$$N_t = N_0$ \times e$$^{-kt}$$

Question 1

Which of the following microbial forms is MOST resistant to antimicrobial agents?

Accepted Answer

Bacterial endospores

Question 2

A hospital wants to sterilize heat-sensitive medical equipment. Which method is MOST appropriate?

Accepted Answer

Gaseous agents

Question 3

Which chemical method of microbial control is most effective in the presence of organic matter and remains active for prolonged periods?

Accepted Answer

Phenol and phenolics

Question 4

Why is moist heat generally more effective than dry heat for sterilization?

Accepted Answer

Moist heat denatures proteins and destroys cytoplasmic membranes more efficiently

Question 5

Which biosafety level is appropriate for handling microbes that cause severe or fatal disease?

Accepted Answer

Biosafety Level 4

Question 6

A scientist is testing a new disinfectant using the use-dilution test. What is the main criterion for determining the disinfectant's effectiveness?

Accepted Answer

The ability to prevent growth at the highest dilution

Question 7

Which of the following statements about ionizing radiation is TRUE?

Accepted Answer

It ejects electrons from atoms to create ions, disrupting hydrogen bonding and oxidizing double covalent bonds

Question 8

Which equation best describes the constant percentage of microbial death rate per minute?

Accepted Answer

$$N_t = N_0$ 	imes e$$^{-kt}$$

Question 9

A food company wants to preserve fruit by inhibiting microbial growth. Which method is most effective?

Accepted Answer

Osmotic pressure using high concentrations of sugar

Question 10

Which of the following is a disadvantage of using gaseous agents for sterilization?

Accepted Answer

They can be hazardous to people

Question 11

Which chemical agent is NOT recommended for treating open wounds due to the presence of catalase in tissues?

Accepted Answer

Hydrogen peroxide

Question 12

Which of the following is a correct statement about the effect of temperature on antimicrobial chemicals?

Accepted Answer

Agents are more effective at warmer temperatures

Question 13

Which of the following is a mechanism by which alcohols control microbial growth?

Accepted Answer

Denaturation of proteins and disruption of cytoplasmic membranes

Question 14

A researcher wants to determine the minimum concentration of a disinfectant required to kill bacteria. Which test should they use?

Accepted Answer

Minimum bactericidal concentration test

Question 15

Which of the following is TRUE regarding nonenveloped viruses and their resistance to antimicrobial agents?

Accepted Answer

They are more resistant than most gram-positive bacteria

Question 16

Which of the following is a limitation of boiling as a method of microbial control?

Accepted Answer

Endospores, protozoan cysts, and some viruses can survive boiling

Question 17

Which of the following statements about desiccation and lyophilization is CORRECT?

Accepted Answer

Desiccation inhibits growth due to removal of water

Question 18

Which of the following is a reason why UV light is suitable for disinfecting air and transparent fluids but not for sterilizing thick materials?

Accepted Answer

UV light does not penetrate well

Question 19

Which of the following is a property of halogens as antimicrobial agents?

Accepted Answer

They denature proteins by oxidation or by denaturation

Question 20

A laboratory is handling a moderately hazardous agent. Which biosafety level should be used?

Accepted Answer

Biosafety Level 2

Microbial Control: Methods, Efficacy, and Mechanisms

Study Guide - Practice Questions