Question 1

Which of the following best describes the difference between sterilization and commercial sterilization?

Accepted Answer

Sterilization eliminates all forms of microbial life, including endospores, while commercial sterilization targets only pathogens and spoilage organisms in food products.

Question 2

A surgeon prepares for an operation by scrubbing hands and using sterile gloves. Which term best describes this practice?

Accepted Answer

Aseptic technique

Question 3

Which suffix indicates an agent that kills microbes, and which indicates an agent that inhibits their growth?

Accepted Answer

‘-cide’ means killing; ‘-static’ means inhibiting growth.

Question 4

Which of the following is most resistant to chemical controls due to its outer membrane structure?

Accepted Answer

Gram-negative bacteria

Question 5

A microbiologist wants to determine the effectiveness of a new disinfectant. Which method should they use?

Accepted Answer

Disk diffusion method

Question 6

Which equation best represents the decimal reduction time ($$D$$), the time required to reduce a microbial population by 90% at a given temperature?

Accepted Answer

$$D = \frac{t}{\log_{10}(N_0$/N)$$}

Question 7

Which physical method is most appropriate for sterilizing heat-sensitive solutions, such as vaccines?

Accepted Answer

Filtration

Question 8

Which of the following best describes the mechanism of action for ionizing radiation?

Accepted Answer

It causes the formation of free radicals that damage cellular DNA.

Question 9

Why is alcohol most effective as a disinfectant when diluted to about 70% concentration?

Accepted Answer

Water is required to denature proteins and facilitate cell membrane disruption.

Question 10

Which chemical control agent is commonly used to sterilize medical equipment and is effective against endospores?

Accepted Answer

Ethylene oxide

Question 11

A food manufacturer uses sodium nitrite in processed meats. What is the primary purpose of this additive?

Accepted Answer

To inhibit the growth of Clostridium botulinum

Question 12

Which of the following best explains the principle of oligodynamic action as it relates to heavy metals?

Accepted Answer

Small amounts of heavy metals exert antimicrobial effects by denaturing proteins.

Question 13

Which of the following is a mechanism by which chlorine acts as a disinfectant?

Accepted Answer

It forms hypochlorous acid ($$\mathrm{HOCl}) in $$water, which oxidizes cellular components.

Question 14

Which of the following is NOT a mechanism by which moist heat sterilization kills microbes?

Accepted Answer

Formation of free radicals

Question 15

A hospital uses HEPA filters in its ventilation system. What is the primary function of these filters?

Accepted Answer

To remove airborne microbes and particles larger than $$0.3\ \mu m$$

Question 16

Which of the following best describes the mechanism of action for aldehydes as chemical control agents?

Accepted Answer

They cross-link proteins and nucleic acids, inactivating microbial cells.

Question 17

Which physical method of microbial control is least effective against endospores?

Accepted Answer

Pasteurization

Question 18

Which of the following is a limitation of using microwaves to control microbial growth?

Accepted Answer

Microwaves heat unevenly, leading to survival of some microbes.

Question 19

Which of the following best describes the mechanism of action for phenol as a disinfectant?

Accepted Answer

It disrupts plasma membranes and denatures proteins.

Question 20

A laboratory technician is tasked with reducing microbial contamination on skin before an injection. Which term best describes this process?

Accepted Answer

Degerming

Control of Microbial Growth: Principles and Methods

Study Guide - Practice Questions

Study Guide - Flashcards