Mutant bacteria can be detected by selecting or testing for an altered phenotype by which of the following methods?
a. Neutral selection – selecting mutant cells on the basis of antibody production.
b. Positive (direct) selection – detection of mutant cells by rejection of the unmutated parental cells.
c. Negative (indirect) selection – selection of cells that cannot perform a certain function using replica plating.
d. Both a and b.
e. Both b and c.
1.
Which of the following substances can sterilize?
a. Alcohol
b. Phenolics
c. Ethylene oxide
d. Chlorine
e. Soap
2.
Which of the following substances is used for surgical hand scrubs?
a. Phenol
b. Chlorine bleach
c. Chlorhexidine
d. Soap
e. Glutaraldehyde
3.
Place the following surfactants in order from the overall most effective to the least effective antimicrobial activity:
1-Soap; 2-Acid-anionic detergent; 3-Quats.
a. 1, 2, 3
b. 1, 3, 2
c. 2, 1, 3
d. 3, 2, 1
e. 3, 1, 2
4.
The antimicrobial activity of chlorine when added to water, is due to which of the following?
a. The formation of hypochlorous acid
b. The formation of hydrochloric acid
c. The formation of ozone
d. The formation of free O
e. Disruption of the plasma membrane
5.
Iodophors differ from iodine (I2) in that iodophors
a. Don't stain.
b. Are less irritating.
c. Are longer lasting.
d. Are combined with an organic molecule.
e. All of the above.
6.
Which of the following does NOT achieve sterilization?
a. Dry heat
b. Pasteurization
c. Autoclave
d. Peracetic acid
e. Ethylene oxide
7.
Which of these disinfectants acts by damaging lipids in the plasma membrane of microorganisms?
a. Organic acids
b. Aldehydes
c. Heavy metals
d. Halogens
e. Phenolics
8.
Which of the following disinfectants react with or disturb the microbial plasma membrane, causing its cellular contents to leak out?
a. Alcohols
b. Acid-Anionic Sanitizer
c. QUATS
d. Triclosan
e. All of these
9.
Which of the following is NOT used to disinfect water?
a. Ozone
b. Detergents
c. Chlorine
d. Copper sulfate
10.
Glutaraldehyde is considered one of the most effective disinfectants for hospital use. Which of the following statements about glutaraldehyde is false?
a. It is irritating
b. Is sporicidal
c. Acts rapidly
d. Is not hampered by organic material
e. Attacks all microorganisms
11.
Which concentration of ethanol is the most effective bactericide?
a. 100%
b. 70%
c. 50%
d. 40%
e. 30%
12.
Which of the following is NOT used to preserve foods?
a. Nisin
b. Sodium nitrite
c. Gaseous chemosterilizers
d. Organic acids
13.
Which of the following chemical antimicrobials is useful against anaerobic bacteria in deep wounds?
a. Formalin
b. Benzoyl peroxide
c. Iodine
d. Cresol
e. 70% ethanol
14.
Why are strictly anaerobic bacteria highly susceptible to oxidizing agents?
a. They cannot prevent free radicals of oxygen from reacting with vital cellular components.
b. They do not possess the genes encoding neutralizing enzymes for highly reactive forms of oxygen.
c. The oxygen released kills them.
d. All of the above.
15.
In some situations it is better to use heat sterilization methods over chemical disinfectants. Why is this?
a. Organic materials present may interfere with the action of the disinfectant.
b. Sometimes the disinfectant cannot make easy contact with the microbes.
c. Some chemical disinfectants can corrode materials.
d. The pH of the material may not be optimal for potent disinfectant effectiveness.
e. All of the above are true.
appreciate the help
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