Question 1

Which of the following best describes the difference between a disinfectant and an antiseptic?

Accepted Answer

A disinfectant is used on inanimate objects, while an antiseptic is used on living tissue.

Question 2

A hospital is experiencing an outbreak of Clostridioides difficile, an endospore-forming bacterium. Which method would be most effective for sterilizing surgical instruments to prevent further infections?

Accepted Answer

Autoclaving at 121^\circ C and 15 psi for 15 minutes

Question 3

Which of the following statements about sterilization is TRUE?

Accepted Answer

Sterilization is microbicidal and destroys all microbial life.

Question 4

Which physical method of microbial control works by denaturing proteins and altering membranes, and is only suitable for heat-stable materials?

Accepted Answer

Heat

Question 5

A laboratory technician needs to sterilize a heat-sensitive plastic instrument. Which method is most appropriate?

Accepted Answer

Ethylene oxide gas

Question 6

Which of the following chemical agents works by oxidizing molecules and is commonly used for disinfecting water?

Accepted Answer

Halogens

Question 7

A juice processing plant wants to reduce microbial load without sterilizing the juice. Which method should they use?

Accepted Answer

Pasteurization

Question 8

Which of the following is a microbiostatic method?

Accepted Answer

Refrigeration

Question 9

Which physical method is most suitable for removing microbes from heat-sensitive solutions such as antibiotics?

Accepted Answer

Filtration using membrane filters

Question 10

Which of the following statements about irradiation is correct?

Accepted Answer

Ionizing radiation (gamma and x-rays) damages DNA and can sterilize medical equipment.

Question 11

A microbiologist wants to sterilize a glass pipette. Which method is most appropriate?

Accepted Answer

Autoclaving

Question 12

Which of the following is NOT a chemical method for controlling microbial growth?

Accepted Answer

Autoclaving

Question 13

Which of the following best describes the action of peroxygens as a chemical control method?

Accepted Answer

They produce free radicals that damage cellular components.

Question 14

A hospital room is being cleaned after a patient with a contagious disease. Which method would be most appropriate for disinfecting the surfaces?

Accepted Answer

Using a hospital-grade disinfectant

Question 15

Which of the following is a limitation of using heat as a method of microbial control?

Accepted Answer

It can only be used on heat-stable materials.

Question 16

Which of the following methods would be LEAST effective for sterilizing a solution containing heat-sensitive vitamins?

Accepted Answer

Autoclaving

Question 17

Which of the following is TRUE regarding the use of alcohols as chemical control agents?

Accepted Answer

They are effective at dissolving membranes and denaturing proteins.

Question 18

A researcher needs to sterilize a nutrient broth without altering its chemical composition. Which method should be used?

Accepted Answer

Filtration

Question 19

Which of the following is an example of a microbicidal treatment?

Accepted Answer

Autoclaving

Question 20

Which of the following best explains why HEPA filters are used in hospital air systems?

Accepted Answer

They physically remove microbes from the air.

Control of Microbial Growth: Physical and Chemical Methods

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