Question 1

Which of the following best describes antisepsis?

Accepted Answer

The reduction of the number of microorganisms on a living tissue.

Question 2

Ignaz Semmelweis is historically significant in microbiology because he:

Accepted Answer

Pioneered the use of antiseptic handwashing to reduce maternal mortality.

Question 3

Which of the following is an example of a physical method of microbial control?

Accepted Answer

Flaming laboratory equipment.

Question 4

A disinfectant kills 90% of bacteria every minute. If you start with $$1,000,000$$ bacteria, how many minutes will it take to reduce the population below $$1$$ bacterium?

Accepted Answer

7 minutes

Question 5

Which term describes an agent that inhibits the growth of bacteria but does not kill them?

Accepted Answer

Bacteriostatic

Question 6

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

Accepted Answer

Moist heat penetrates cells and denatures proteins more efficiently.

Question 7

Which of the following is NOT a drawback of using phenol as a disinfectant?

Accepted Answer

It is odorless and colorless.

Question 8

Which chemical agent is commonly used to sterilize heat-sensitive medical equipment?

Accepted Answer

Ethylene oxide gas

Question 9

What is the main reason prions are classified as the most resistant to microbial control methods?

Accepted Answer

They are not affected by standard sterilization techniques.

Question 10

Which of the following best explains why increasing pressure in an autoclave allows water to reach temperatures above its normal boiling point?

Accepted Answer

Increasing pressure prevents steam from escaping, allowing temperature to rise above $$100^ C.$$

Question 11

Which of the following is a limitation of using boiling as a method of sterilization?

Accepted Answer

Boiling does not kill bacterial endospores.

Question 12

Which method is most appropriate for sterilizing a heat-sensitive mattress?

Accepted Answer

Ethylene oxide gas

Question 13

Which of the following is a real-world example of microbial control using osmotic pressure?

Accepted Answer

Preserving jams with high sugar concentration

Question 14

Which of the following statements about filtration is correct?

Accepted Answer

Filtration can be used to sterilize heat-sensitive liquids by removing bacteria.

Question 15

Which of the following is the correct order of microbial resistance from most to least resistant?

Accepted Answer

Prions \u003e Bacterial endospores \u003e Enveloped viruses

Question 16

Which chemical agent works by oxidizing enzymes and is used to sterilize surfaces but is not useful for treating wounds due to the presence of catalase in human cells?

Accepted Answer

Hydrogen peroxide

Question 17

Which biosafety level is appropriate for handling pathogens that do not cause disease in healthy humans?

Accepted Answer

Biosafety Level 1

Question 18

Which of the following is a major drawback of using heavy metals as antimicrobial agents?

Accepted Answer

They are highly toxic to humans.

Question 19

Which of the following best describes the action of surfactants in microbial control?

Accepted Answer

They reduce surface tension, making microbes easier to remove.

Question 20

A hospital needs to sterilize a batch of heat-sensitive plastic syringes. Which method should be used?

Accepted Answer

Ethylene oxide gas

Ch 9 Lecture

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