Question 1

Which of the following chemical agents is most appropriate for disinfecting heat-sensitive hospital mattresses, and what is its primary mode of action?

Accepted Answer

Ethylene oxide gas; damages proteins and nucleic acids

Question 2

A patient is about to undergo surgery. Which chemical agent is most commonly used to disinfect the skin at the surgical site, and what is its mechanism?

Accepted Answer

Betadine (iodine); damages proteins

Question 3

Why are Gram-negative bacteria generally more resistant to chemical disinfectants than Gram-positive bacteria?

Accepted Answer

They possess an outer membrane that restricts entry of chemicals

Question 4

Which of the following best explains why 100% ethanol is less effective as an antimicrobial agent than 70% ethanol?

Accepted Answer

Water is required to denature proteins, so 70% ethanol is more effective

Question 5

Which of the following lists the order of microbial resistance to chemical agents from most to least resistant?

Accepted Answer

Prions \u003e bacterial endospores \u003e Gram-negative bacteria \u003e Gram-positive bacteria

Question 6

A hospital needs to sterilize reusable surgical instruments. Which chemical method is most suitable, and what is its main target?

Accepted Answer

Glutaraldehyde; damages proteins and nucleic acids

Question 7

Which of the following statements about phenolics is correct?

Accepted Answer

They damage proteins and membranes

Question 8

A laboratory technician is preparing a disinfectant solution for cleaning surfaces contaminated with blood. Which chemical is most appropriate and why?

Accepted Answer

Bleach; it damages proteins

Question 9

Which chemical agent is commonly used for embalming and what is its primary mode of action?

Accepted Answer

Glutaraldehyde; damages proteins and nucleic acids

Question 10

A swimming pool is treated to prevent microbial growth. Which chemical is most likely used and what is its mechanism?

Accepted Answer

Chlorine; damages proteins

Question 11

Which of the following best describes why prions are the most resistant to chemical disinfectants?

Accepted Answer

They are misfolded proteins that resist denaturation

Question 12

A nurse uses Purell hand sanitizer (62-65% ethanol) before patient contact. Why is this concentration effective?

Accepted Answer

It contains enough water to denature proteins

Question 13

Which of the following is a correct application of halogens in microbial control?

Accepted Answer

Iodine for skin and wound treatment

Question 14

A researcher needs to sterilize a solution that cannot be heated. Which chemical method is most appropriate?

Accepted Answer

Ethylene oxide gas

Question 15

Which of the following best explains why bacterial endospores are more resistant to chemical disinfectants than vegetative cells?

Accepted Answer

Endospores have a tough protein coat and low metabolic activity

Question 16

Which chemical agent is found in antibacterial soap and what is its primary target?

Accepted Answer

Triclosan; damages proteins and membranes

Question 17

A water treatment plant uses a chemical to disinfect wastewater. Which chemical is most likely used and what is its mechanism?

Accepted Answer

Chlorine; damages proteins

Question 18

Which of the following is a limitation of using alcohols as disinfectants?

Accepted Answer

They require water to be effective

Question 19

A laboratory is testing the effectiveness of various ethanol concentrations against Streptococcus pyogenes. Which concentration is most effective and why?

Accepted Answer

70% ethanol; water is required for protein denaturation

Question 20

Which of the following best describes the use of glutaraldehyde in a hospital setting?

Accepted Answer

Disinfecting medical equipment by damaging proteins and nucleic acids

Chemical Methods of Controlling Microbial Growth in the Environment

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