BIO 175 Exam 2 Study Guide (Chapter 9)
Questions with Correct Answers
•How does it kill or inhibit the microorganism?
-The duration of exposure of microbes to the agent (contact time)
•Most agents are more effective with longer contact times
-Condsiderations:
-Number of microbes
-Type of microbes targeted
-The presence of solvents, organics, inhibitors
-Temperature and pH of the environment can also affect antimicrobial effectiveness
Describe the possible results of heat and chemical treatment of cell proteins in terms of changing
protein shape and protein function
Identify cellular targets of microbial control, provide example agents for each target and describe
the effects of these agents
, Summarize the function, mode of action, common uses and limitations of chlorine, iodine,
hydrogen peroxide, ethylene oxide, phenolics, chlorhexidine, alcohol, metal compounds and
detergents/surfactants as chemical agents of microbial control
Differentiate moist and dry heat in terms of efficacy, microbicidal effects, and common methods
of both used in microbial control -Elevated temperatures are microbicidal
-Lower temperatures are microbistatic
-Moist heat: hot water, boiling water, or steam between 60°C and 135°C
-Operates at lower temperatures and shorter exposure times to achieve the same effectiveness as
dry heat
-Ex. Steam under pressure (autoclaving), boiling water, pasteurization
-Dry heat: hot air or an open flame, which ranges from 160°C to several thousand degrees C
-Dehydrates the cell
-Ex. Incineration, hot air oven
Questions with Correct Answers
•How does it kill or inhibit the microorganism?
-The duration of exposure of microbes to the agent (contact time)
•Most agents are more effective with longer contact times
-Condsiderations:
-Number of microbes
-Type of microbes targeted
-The presence of solvents, organics, inhibitors
-Temperature and pH of the environment can also affect antimicrobial effectiveness
Describe the possible results of heat and chemical treatment of cell proteins in terms of changing
protein shape and protein function
Identify cellular targets of microbial control, provide example agents for each target and describe
the effects of these agents
, Summarize the function, mode of action, common uses and limitations of chlorine, iodine,
hydrogen peroxide, ethylene oxide, phenolics, chlorhexidine, alcohol, metal compounds and
detergents/surfactants as chemical agents of microbial control
Differentiate moist and dry heat in terms of efficacy, microbicidal effects, and common methods
of both used in microbial control -Elevated temperatures are microbicidal
-Lower temperatures are microbistatic
-Moist heat: hot water, boiling water, or steam between 60°C and 135°C
-Operates at lower temperatures and shorter exposure times to achieve the same effectiveness as
dry heat
-Ex. Steam under pressure (autoclaving), boiling water, pasteurization
-Dry heat: hot air or an open flame, which ranges from 160°C to several thousand degrees C
-Dehydrates the cell
-Ex. Incineration, hot air oven
