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terminology & self quiz questions


chemical agent used on inanimate objectsj (surface) to destroy microorganisms. Ex: alcohol


chemical agent that can be safely used externally on tissues to destroy microorganisms or inhibit their growth. Ex: alcohol

time, temp, pH, concentration

the potency of chemical antimicrobial agents are affected by these


30 seconds to one minute


heat speads up reaction; cold slows down. Ex: warm tissue


environmental facter in the potency of chemical agents


full strength can be toxic. 5-10 % is just as good as full strength because full strength can be toxic

phenol coefficient

the ratio of a dilution of an agent to the dilution of phenol that will kill all organisms in 10 minutes but not in 5 minutes

filter paper method

methods of evaluation the antimicrobial properties of a chemical agent using filter paper disks placed on an inoculated agar plate

use dilution method


ideal disinfectant should be...

fast acting, effective, penetrate ealily, easy to prepare, inexpensive, pleasant odor or none at all

reactions that affect proteins

denaturation, heat, acids, alkalis and other agents

reactions that affect membranes

surfactants, wetting agents

reactions that affect other cell components

alkylating agents

reactions that affect viruses

alkylating agents, detergents, alcohols, dyes

specific chemical antimicrobial agents

soaps/detergents, acids/alkalis, heavy metals, halogens, alcohols, phenols, oxidizing agents, alkylating agents, dyes, other agents


cloud of tiny liquid droplets suspended in air


an insturment used for sterilization by means of moist heat under pressure


referring to an agent that inhibits the growth of bacteria


the formation of a cavity inside the cytoplasm of a cell

decimal reduction time (DRT)

the length of time needed to kill 90% of the organisms in a given population at a specified temperature


reducing the number of pathogenic organisms on objects or in materials so that they pose no threat of disease


method of sterilization that uses a mebrane filter to separate bacteria from growth media


freeze drying, a means of preservation of cultures


mild heating to destroy pathogens and other organisms that cause spoilage

phenol coefficient

a numerial expression for the effectiveness of a disinfectant relative to that of phenol


shrinking of a cell; losing water

quaternary ammonium compound (quat)

a cationic detergent that has four organic groups attached to a nitrogen atom


a unit of radiation energy absorbed per gram of tissue


disruption of cells by sound waves


the state in which there are no living organisms in or on a material


the killing or removal of ALL microorganisms in any material or on any object (surgical instruments)


a substance that reduces surface tension

thermal death point

the temperature that kills all the bacteria in a 24-hour-old broth culture at neutral pH in 10 minutes

thermal death time

the time required to kill all the bacteria in a particular culture at a specified temperature


an alcoholic solution

ultrahigh temp (UHT) processing

a method of sterililzation milk and daury products by raising the temperature to 87.8 degrees C for 3 seconds

use-dilution test

a method of evaluation the antimicrobial properties of a chemical agent using standard preparation of certain test bacteria

wetting agent

a detergent solution often used with other chmical agents to penetrate fatty substances


kills microbes


inactivates viruses


kills bacterial endospores and fungal spores


kills yeasts and molds


kills bacteria


reduction in numbers of pathogenic organisms on objects or in materials so that they do not pose a disease threat

pasteurization process

kills microbial pathogens that might be present in milk


active antimicrobial ingredient in bleach

gaseous ethylene oxide

method of sterilizing rubber, plastic and bulky materials (mattresses)

15 minutes

minimum time used for sterilization by autoclaving

bacillus stearothermophilus

recommended method for testing that an autoclave has truly sterilized a load uses this


microwaves will only heat materials that contain this

passing liquid through a 0.22-┬Ám filter

method that kills bacteria in a liquid without damaging heat-labile proteins in the solution

heat-sensitive materials

the use of autoclaves is limited with these


the percentage of alcohol that is the most effective

soaps & detergents

these aid in the removal of microbes, oils, and dirt but does not sterilize


commonly used as food preservatives


in soap and helps destroy microorganisms

silver nitrate

used to kill gonococci (among the agents containing heavy metals)

mercury-containing compounds

used to disinfect instruments and skin (among the agents containing heavy metals)


used to kill pathogens in water (among the agents containing halogens)


major ingredient in several skin disinfectants (among the agents containing halogens)

phenol derivatives

can be used on skin, instruments, dises and furniture and to destroy discarded cultures

oxidizing agents

useful in disinfecting puncture wounds

alkylating agents

can be used to disinfect or to sterilize a variety of materials, but all are carcinogens


includes UV light, ionizing radiaion, and sometimes microwaves and strong sunlight


disruption of cells by sound waves

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