31. What is the length of time required for a chemical agent (or condition) to kill 90% of a microbial population?
(A) death time (B) partial sterilization time
(C)killing period (D)decimal reduction time
(E) sanitation time
32. The process by which allliving cells, spores, and viruses are destroyed on an object is called
(A) sterilization. (B) disinfection.
(C)antisepsis. (D)sanitation.
(E) all of the above
33. Some endospores can survive an autoclave treatment. Based on the conditions of an autoclave, endospores are _____ and ____ compared to their vegetative cell counterparts.
(A) barophilic / psychrophilic (B) acidophilic / mesophilic
(C)halophilic / barotolerant (D)alkaliphilic / aerotolerant
(E) barotolerant / thermophilic
34. A woman with digestive problems attempts to restore normal gut microflora by ingesting yogurt containing live, active cultures. This is an example of using
(A) antibiotics. (B) probiotics.
(C)phage therapy. (D)bioremediation.
(E) disinfectants.
35. What is the relationship between osmolarity and water activity?
(A) There is a negative correlation; as osmolarity increases water activity also increases.
(B) There is a positive correlation; as osmolarity increases water activity decreases.
(C)There is no correlation between osmolarity and water activity.
(D)There is a negative correlation; as osmolarity increases water activity decreases.
(E) There is a positive correlation; as osmolarity increases water activity also increases.
36. Which of the following enzymes generates hydrogen peroxide when destroying a reactive oxygen species?
(A) superoxide dismutase (B) catalase
(C)peroxidase (D)ATP synthetase
(E) NADH dehydrogenase
37. A genetic program leading to the production of chaperones, proteases, and enzymes that change membrane lipid composition, in response to adverse environmental conditions, is known as the
(A) irradiation response. (B) high pressure response.
(C)halophilic response. (D)Arrhenius response.
(E) heat shock response.
38. Changes in environmental temperature may
(A) affect the fluidity of bacterial membranes.
(B) affect the motion of macromolecules within the bacterial cell.
(C)affect the stability of molecules within bacteria.
(D)all of the above.
(E) none of the above.
39. Within temperatures allowable for growth, higher temperatures usually lead to
(A) higher growth rates. (B) slower growth rates.
(C)no effect on growth rates. (D)unpredictable growth rates.
(E) variable effect, depending on the species.
40. Which of the following sentences is correct?
(A) Sanitation kills all cells, spores, and viruses on an object, sterilization removes pathogens from inanimate surfaces, and disinfection removes pathogens from the surface of living tissues.
(B) Disinfection kills all cells, spores, and viruses on an object, antisepsis removes pathogens from inanimate surfaces, and sterilization removes pathogens from the surface of living tissues.
(C)Sterilization kills all cells, spores, and viruses on an object, disinfection removes pathogens from inanimate surfaces, and antisepsis removes pathogens from the surface of living tissues.
(D)Disinfection kills all cells, spores, and viruses on an object, sterilization removes pathogens from inanimate surfaces, and antisepsis removes pathogens from the surface of living tissues.
(E) Sanitation kills all cells, spores, and viruses on an object, sterilization removes pathogens from inanimate surfaces, and antisepsis removes pathogens from the surface of living tissues.
