Chemical Control of Microbial Growth
MBIO 3400 Exam 2 fully solved
What are the definitions of disinfectants, antiseptics, and sanitizers? - correct answer ✔✔Antiseptic: A
microbicidal or micro biostatic agent that is intended for use on living tissue.
Disinfectant: A microbicidal agent that is intended for use on inanimate objects and surfaces.
Sanitizer: An agent that reduces microbial populations to safe levels that meet public health standards
(usually 99% killing).
What four classes of chemical agents disrupt cell membranes and denature proteins? - correct answer
✔✔Phenol, Phenolics (phenol derivatives), Alcohols, and Surfactants (soaps and detergents).
What is the phenol coefficient? - correct answer ✔✔Phenol coefficient of phenol = 1
Phenol coefficient >1: better disinfectant than phenol.
Phenol coefficient <1: worse disinfectant than phenol.
How do surfactants reduce surface tension? What is one large family of surfactants that has potent
antimicrobial activity? - correct answer ✔✔Surfactants reduce surface tension by decreasing the
attraction among molecules. A result of this reduction in surface tension is that the solvent became more
effective at dissolving solute molecules.
Detergents and soaps.
What four classes of chemical agents inactivate enzymes reacting with chemical groups essential for
activity? - correct answer ✔✔Peroxides, Halogens, Heavy metals, and Alkylating agents (gasses and
aldehydes).
What two classes of chemical agents kill or inhibit microbial growth by other mechanisms? - correct
answer ✔✔Dyes and Concentrated acids and bases.
MBIO 3400 Exam 2 fully solved
What are the definitions of disinfectants, antiseptics, and sanitizers? - correct answer ✔✔Antiseptic: A
microbicidal or micro biostatic agent that is intended for use on living tissue.
Disinfectant: A microbicidal agent that is intended for use on inanimate objects and surfaces.
Sanitizer: An agent that reduces microbial populations to safe levels that meet public health standards
(usually 99% killing).
What four classes of chemical agents disrupt cell membranes and denature proteins? - correct answer
✔✔Phenol, Phenolics (phenol derivatives), Alcohols, and Surfactants (soaps and detergents).
What is the phenol coefficient? - correct answer ✔✔Phenol coefficient of phenol = 1
Phenol coefficient >1: better disinfectant than phenol.
Phenol coefficient <1: worse disinfectant than phenol.
How do surfactants reduce surface tension? What is one large family of surfactants that has potent
antimicrobial activity? - correct answer ✔✔Surfactants reduce surface tension by decreasing the
attraction among molecules. A result of this reduction in surface tension is that the solvent became more
effective at dissolving solute molecules.
Detergents and soaps.
What four classes of chemical agents inactivate enzymes reacting with chemical groups essential for
activity? - correct answer ✔✔Peroxides, Halogens, Heavy metals, and Alkylating agents (gasses and
aldehydes).
What two classes of chemical agents kill or inhibit microbial growth by other mechanisms? - correct
answer ✔✔Dyes and Concentrated acids and bases.
