Question 1

Which of the following best describes the process of sterilization?

Accepted Answer

Removing and destroying all microbial life

Question 2

A hospital is preparing surgical instruments for use. Which method would ensure the destruction of all organisms, including endospores, on these instruments?

Accepted Answer

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

Question 3

Which of the following terms refers to the mechanical removal of microbes from a limited area, such as when preparing skin for an injection?

Accepted Answer

Degerming

Question 4

A food processing plant uses a chemical to lower microbial counts on eating utensils to safe public health levels. This process is best described as:

Accepted Answer

Sanitization

Question 5

Which of the following is NOT a factor that affects the effectiveness of antimicrobial treatments?

Accepted Answer

Color of the microorganism

Question 6

The decimal reduction time (DRT) is defined as:

Accepted Answer

The time required to kill 90\% of a microbial population at a given temperature

Question 7

Which of the following best explains why 70\% ethanol is more effective as a disinfectant than 95\% ethanol?

Accepted Answer

Water is required for protein denaturation, which is the main mode of action for ethanol

Question 8

A researcher is using a membrane filter to sterilize a solution that cannot be heated. What is the smallest pore size that will reliably remove most bacteria from the solution?

Accepted Answer

$$0.22\ \mu m$$

Question 9

Which of the following physical methods of microbial control works primarily by causing plasmolysis through a hypertonic environment?

Accepted Answer

Osmotic pressure

Question 10

Ionizing radiation kills cells by which of the following mechanisms?

Accepted Answer

Ionizing water to create reactive hydroxyl radicals that damage DNA

Question 11

A hospital is evaluating a new disinfectant using the disk-diffusion method. What result would indicate the disinfectant is effective?

Accepted Answer

A clear zone of inhibition around the disk

Question 12

Which of the following chemical agents is classified as a sterilant and is used for heat-sensitive medical equipment?

Accepted Answer

Ethylene oxide

Question 13

Which of the following statements about aldehydes is correct?

Accepted Answer

They inactivate proteins by cross-linking with functional groups such as $$-NH_2$, -OH$, -$$COOH$$, and -SH$

Question 14

Which of the following is a correct match between a chemical agent and its preferred use?

Accepted Answer

Silver nitrate: prevention of ophthalmia neonatorum

Question 15

A patient is treated with a chemical that inhibits metabolism in molds found in acidic foods. Which chemical is most likely being used?

Accepted Answer

Sorbic acid

Question 16

Which of the following best describes the action of quaternary ammonium compounds (quats)?

Accepted Answer

They are cationic agents that denature proteins and disrupt plasma membranes

Question 17

A laboratory is testing the effectiveness of a new disinfectant. The initial population is $$1 	imes 10^6$ cells. If the decimal reduction time (DRT) is 1 minute, how many cells will remain after 3 minutes of treatment?

Accepted Answer

$$1 	imes 10^3$

Question 18

Which of the following statements about the use of plasma as a sterilization method is correct?

Accepted Answer

Plasma generates free radicals that destroy microbes and is used for sterilizing tubular instruments

Question 19

Which of the following is a real-world example of the use of supercritical fluids in microbial control?

Accepted Answer

Sterilization of medical implants using $$CO_2 at $$high pressure and temperature

Question 20

Which of the following best explains why nonionizing radiation (such as UV light at 260 nm) is effective at killing microbes?

Accepted Answer

It causes the formation of thymine dimers in DNA, leading to lethal mutations

Chapter 7: The Control of Microbial Growth – Comprehensive Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards