BIO 210 (MICROBIOLOGY) EXAM 4
QUESTIONS AND ANSWERS 100%
CORRECT.
Sterilization - ANSWERDestruction of all life (bacteria, viruses, and spores). Used on
inanimate objects.
Common method: autoclave
Disinfectant - ANSWERReduces the microbial numbers on inanimate object (things we
do not want on our skin).
Ex: UV light, boiling, cleaning products (bleach).
Antiseptics - ANSWERAlso called De-germation
Reduces the microbial numbers on living tissue
Ex: Alcohol, Germ X, Iodine, soap, etc.
Sanitization - ANSWERAlso known as decontamination.
Lowers microbial count to safe levels by not completely to zero like sterilization.
Common Method: dishwashers, chemical disinfectants, air sanitization with UV light.
Suffix -cide - ANSWERmeans to kill
Suffix -static - ANSWERmeans to stop or stand still
4 targets of physical and chemical agents - ANSWERcell wall
cell membrane
DNA or RNA
Proteins (enzymes)
Chemical agent target: cell wall - ANSWERchemical reagent that damages this
component of the cell can do it by:
blocking the synthesis of it, digesting it, or breaking down its surface
ex: detergents and alcohols
,Chemical agent target: cell membrane - ANSWERthis is where most of the ATP
production occurs and allows molecules to move in or out of the cell
Without this component to the cell, microbes cannot perform basic pathways without
ATP being replenished
ex: surfactants (hand soap) and detergents.
Chemical agent target: DNA or RNA - ANSWERSome microbial control agents being to
this to prevent transcription and/or translation. Others just directly damage this
component.
ex: Gamma, X-rays, and UV radiation
Some microbial control agents cause mutations in this
ex: formaldehydes and ethylene oxide
Chemical agent target: protein (enzyme) - ANSWERAntimicrobials that control this can
denature this by breaking the hydrogen bonds in the folding causing irreversible
damage.
ex: heat, heavy metals, alcohols, and acids
Why does heat kill microbe - ANSWERheat denatures proteins which means that the
basic pathways within the cell cannot be performed.
Thermal death time (TDT) - ANSWERthe time it takes to kill microbes at a certain
temperature
ex: E. coli dies in 20 minutes at 55 oC
Thermal death point (TDP) - ANSWERthe lowest temperature at which a microbe is
killed in 10 minutes
ex: E. coli dies at 80 oC within 10 minutes.
Moist heat - ANSWERthis kills by applying heat at high moisture.
ex: boiling, autoclaving, and pasteurization
Autoclaving - ANSWERmachine that applies steam, heat, and pressure to sterilize
Done at 121 oC for 20 minutes at 15 psi.
, Pasteurization - ANSWERmoderate heat is applied which reduces populations of
microbes
ex: milk, cheese, and orange juice
Dry heat - ANSWERheat with low moisture
Mode of action: denatures proteins
Ex: flaming the looping incineration (anything with fire)
Cold temperatures - ANSWERslows down the growth of microbes but does not kill
them.
method of action: slows down enzyme activity.
ex: fridge or freezer
Ionizing radiation - ANSWERcauses ions to form. highly effective alternative for
sterilizing materials that are sensitive to heat and cold.
method of action: damages DNA (mutations) and proteins.
ex: Gamma and X-rays
Nonionizing radiation - ANSWERexcites electrons which causes abnormal bonds.
method of action: damages DNA = Thymine dimers
ex: usage of UV light on work surfaces and water.
Halogens - ANSWERIodine (antiseptic) and Chlorine (disinfectant)
Method of action: proteins and DNA/RNA
Kill microbes and endospores
Phenols - ANSWERCarbolic acid
Method of action: proteins and cell membranes
Can kills some bacteria, viruses, and fungi
Uses: personal hygiene, mouthwashes, and soaps
QUESTIONS AND ANSWERS 100%
CORRECT.
Sterilization - ANSWERDestruction of all life (bacteria, viruses, and spores). Used on
inanimate objects.
Common method: autoclave
Disinfectant - ANSWERReduces the microbial numbers on inanimate object (things we
do not want on our skin).
Ex: UV light, boiling, cleaning products (bleach).
Antiseptics - ANSWERAlso called De-germation
Reduces the microbial numbers on living tissue
Ex: Alcohol, Germ X, Iodine, soap, etc.
Sanitization - ANSWERAlso known as decontamination.
Lowers microbial count to safe levels by not completely to zero like sterilization.
Common Method: dishwashers, chemical disinfectants, air sanitization with UV light.
Suffix -cide - ANSWERmeans to kill
Suffix -static - ANSWERmeans to stop or stand still
4 targets of physical and chemical agents - ANSWERcell wall
cell membrane
DNA or RNA
Proteins (enzymes)
Chemical agent target: cell wall - ANSWERchemical reagent that damages this
component of the cell can do it by:
blocking the synthesis of it, digesting it, or breaking down its surface
ex: detergents and alcohols
,Chemical agent target: cell membrane - ANSWERthis is where most of the ATP
production occurs and allows molecules to move in or out of the cell
Without this component to the cell, microbes cannot perform basic pathways without
ATP being replenished
ex: surfactants (hand soap) and detergents.
Chemical agent target: DNA or RNA - ANSWERSome microbial control agents being to
this to prevent transcription and/or translation. Others just directly damage this
component.
ex: Gamma, X-rays, and UV radiation
Some microbial control agents cause mutations in this
ex: formaldehydes and ethylene oxide
Chemical agent target: protein (enzyme) - ANSWERAntimicrobials that control this can
denature this by breaking the hydrogen bonds in the folding causing irreversible
damage.
ex: heat, heavy metals, alcohols, and acids
Why does heat kill microbe - ANSWERheat denatures proteins which means that the
basic pathways within the cell cannot be performed.
Thermal death time (TDT) - ANSWERthe time it takes to kill microbes at a certain
temperature
ex: E. coli dies in 20 minutes at 55 oC
Thermal death point (TDP) - ANSWERthe lowest temperature at which a microbe is
killed in 10 minutes
ex: E. coli dies at 80 oC within 10 minutes.
Moist heat - ANSWERthis kills by applying heat at high moisture.
ex: boiling, autoclaving, and pasteurization
Autoclaving - ANSWERmachine that applies steam, heat, and pressure to sterilize
Done at 121 oC for 20 minutes at 15 psi.
, Pasteurization - ANSWERmoderate heat is applied which reduces populations of
microbes
ex: milk, cheese, and orange juice
Dry heat - ANSWERheat with low moisture
Mode of action: denatures proteins
Ex: flaming the looping incineration (anything with fire)
Cold temperatures - ANSWERslows down the growth of microbes but does not kill
them.
method of action: slows down enzyme activity.
ex: fridge or freezer
Ionizing radiation - ANSWERcauses ions to form. highly effective alternative for
sterilizing materials that are sensitive to heat and cold.
method of action: damages DNA (mutations) and proteins.
ex: Gamma and X-rays
Nonionizing radiation - ANSWERexcites electrons which causes abnormal bonds.
method of action: damages DNA = Thymine dimers
ex: usage of UV light on work surfaces and water.
Halogens - ANSWERIodine (antiseptic) and Chlorine (disinfectant)
Method of action: proteins and DNA/RNA
Kill microbes and endospores
Phenols - ANSWERCarbolic acid
Method of action: proteins and cell membranes
Can kills some bacteria, viruses, and fungi
Uses: personal hygiene, mouthwashes, and soaps
