ch. 7 microbiology

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1

The removal or destruction of ALL forms of microbial life is called

a. sterilization.
b. disinfection.
c. pasteurization.
d. sanitization.

a. sterilization.

2

The destruction of vegetative pathogens is called

a. sanitization.
b. commercial sterilization.
c. disinfection.
d. antisepsis.

c. disinfection.

3

What treatment is intended to lower microbial counts on eating and drinking utensils to safe public health levels?

a. sanitization
b. sterilization
c. pasteurization
d. antisepsis

a. sanitization

4

The absence of significant contamination is called

a. sepsis.
b. bacteriostasis.
c. asepsis.
d. antisepsis.

c. asepsis.

5

Commercial sterilization is a limited heat treatment to destroy

a. Streptococcus pyogenes.
b. Clostridium tetani.
c. Staphylococcus aureus.
d. Clostridium botulinum endospores.

d. Clostridium botulinum endospores.

6

Which of the following BEST describes the pattern of microbial death?

a. The cells in a population die at a constant rate.
b. All the cells in a culture die at once.
c. Not all of the cells in a culture are killed.
d. The pattern varies, depending on the
species.

a. The cells in a population die at a constant rate.

7

The time it takes to kill a microbial population is

a. dependent on heat.
b. proportional to the number of microbes.
c. dependent on life cycle phases.
d. dependent on chemicals.

b. proportional to the number of microbes.

8

Damage to which structure causes cellular components to leak into the surrounding medium?

a. cell wall
b. plasma membrane
c. cytoplasm
d. glycocalyx

b. plasma membrane

9

Which of the following types of bond are NOT important in maintaining the shape of proteins?

a. peptide bonds
b. hydrogen bonds
c. disulfide bonds
d. covalent bonds

a. peptide bonds

10

Which of the following is NOT a factor that influences the effectiveness of antimicrobial treatments?

a. microbial characteristics
b. number of microbes
c. time of day
d. presence of a biofilm

c. time of day

11

To sterilize heat-labile solutions, one should use

a. dry heat.
b. an autoclave.
c. membrane filtration.
d. pasteurization.

c. membrane filtration.

12

Which method kills microorganisms primarily by the coagulation of proteins (denaturation)?

a. filtration
b. radiation
c. desiccation
d. moist heat

d. moist heat

13

The phosphatase test is used to determine whether which one of the following processes was carried out correctly?

a. radiation
b. filtration
c. desiccation
d. pasteurization

d. pasteurization

14

Flaming is one of the simplest methods of

a. pasteurization.
b. dry heat sterilization.
c. moist heat.
d. desiccation.

b. dry heat sterilization.

15

The lowest temperature at which all of the microorganisms in a particular liquid suspension will be killed in 10 minutes is called

a. thermal death point.
b. thermal death time.
c. decimal reduction time.
d. decimal reduction point.

a. thermal death point.

16

Sterilization can be achieved by using

a. alcohol.
b. soap.
c. chlorine.
d. ethylene oxide.

d. ethylene oxide.

17

Which method of evaluating disinfectants is the currently used standard?

a. use-dilution test
b. use-diffusion test
c. disk-dilution test
d. disk-diffusion test

a. use-dilution test

18

Which of the following is used on environmental surfaces, instruments, skin surfaces, and mucous membranes?

a. nitrites
b. ozone
c. phenolics
d. ethylene oxide

c. phenolics

19

Ethanol can be used as an effective bactericide when used at a concentration of

a. 70%.
b. 50%.
c. 40%.
d. 100%.

a. 70%.

20

Which of the following is NOT used to preserve foods?

a. sulfur dioxide
b. sodium nitrite
c. potassium sorbate
d. biguanides

d. biguanides

21

Which of the following is the MOST useful for disinfecting medical instruments?

a. quats
b. chlorine
c. phenol
d. benzoic acid

a. quats

22

Which of the following is/are used to mechanically remove microbes through scrubbing?

a. alcohol
b. biguanides
c. detergents
d. quats

c. detergents

23

Which chemical agents cause a disruption of the plasma membrane and denaturation of enzymes?

a. phenolics
b. biguanides
c. heavy metals
d. halogens

a. phenolics

24

Which agents cause denaturation of enzymes and other essential proteins?

a. aldehydes
b. heavy metals
c. peroxygens
d. nitrates

b. heavy metals

25

What chemical is used to prevent molds from growing in cheese and soft drinks?

a. sorbic acid
b. calcium propionate
c. sulfur dioxide
d. sodium nitrate

a. sorbic acid

26

What chemical selectively inhibits certain iron-containing enzymes of Clostridium botulinum?

a. sodium benzoate
b. sodium nitrate
c. sodium nitrite
d. calcium propionate

c. sodium nitrite