Question 1

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

Accepted Answer

Sterilization removes all microbial life, while disinfection only destroys harmful microorganisms.

Question 2

A hospital technician needs to sterilize a heat-sensitive solution. Which method is most appropriate?

Accepted Answer

Filtration using a membrane filter with pore size $$0.22\ \mu m$$

Question 3

Which of the following statements about the microbial death curve is correct?

Accepted Answer

The death rate is constant, and for each minute of treatment, 90% of the population is killed.

Question 4

A laboratory is testing the effectiveness of 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 where bacteria do not grow

Question 5

Which of the following is the correct definition of decimal reduction time (D value)?

Accepted Answer

The time in minutes to kill 90% of a specific population of bacteria at a given temperature

Question 6

Which physical method of microbial control is most effective for sterilizing large volumes of culture media in a laboratory?

Accepted Answer

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

Question 7

Which of the following chemical agents is most effective against both endospores and mycobacteria?

Accepted Answer

Glutaraldehyde

Question 8

Why are HEPA filters used in hospital operating rooms and biological safety cabinets?

Accepted Answer

They remove microbes larger than $$0.3\ \mu m in $$diameter from the air.

Question 9

Which of the following best explains why moist heat is generally more effective than dry heat for sterilization?

Accepted Answer

Moist heat coagulates and denatures proteins more efficiently.

Question 10

A food processing plant uses high concentrations of salt to preserve meat. What is the primary mechanism by which this method controls microbial growth?

Accepted Answer

Osmotic pressure causes plasmolysis in microbial cells.

Question 11

Which of the following statements about alcohols as disinfectants is true?

Accepted Answer

Alcohols require water to be effective and do not kill endospores.

Question 12

A researcher is using a use-dilution test to evaluate a new disinfectant. What is the main purpose of this test?

Accepted Answer

To determine whether bacteria survive treatment with the disinfectant

Question 13

Which of the following is a limitation of using ultraviolet (UV) radiation for sterilization?

Accepted Answer

UV radiation does not penetrate surfaces well.

Question 14

Which of the following is the primary action of phenolic compounds as disinfectants?

Accepted Answer

Injury to plasma membrane lipids, causing leakage

Question 15

A nurse is preparing a surgical site using an antiseptic. Which of the following best describes the purpose of this procedure?

Accepted Answer

To destroy harmful microorganisms from living tissue

Question 16

Which of the following statements about glutaraldehyde is correct?

Accepted Answer

It is one of the few liquid chemical sterilizing agents.

Question 17

Which of the following is a real-world example of degerming?

Accepted Answer

Swabbing skin with alcohol before an injection

Question 18

Which of the following best explains why large containers require longer sterilization times in an autoclave?

Accepted Answer

It takes longer for steam to penetrate and heat the entire volume.

Question 19

Which of the following is the main reason why organic matter can interfere with the effectiveness of disinfectants?

Accepted Answer

Organic matter can react with and inactivate disinfectants.

Question 20

A dairy plant uses pasteurization to treat milk. Which of the following best describes the process?

Accepted Answer

Heating milk to $$72^\circ C$$ for 15 seconds to reduce spoilage organisms and pathogens

Chapter 7 - The Control of Microbial Growth – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards