MCB 100 Final Exam Questions and 100% Correct Answers
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Course
MCB 100
Institution
MCB 100
An autoclave is able to achieve temperatures higher than that of boiling water_____
a. by increasing the temp higher than boiling water. b. by increasing the time of exposure of boiling water. c. by increasing pressure. d. by decreasing the volume of liquid. c. by increasing pressure.
When microb...
MCB 100 Final Exam Questions and
100% Correct Answers
An autoclave is able to achieve temperatures higher than that of boiling water_____
a. by increasing the temp higher than boiling water.
b. by increasing the time of exposure of boiling water.
c. by increasing pressure.
d. by decreasing the volume of liquid. ✅c. by increasing pressure.
When microbial control methods are used, microbes are destroyed at a constant rate;
there is no instantaneous death of all the microbes present. This microbial death rate is
influenced by all of the following factors except______
a. the stability of the proteins in the bacteria.
b. the number of microbes that are present.
c. the length of time of exposure to the treatment.
d. the microbial physiological characteristics.
e. the toxins and metabolites produced by the bacteria. ✅e. the toxins and metabolites
produced by the bacteria.
Which of the following statements about pasteurization is NOT true?
a. pasteurization involves flash heating to 135C for about a minute.
b. pasteurization is a method of sterilization that kills microbes present in food.
c.pasteurization reduces the microbial load in heat-sensitive liquids.
d. pasteurization increases the shelf life of perishable liquids.
e. pasteurization controls microbes that cause spoilage, sucha as E. coli and
Salmonella ✅b. pasteurization is a method of sterilization that kills microbes present in
food.
Determine which of the following statements is true or false, then select the correct
answer sequence;
1. The term "antimicrobial agent" includes: antibiotics, fungicidal, and antiparastitic
agents.
2. Bacteriostatic agents inhibit bacterial growth, but do no necessarily kill the organisms
against which they are directed.
3. Agents that inhibit bacterial cell wall biosynthesis can be bactericidal.
4. Antiseptics are sufficiently nontoxic that they can be applied to skin.
a. T, T, T, T
b. F, F, F, F
, c. F, T, T, F
d. T,T, F, F
e. T, F, T, F ✅a. T, T, T, T
Moist heat kills microbes faster than dry heat because _____
a. hot air causes the cells to release water which evaporates and cools them off and
keep them alive longer.
b. hot water makes the cell swell and burst, while hot air just shrinks the cells.
c. moist heat denatures protein and nucleic acid structures and disrupting cell
membranes, which takes less time to kills cells than removing water by dry heat and
killing cells through oxidation reactions.
d. hot air removes the water from the cells but does not kill them right away. ✅c. moist
heat denatures protein and nucleic acid structures and disrupting cell membranes,
which takes less time to kills cells than removing water by dry heat and killing cells
through oxidation reactions.
Oxidizing agents such as chlorine or hydrogen peroxide are particularly effective against
_____ organisms.
a. aerobic
b. anaerobic
c. faculative aerobic
d. microaerophilic ✅b. anaerobic
Which of the following antimicrobial agents is the most toxic to humans?
a. ethylene oxide
b. chloramines
c. 70% alcohol
d. quaternary ammonium
e. iodine ✅a. ethylene oxide
Which of the following is used to sterilize items that should not, or cannot, be exposed
to heat or water?
a. triclosan
b. formaldehyde
c. hydrogen peroxide
d. ethylene oxide
e. calcium hypochlorite ✅d. ethylene oxide
70% alcohol and quaternary ammonium compounds are effective against:
a. non-enveloped viruses
b. protozoan cysts
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