Question 1

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

Accepted Answer

Sterilization destroys all microbial life, including endospores, while disinfection destroys most microbial life but not endospores.

Question 2

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

Accepted Answer

Autoclaving at 121 \degree C and 15 psi for 20 minutes

Question 3

Which of the following microbial forms is the most resistant to physical and chemical control agents?

Accepted Answer

Prions

Question 4

A food processing plant needs to decontaminate heat-sensitive liquid vitamins. Which method is most suitable?

Accepted Answer

Filtration through a membrane with pore size $$0.22\ \mu m$$

Question 5

Which of the following statements about alcohols as antimicrobial agents is correct?

Accepted Answer

Alcohols are more effective at 70\% concentration than at 100\% because water is needed for protein coagulation.

Question 6

A laboratory technician needs to sterilize a heat-sensitive plastic Petri dish. Which method should be used?

Accepted Answer

Ionizing radiation (gamma rays)

Question 7

Which of the following is NOT a desirable quality of an antimicrobial chemical?

Accepted Answer

It should be inactivated quickly by organic matter.

Question 8

Which of the following best explains why high concentrations of salt or sugar preserve foods?

Accepted Answer

They create a hypertonic environment, causing plasmolysis in bacteria.

Question 9

A nurse is cleaning a wound with 3\% hydrogen peroxide. What is the primary mechanism by which hydrogen peroxide acts as a germicide?

Accepted Answer

Oxidation of cellular components

Question 10

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

Accepted Answer

Moist heat requires lower temperatures and shorter exposure times than dry heat to achieve sterilization.

Question 11

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

Accepted Answer

Prions \u003e Bacterial endospores \u003e Fungal spores \u003e Gram-positive bacteria

Question 12

A researcher is using UV radiation to disinfect a laboratory bench. Which of the following is a limitation of UV radiation for this purpose?

Accepted Answer

UV radiation does not penetrate well through solids or even liquids, so only exposed surfaces are disinfected.

Question 13

Which of the following best describes the action of surfactants (such as detergents) on microbial cells?

Accepted Answer

They disrupt the lipid bilayer of cell membranes, creating leaky spots.

Question 14

A patient is prescribed a bacteriostatic agent for a bacterial infection. What is the expected effect of this agent?

Accepted Answer

It will inhibit the growth and reproduction of bacteria without killing them.

Question 15

Which of the following is a true statement about the use of phenol (carbolic acid) in modern disinfectants like Lysol?

Accepted Answer

Modern Lysol products do not contain phenol; they use quaternary ammonium compounds instead.

Question 16

Which of the following factors does NOT affect the rate of microbial death when using a chemical agent?

Accepted Answer

The color of the chemical agent

Question 17

A batch of milk is pasteurized using the flash method. What are the typical time and temperature conditions for this process?

Accepted Answer

$$71.6\ ^\circ C$$ for 15 seconds

Question 18

Which of the following is the main reason why boiling water is not considered a reliable method of sterilization?

Accepted Answer

Boiling does not destroy bacterial endospores.

Question 19

Which of the following is a correct application of a high-level germicide?

Accepted Answer

Sterilizing surgical implants that cannot be heat-sterilized

Physical and Chemical Control of Microbes: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard