Ch 11 Microbiology

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1. Microbiological contaminants are best described as:
A) unwanted microbes present on or in a substance
B) any and all microbes present on or in a substance
C) pathogenic microbes present on or in a substance
D) vegetative microbes present on or in a substance
E) none of the choices are correct

unwanted microbes present on or in a substance

2. Physical agents for controlling microbial growth include all the following except:
A) ultraviolet radiation
B) boiling water
C) HEPA filters
D) pasteurization
E) hydrogen peroxide

hydrogen peroxide

3. Which of the following microbial forms have the highest resistance to physical and chemical controls?
A) naked viruses
B) protozoan cysts
C) fungal spores
D) hydrogen peroxide
E) yeast

hydrogen peroxide

4. The process that destroys or removes all microorganisms and microbial forms including bacterial endospores is:
A) disinfection
B) sterilization
C) antisepsis
D) sanitization
E) degermation

sterilization

5. The process of using a cleansing technique to mechanically remove and reduce microorganisms and debris to safe levels is:
A) disinfection
B) sterilization
C) antisepsis
D) sanitization
E) degermation

sanitization

6. The use of a physical or chemical process to destroy vegetative pathogens is:
A) disinfection
B) sterilization
C) antisepsis
D) sanitization
E) degermation

disinfection

7. 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
E) degermation

antisepsis

8. Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is:
A) disinfection
B) sterilization
C) antisepsis
D) sanitization
E) degermation

degermation

9. Which of the following types of control agents would be used to achieve sterility?
A) virucide
B) bactericide
C) germicide
D) sporicide
E) fungicide

sporicide

10. 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) involves the permanent termination of an organisms vital processes
D) upon contact with the control agent, all cells die at one time
E) cells become metabolically inactive but are never killed

involves the permanent termination of an organisms vital processes

11. Sterilization is achieved by:
A) flash pasteurization
B) hot water
C) boiling water
D) steam autoclave
E) all of the choices are correct

steam autoclave

12. 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

dry heat at 170 C for 2 hours

13. Endospores can be killed by:
A) dry heat at 170 C for 2 hours
B) incineration
C) glutaldehyde for 3 or more hours
D) ethylene oxide for 3 or more hours
E) all of the choices are correct

all of the choices are correct

14. 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) 160 C for 2 hours
D) 71.6 C for 15 seconds
E) 100 C for 30 minutes

121 C at 15 psi for 15 minutes

15. The shortest time required to kill 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
E) none of the choices are correct

thermal death time (TDT)

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

pasteurization

17. Electrons are ejected from atoms in cells when organisms are exposed to:
A) dessication
B) ultraviolet light
C) ethyl alcohol
D) hydrogen peroxide
E) gamma rays and X rays

gamma rays and X rays

18. Which of the following items are typically irradiated in order to kill microbes?
A) ground beef and other meat and poultry
B) human tissues such as heart valves and skin
C) operating room air
D) surgical gloves
E) all of the choices are correct

all of the choices are correct

19. 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

air

20. Which of the following is not a heavy metal?
A) tincture of iodine
B) Merthiolate
C) silver nitrate solutions
D) zinc
E) Mercurochrome

tincture of iodine

21. All of the following are phenols or phenolics except:
A) Lysol
B) hexachlorophene
C) triclosan
D) cresols
E) chloramines

chloramines

22. 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

vegetative bacteria and fungi

23. Which control method would not be a suitable choice for killing mycobacteria 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

ultraviolet (germicidal) light

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

found in iodophors

25. Which of the following is not used as an antiseptic?
A) iodophor
B) chlorhexidine
C) 3% hydrogen peroxide
D) Merthiolate
E) aqueous glutaraldehyde

aqueous glutaraldehyde

26. Iodophors include:
A) chloramines
B) Betadine
C) tincture of iodine
D) alcohols
E) chlorhexidine

Betadine

27. The compound that is an organic base containing chlorine and two phenolic rings, and is used increasingly for wound degerming, neonatal washs, handscrubbing, and prepping surgical skin sites is:
A) carbolic acid
B) chlorhexidine
C) triclosan
D) formalin
E) quarternary ammonium compounds

chlorhexidine

28. Alcohols:
A) denature proteins when in a 50 - 95% alcohol-water solution
B) disinfect items soaked in alcohol
C) are skin degerming agents
D) at 50% or higher concentrations dissolve cell membrane lipids
E) all of the choices are correct

all of the choices are correct

29. Which is mismatched:
A) sodium hypochlorite - chlorine
B) iodophor - iodine
C) benzalkonium chloride - quaternary ammonium compound
D) Merthiolate - silver
E) formalin - formaldehyde

