplasm

8. The method of removing vegetative microbial life forms and debris to reduce contamination to safe levels is termed ______. A. antisepsis B. disinfection C. sterilization D. decontamination E. sanitization

E. sanitization

45. All of the following pertain to hypochlorites except A. they cause denaturation of enzymes. B. they release hypochlorous acid in solution. C. they are found in common household bleach. D. they are used to disinfect dairy, restaurant, and medical equipment. E. they are found in iodophors.

E. they are found in iodophors.

101. Continued widespread use of the phenolic compound triclosan is advantageous in that it is important to remove as many organisms as possible from our hands and there is little risk of resistant organisms evolving.

FALSE

102. Surgeons preparing for an invasive surgical procedure will scrub their hands thoroughly, and then they use a strong alcohol-based hand sanitizer which renders their hands sterile.

FALSE

71. All microbicidal agents are sterilants.

FALSE

72. Bacteriostatic agents kill bacterial cells.

FALSE

76. A microorganism that is not motile and has stopped metabolizing is considered dead.

FALSE

76. Most microbial contaminants of food are killed or inactivated at freezing temperatures.

FALSE

78. Pasteurization is used to sterilize milk.

FALSE

81. Chlorine compounds remain stable and effective in the presence of excess organic matter.

FALSE

83. Isopropyl alcohol wiped across a skin site can sterilize it.

FALSE

86. Soaps and detergents are very effective as sterilants.

FALSE

73. Prions require more extensive methods of sterilization than are needed for bacterial endospores.

TRUE

74. The presence of organic matter such as saliva and pus can interfere with the actions of disinfectants.

TRUE

75. When a control agent targets the metabolic processes of microbial cells, active younger cells typically die more rapidly than older cells.

TRUE

79. Pasteurization does not inactivate endospores or thermoduric microbes.

TRUE

80. Ionizing radiation is more effective than nonionizing radiation in killing or inactivating microbes.

TRUE

82. Alcohols are more effective at inactivating enveloped viruses than naked viruses.

TRUE

85. Ozone is a very effective disinfectant.

TRUE

87. Organisms in the genus Pseudomonas are resistant to quats.

TRUE

88. Chlorine and ethylene oxide are sterilizing gases.

TRUE

Hydrogen peroxide is used in the process of sterilizing instruments such as endoscopes.

TRUE