Q: Which equation best represents the exponential death rate of bacteria when treated with an antimicrobial agent?

$$N_t = N_0$ \times 10$$^{-kt}$$

Q: Which equation describes the thermal death point (TDP) for a microbial population?

$$TDP = \text{lowest temperature at which all cells are killed in 10 min}$$

Question 1

Which term describes the process of removing and destroying all microbial life, including endospores, from an object?

Accepted Answer

Sterilization

Question 2

A hospital uses an autoclave to sterilize surgical instruments. If the autoclave operates at 121°C and 15 psi for 15 minutes, what is the primary mechanism by which microbial life is destroyed?

Accepted Answer

Coagulation and denaturation of proteins

Question 3

Which of the following is TRUE regarding the decimal reduction time (DRT) in microbial control?

Accepted Answer

DRT is the time required to kill 90% of a microbial population at a specific temperature

Question 4

A chemical agent that inhibits, but does not kill, bacterial growth is best described as:

Accepted Answer

Bacteriostasis

Question 5

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

Accepted Answer

Filtration

Question 6

Why are gram-negative bacteria generally more resistant to chemical biocides than gram-positive bacteria?

Accepted Answer

Gram-negative bacteria possess an outer membrane that restricts entry of biocides

Question 7

Which chemical disinfectant is considered a sporicide and can be used to sterilize heat-sensitive medical equipment?

Accepted Answer

Glutaraldehyde

Question 8

A nurse uses an alcohol swab before giving an injection. This process is best described as:

Accepted Answer

Degerming

Question 9

Which equation best represents the exponential death rate of bacteria when treated with an antimicrobial agent?

Accepted Answer

$$N_t = N_0$ 	imes 10$$^{-kt}$$

Question 10

Pasteurization is used to reduce spoilage organisms and pathogens in milk. Which of the following describes the high-temperature short-time (HTST) method?

Accepted Answer

72°C for 15 seconds

Question 11

Which of the following statements about autoclave sterilization is CORRECT?

Accepted Answer

Sterilization time increases with larger container volumes

Question 12

Which chemical agent is used to prevent ophthalmia neonatorum in newborns?

Accepted Answer

Silver nitrate

Question 13

Which physical method of microbial control works by creating a hypertonic environment, causing plasmolysis in bacteria?

Accepted Answer

Osmotic pressure

Question 14

Ionizing radiation kills cells primarily by:

Accepted Answer

Damaging DNA by causing lethal mutations

Question 15

Which chemical disinfectant is most effective in the presence of organic matter and persists for long periods?

Accepted Answer

Phenol

Question 16

A dairy industry is interested in using surface-active agents for cleaning. Which characteristic makes these agents attractive for this purpose?

Accepted Answer

They emulsify fats and oils, aiding in degerming

Question 17

Which of the following is NOT a preferred use for quaternary ammonium compounds (quats)?

Accepted Answer

Sterilizing surgical instruments

Question 18

Which equation describes the thermal death point (TDP) for a microbial population?

Accepted Answer

$$TDP = 	ext{lowest temperature at which all cells are killed in 10 min}$$

Question 19

Which chemical method is used for sterilizing heat-sensitive medical implants and operates above the critical temperature and pressure?

Accepted Answer

Supercritical CO$$_2$$

Question 20

A zone of inhibition is observed around a disk in the disk-diffusion method. What does this indicate?

Accepted Answer

The chemical agent inhibits microbial growth

Chapter 7: The Control of Microbial Growth – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards