Question 1

Which of the following best describes the process of sterilization?

Accepted Answer

The removal or destruction of all microbial life

Question 2

A hospital technician is preparing surgical instruments for use. Which method would ensure the destruction of all organisms and endospores on the instruments?

Accepted Answer

Autoclaving at 121 \degree C and 15 psi for 15 minutes

Question 3

Which of the following terms refers to the inhibition, but not killing, of microbes?

Accepted Answer

Bacteriostasis

Question 4

Why does a solution containing 1,000,000 bacteria take longer to sterilize than one containing 500,000 bacteria, assuming the same rate of killing?

Accepted Answer

The larger population requires more time for each cell to be exposed to the agent

Question 5

Which of the following is NOT a factor that affects the effectiveness of a disinfectant?

Accepted Answer

Color of the disinfectant

Question 6

A chemical agent that damages plasma membranes would likely have which of the following effects on human cells?

Accepted Answer

Potential toxicity, since human cells also have plasma membranes

Question 7

Which physical method of microbial control is most appropriate for sterilizing heat-sensitive solutions such as certain vitamins or antibiotics?

Accepted Answer

Filtration

Question 8

Which of the following statements about decimal reduction time (DRT) is correct?

Accepted Answer

It is the time required to kill 90% of a microbial population at a given temperature

Question 9

Which chemical agent is considered a sporicide and is effective against both endospores and mycobacteria?

Accepted Answer

Glutaraldehyde

Question 10

A laboratory is testing the effectiveness of a new disinfectant using the disk-diffusion method. What result would indicate the disinfectant is effective?

Accepted Answer

A large zone of inhibition around the disk

Question 11

Which of the following best explains why high concentrations of salt or sugar can preserve food?

Accepted Answer

They create a hypertonic environment causing plasmolysis

Question 12

Which of the following is a correct statement about the action of ionizing radiation on microbial cells?

Accepted Answer

It ionizes water to create reactive hydroxyl radicals

Question 13

Which of the following is a reason why large containers require longer autoclave sterilization times than small containers?

Accepted Answer

Heat penetrates more slowly into larger volumes

Question 14

Which of the following chemical agents is used as an antiseptic for skin disinfection before surgery?

Accepted Answer

Betadine (povidone-iodine)

Question 15

A food manufacturer wants to prevent the germination of endospores in canned meats. Which chemical additive should be used?

Accepted Answer

Nitrites and nitrates

Question 16

Which of the following best describes the mechanism of action of quaternary ammonium compounds (quats)?

Accepted Answer

They denature proteins and disrupt plasma membranes

Question 17

A patient is treated with a chemical agent that inactivates proteins by cross-linking with functional groups such as $$-NH_2$, -OH$, -$$COOH$$, and -SH$. Which agent is most likely being used?

Accepted Answer

Glutaraldehyde

Question 18

Which of the following statements about alcohols as disinfectants is correct?

Accepted Answer

They require water to be effective

Question 19

Which of the following is a major advantage of glutaraldehyde over other chemical disinfectants?

Accepted Answer

It is one of the few liquid chemical sterilizing agents

Question 20

Which of the following best explains why surface-active agents are attractive to the dairy industry?

Accepted Answer

They are non-toxic and remove microbes by emulsification

The Control of Microbial Growth: Microbiology Study Notes

Study Guide - Practice Questions

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