Question 1

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

Accepted Answer

Sterilization removes all microbes, including endospores, while disinfection eliminates only vegetative cells and some viruses.

Question 2

Which term refers to the mechanical removal of microbes from a surface, such as hand washing?

Accepted Answer

Degerming

Question 3

A bacteriostatic agent will:

Accepted Answer

Inhibit microbial growth without killing the cells.

Question 4

The microbial death rate is important in microbial control because:

Accepted Answer

It allows calculation of the time required to reduce a population by a specific percentage.

Question 5

Which of the following is NOT a primary target for antimicrobial agents?

Accepted Answer

Mitochondria

Question 6

Which group of microbes is most resistant to antimicrobial agents?

Accepted Answer

Bacterial endospores

Question 7

Which environmental condition can decrease the effectiveness of a disinfectant?

Accepted Answer

Presence of organic matter

Question 8

Which biosafety level is appropriate for handling Ebola virus?

Accepted Answer

Biosafety Level 4

Question 9

Which physical method of microbial control is most effective for sterilizing heat-sensitive medical instruments?

Accepted Answer

Filtration

Question 10

What is the main advantage of using moist heat in an autoclave compared to dry heat in an oven?

Accepted Answer

Moist heat is more effective at denaturing proteins and requires less time.

Question 11

Which equation represents the decimal reduction time (D) in microbial control?

Accepted Answer

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

Question 12

Why are Bacillus endospores used in sterilization techniques?

Accepted Answer

They are highly resistant and serve as a standard to test sterilization effectiveness.

Question 13

Which of the following best describes pasteurization?

Accepted Answer

A process that reduces microbial numbers without sterilizing the product.

Question 14

Which method is most effective for preserving microbial cultures for long periods?

Accepted Answer

Lyophilization

Question 15

How do hypertonic solutions control microbial growth?

Accepted Answer

By causing water to leave the cell, leading to plasmolysis.

Question 16

Which type of radiation is most effective for sterilizing medical equipment?

Accepted Answer

Ionizing radiation

Question 17

Why are solutions of 70% to 90% alcohol more effective as antimicrobial agents than pure alcohol?

Accepted Answer

Water is required for protein denaturation.

Question 18

Which of the following is a disadvantage of gaseous agents for microbial control?

Accepted Answer

They are highly toxic and potentially carcinogenic.

Question 19

Which enzyme is used to remove prions from medical instruments?

Accepted Answer

Protease

Question 20

Which method is used to measure the effectiveness of disinfectants and antiseptics by comparing the zone of inhibition?

Accepted Answer

Disk-diffusion method

Ch 9 - Controlling Microbial Growth in the Environment: Study Guide

Study Guide - Practice Questions