Question 1

Which of the following best describes the process of sterilization?

Accepted Answer

The destruction of all microorganisms and viruses on or in an object

Question 2

A hospital is preparing surgical instruments for use. Which method would be most appropriate to ensure all microbial life, including endospores, is destroyed?

Accepted Answer

Autoclaving at 121°C, 15 psi, for 15 minutes

Question 3

Which of the following statements about the microbial death curve is correct?

Accepted Answer

A constant percentage of the extant population is killed each minute

Question 4

If a microbial population of $$10^6$$ cells is exposed to a treatment with a decimal reduction time (D) of 2 minutes, how many cells will remain after 6 minutes?

Accepted Answer

$$10^3$$

Question 5

Which of the following organisms is most resistant to antimicrobial agents?

Accepted Answer

Prions

Question 6

Why is moist heat generally more effective than dry heat for sterilization?

Accepted Answer

Moist heat denatures proteins and destroys membranes more efficiently

Question 7

A solution contains $$10^6$$ bacteria. If the death rate is such that 90% of the population is killed every minute, how many bacteria remain after 3 minutes?

Accepted Answer

$$10^3$$

Question 8

Which of the following is an example of degerming?

Accepted Answer

Washing hands with soap and water

Question 9

Which physical method is best for sterilizing heat-sensitive solutions such as vaccines?

Accepted Answer

Filtration through a membrane filter with a pore size of 0.22 µm

Question 10

Which chemical agent is most appropriate for sterilizing medical equipment that cannot withstand heat or moisture?

Accepted Answer

Gaseous agents such as ethylene oxide

Question 11

Why are Bacillus endospores commonly used as sterility indicators in autoclave procedures?

Accepted Answer

They are among the most resistant forms of microbial life

Question 12

Which of the following best explains why milk can still spoil after pasteurization?

Accepted Answer

Pasteurization does not kill all heat-tolerant microbes

Question 13

Which of the following is a limitation of using hydrogen peroxide as an antiseptic for open wounds?

Accepted Answer

Catalase in tissues breaks down hydrogen peroxide

Question 14

A laboratory technician needs to reduce the microbial load on eating utensils to safe levels. Which process should be used?

Accepted Answer

Sanitization

Question 15

Which of the following statements about quaternary ammonium compounds (quats) is correct?

Accepted Answer

They are low-level disinfectants that disrupt cellular membranes

Question 16

Which of the following best describes the action of ionizing radiation on microbial cells?

Accepted Answer

It creates ions that disrupt hydrogen bonding and denature DNA

Question 17

A food processing plant wants to extend the shelf life of strawberries without using heat. Which method would be most effective?

Accepted Answer

Ionizing radiation

Question 18

Which of the following is a correct statement about the use-dilution test?

Accepted Answer

It determines the effectiveness of disinfectants by measuring the ability to prevent microbial growth on metal cylinders

Question 19

Which of the following best explains why denaturation of proteins kills microbial cells?

Accepted Answer

Denatured proteins lose their functional 3-D shape, halting essential cellular processes

Question 20

Which of the following environmental factors can decrease the efficacy of chemical disinfectants?

Accepted Answer

Presence of organic materials

Controlling Microbial Growth in the Environment

Study Guide - Practice Questions

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