Question 1

Which of the following best describes the process of sterilization?

Accepted Answer

The destruction or removal of all microbes, including viruses and endospores, but not prions, from an object.

Question 2

A surgeon is preparing to insert a catheter into a patient. Which level of germicide is required to sterilize the catheter before use?

Accepted Answer

High-level germicide

Question 3

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that require heating to 482 $$^\circC $$for 4 hours to denature.

Question 4

Which of the following best explains why objects must be cleaned of organic material before sterilization or disinfection?

Accepted Answer

Organic materials can react with and inactivate disinfectants, reducing their effectiveness.

Question 5

A hospital is disinfecting surgical instruments that will only contact mucous membranes. Which level of germicide should be used?

Accepted Answer

Intermediate-level germicide

Question 6

Which of the following is the most resilient form of life to control methods, requiring the harshest conditions for destruction?

Accepted Answer

Endospores of Bacillus and Clostridium

Question 7

A laboratory is working with Ebola virus. Which biosafety level (BSL) is required for this work?

Accepted Answer

BSL-4

Question 8

Which of the following statements about boiling as a method of microbial control is correct?

Accepted Answer

Boiling kills vegetative cells of bacteria and fungi, most viruses, and protozoan trophozoites in 10 minutes at sea level.

Question 9

Which of the following best describes the process of lyophilization?

Accepted Answer

Instantly freezing a culture in liquid nitrogen or dry ice, then removing water by vacuum sublimation.

Question 10

A pharmaceutical company needs to sterilize a heat-sensitive antibiotic solution. Which method is most appropriate?

Accepted Answer

Filtration through a nitrocellulose or plastic membrane

Question 11

Which of the following chemical elements is NOT one of the four very reactive, nonmetallic elements used in microbial control?

Accepted Answer

Sodium

Question 12

Which of the following statements about the use of electron beams in sterilization is correct?

Accepted Answer

Electron beams are produced by cathode ray machines and are used to sterilize spices, meats, and medical supplies.

Question 13

Which of the following best explains why Mycobacterium species are difficult to disinfect?

Accepted Answer

Their cell walls contain large amounts of waxy lipid, making them resistant to many disinfectants.

Question 14

Which of the following is a correct statement about the effect of refrigeration on microbial growth?

Accepted Answer

Refrigeration at 0 $$^\circC to 7$$ $$^\circC $$slows microbial metabolism and growth.

Question 15

Which of the following best describes the action of halogens in microbial control?

Accepted Answer

They denature proteins by disrupting hydrogen and disulfide bonds.

Question 16

A solution is labeled as 'bacteriostatic.' What does this mean?

Accepted Answer

It inhibits bacterial metabolism and growth without necessarily killing them.

Question 17

Which of the following is a correct example of degerming?

Accepted Answer

Washing hands with soap and water, physically removing microbes.

Question 18

Which of the following best describes the effect of pyrimidine dimers on DNA?

Accepted Answer

They disrupt hydrogen bonds between complementary DNA strands and distort the DNA shape.

Question 19

Which of the following metals is used in microbial control but is toxic at low concentrations?

Accepted Answer

Silver

Question 20

Which of the following gases is used for sterilization of heat-sensitive medical equipment?

Accepted Answer

Ethylene oxide

Controlling Microbial Growth in the Environment: Key Concepts and Methods

Study Guide - Practice Questions