Merthiolate - silver

30. All of the following are alkylating control agents except:
A) ethylene oxide
B) iodophor
C) glutaraldehyde
D) formaldehyde
E) chlorine dioxide

iodophor

31. The sterilizing gas used in chemiclaves is:
A) ethylene oxide
B) iodophor
C) glutaraldehyde
D) formaldehyde
E) chlorine dioxide

ethylene oxide

32. The chemical agent that produces highly reactive hydroxyl-free radicals and also decomposes to O2 gas is:
A) Cidex
B) cationic detergents
C) hydrogen peroxide
D) chlorhexidine
E) iodophors

hydrogen peroxide

33. All the following act as surfactants except:
A) detergents
B) soaps
C) quats
D) alcohols
E) hypochlorites

hypochlorites

34. Ethylene oxide is:
A) sporicidal
B) only effective with high heat
C) the active agent in household bleach
D) used as an antiseptic against anaerobes
E) a halogen

sporicidal

35. All microbicidal agents are sterilants.
A) True
B) False

False

36. Bacteriostatic agents kill bacterial cells.
A) True
B) False

False

37. The presence of organic matter such as saliva and pus can interfere with the actions of disinfectants.
A) True
B) False

True

38. When a control agent targets the metabolic processes of microbial cells, active younger cells typically die more rapidly than older cells.
A) True
B) False

True

39. A microorganism that is not motile and has stopped metabolizing could be considered dead.
A) True
B) False

False

40. Most microbial contaminants of food are killed at freezing temperatures.
A) True
B) False

False

41. Sonication dislodges debris and saliva from instruments but will not reliably achieve disinfection or sterilization.
A) True
B) False

True

42. Chlorine compounds remain stable and effective in the presence of excess organic matter.
A) True
B) False

False

43. Analine dyes like crystal violet have antimicrobial activity particularly against gram positive bacteria and some fungi.
A) True
B) False

True

44. Alcohols are more effective at inactivating enveloped viruses than naked viruses.
A) True
B) False

True

45. Isopropyl alcohol wiped across a skin site can sterilize it.
A) True
B) False

False

46. Chlorine dioxide and ethylene oxide are sterilizing gases.
A) True
B) False

True

47. _____ heat is more rapidly effective and efficient compared to _____heat.

Moist, Dry

48. Vials of microorganisms that undergo the freeze-drying process called _____ will remain preserved and viable for years.

Lyophilization

49. A method for sterilizing milk, called _____ temperature treatment, uses 134 C for 1 to 2 seconds.

Ultrahigh

50. _____ radiation excites atoms to a higher energy state within molecules such as DNA that then leads to the formation of pyrimidine dimers.

Nonionizing

51. Some microbial control agents are able to _____ cell proteins by breaking bonds that maintain the native state, three-dimensional configuration of the proteins.

Denature

52. _____ is a control method that removes microorganisms rather than inhibiting or killing them.

Filtration

53. _____ is a halogen used in gaseous and liquid form for large scale disinfection of drinking water and sewage.

Chlorine

54. _____ solution was introduced in the late nineteenth century for preventing gonococcal infections in a newborn's eyes after exposure to the mother's infected birth canal.

Silver Nitrate

55. Compare and contrast antisepsis, disinfection, sanitization, and sterilization with regard to techniques used and level of microbial control achieved.

Answers may vary.

56. Discuss the purpose and level of control achieved by pasteurization. Compare the flash and batch methods.

Answers may vary.

57. Explain why boiling water is considered a disinfection, not a sterilization method. List 3 materials commonly disinfected by boiling water.

Answers may vary.

58. Discuss the advantages and disadvantages of irradiating food. Include examples of foods that are irradiated.

Answers may vary.

59. Discuss the technique of filtration as a microbial control method, why it's utilized, and specific materials that are filtered.

Answers may vary.

60. For each item listed below, select a sterilant that you feel is the most suitable and effective for that item. Discuss why you selected each sterilant.
a. plastic Petri dishes to be used for nutrient media
b. glass tubes of bacterial cultures to be discarded
c. sterile milk
d. dozens of reusable glass pipets
e. bone tissue for grafting
f. room air
g. hospital mattresses
h. biopsy tissue for histology analysis
i. plastic respiratory therapy equipment and arthroscopes
j. vaccines

Answers may vary.

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