Question 1

Which of the following best describes the process of sterilization?

Accepted Answer

A process that destroys all viable microbes, including viruses and endospores.

Question 2

A surgeon is preparing for an operation and uses a chemical agent on their hands. Which term best describes this agent?

Accepted Answer

Antiseptic

Question 3

Rank the following microorganisms from least resistant to most resistant to chemical control agents: Gram-positive bacteria, prions, endospores of bacteria, viruses with lipid envelopes.

Accepted Answer

Viruses with lipid envelopes \u003c Gram-positive bacteria \u003c Endospores of bacteria \u003c Prions

Question 4

Which physical method of microbial control is most effective for sterilizing heat-sensitive liquids such as vaccines?

Accepted Answer

Membrane filtration

Question 5

Which chemical agent is most effective against Mycobacteria but has poor activity against endospores?

Accepted Answer

Alcohols

Question 6

A hospital uses ethylene oxide gas to sterilize surgical instruments. What is the primary mechanism by which this gas kills microbes?

Accepted Answer

Alkylation, which cross-links nucleic acids and proteins

Question 7

Which of the following statements about moist heat sterilization is correct?

Accepted Answer

It denatures proteins and is the best way to achieve sterilization for most materials.

Question 8

A microbiologist wants to sterilize a heat-sensitive solution. Which method should they use?

Accepted Answer

Filtration

Question 9

Which of the following is a disadvantage of using gaseous sterilants such as ethylene oxide?

Accepted Answer

They are potentially carcinogenic and highly explosive.

Question 10

Which chemical agent is commonly used as a topical cream on burns and acts by denaturing proteins?

Accepted Answer

Silver sulfadiazine

Question 11

A sample contains $$1,000,000$$ bacteria. If the death rate is $$90	ext{\%}$$ per minute, how many bacteria remain after $$2$$ minutes?

Accepted Answer

$$10,000$$

Question 12

Which of the following is true regarding the effectiveness of chemical antimicrobials against endospores and Mycobacteria?

Accepted Answer

Glutaraldehyde is fair against endospores and good against Mycobacteria.

Question 13

Which physical method of microbial control is bacteriostatic rather than bactericidal?

Accepted Answer

Refrigeration

Question 14

Why is hydrogen peroxide not useful for treating open wounds?

Accepted Answer

Catalase in tissues breaks it down rapidly.

Question 15

Which of the following best explains why slow freezing is more effective than quick freezing for microbial control?

Accepted Answer

Slow freezing allows ice crystals to form, which damage cell structures.

Question 16

A food processing plant wants to reduce spoilage organisms and pathogens in milk without destroying its flavor. Which method should be used?

Accepted Answer

Pasteurization

Question 17

Which chemical agent is most likely to remain active for prolonged periods and is commonly used in health care settings, but has a disagreeable odor and possible side effects?

Accepted Answer

Phenol

Question 18

Which of the following is a major disadvantage of dry heat sterilization compared to moist heat sterilization?

Accepted Answer

It requires higher temperatures and longer exposure times.

Question 19

Which of the following is the primary cellular structure affected by surfactants such as quaternary ammonium compounds?

Accepted Answer

Plasma membrane

Question 20

A laboratory is testing the efficacy of a new disinfectant using the disk-diffusion method. What result indicates the disinfectant is effective?

Accepted Answer

A clear zone of inhibition around the disk

Control of Microbial Growth: Terminology, Methods, and Microbial Resistance

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