MCB 100 Exam 4 Study Guide UPDATED ACTUAL Questions And Correct
Answers
C
Terms in this set (224)
Biosafety level 1 (BSL-1) Handling pathogens that do not cause disease in healthy humans
Biosafety level 2 (BSL-2) Handling moderately biohazardous agents (that could cause harm) in biosafety
cabinets
Using personal protective equipment
Biosafety level 3 (BSL-3) Handling highly pathogenic, infectious, or toxic microbes in biosafety cabinets
using PPE
Using special facility with high-efficiency particulate air (HEPA) filters
Biosafety level 4 (BSL-4) Handling highly infectious pathogens that cause deadly disease (for which there
are no treatments) require special lab facilities
natural agents used to kill or slow down the growth of antibiotics, natural acids such as vinegar or citrus juice, alcohols
microbes
artificial agents used to kill or slow down the growth of chemicals, drugs, detergents
microbes
used externally on inanimate objects disinfectants, sanitizers
used on body surfaces antiseptics, germicides
safe to ingest or inject antibiotics, antimicrobials
sterilization Removal of all forms of life (microbial) from a surface or substance (object or
fluid) achieved by treatment with heat, chemicals, irradiation, high pressure, or
filtration
Object is considered sterile or aseptic after sterilization
Sterilization is distinct from disinfection, sanitization, and pasteurization, which are
methods used to reduce the microbial load but do not eliminate all forms of life
present
antimicrobials Substances that kill or inhibit the growth of microbes, such as bacteria, fungi, or
parasites
Drugs that act against viruses are antivirals
antimicrobials - microbicidal (germicidal) kill the microbe
lyse and kill bacteria
, antimicrobials - microbiostatic prevent the growth of the microbe
stop or slow down bacterial growth, but the bacteria are not killed
microbial death permanent loss of reproductive ability of a microbe under ideal environmental
conditions
microbial death rate often a constant rate for any given microbe under a particular set of conditions
Physical sterilization - filtration Used for heat-sensitive solutions that cannot be heat-sterilized, such as certain
medicines, vitamins, amino acids, cosmetics, and cold-filtered beer
Physical methods of microbial control - Heating inactivates or kills all kinds of microbes, including bacterial spores and viruses,
depending on the method used
pasteurization food is heated for a specific length of time at a specific temperature and then
immediately cooled. All of the microbes are not killed; their numbers are just
reduced. The intent is to reduce spoilage due to reduced microbial growth
Dry heating or baking involves conduction- heating the exterior surface of an item to eventually heat the
entire item to the desired temperature. Dry heat removes moisture and oxidizes
proteins and lipids.
boiling moist-free sterilization process involves heating at boiling temperatures. Boiling
for 20 min will kill all vegetative bacterial cells, but not always spores.
Tyndallization uses 3 consecutive steam treatments over the course of 3 days to
achieve sterilization
Physical sterilization - autoclaving Heating: pressure cooking - autoclaving (steam heat under pressure)
Requires aseptic technique
Pressure-heat denatures microbial proteins and often lysis cells
Physical sterilization - UV irradiation UV light can be used to kill microbes on surfaces
UV light damages DNA by formation of pyrimidine dimers
DNA repair mechanisms can remove dimers, but one of the repair systems tends
to introduce errors that can lead to increasing the frequency of mutations
Physical sterilization - ionizing irradiation Can eliminate disease causing microbes from foods or other material by treating
the items with approved levels of ionizing (high energy) radiation
Also called cold pasteurization or cold sterilization
Used for medical devices, cosmetics, feminine hygiene and infant consumables
Kills by damaging DNA so that the microbe cannot replicate
Parasites and insects are rapidly killed, bacteria and bacterial spores are easily
killed, but irradiation is less effective against viruses, and not at all effective
against proteins
Irradiated food generally has a longer shelf-life and does not spoil as readily
Extensive, longitudinal feeding studies have revealed no ill effects on animals or
humans
Radioactive gamma rays High energy photons from radioactive material are capable of high penetration
Used extensively to sterilize medical, dental, and household products and
products used for cancer treatment or other immune compromised situations
Answers
C
Terms in this set (224)
Biosafety level 1 (BSL-1) Handling pathogens that do not cause disease in healthy humans
Biosafety level 2 (BSL-2) Handling moderately biohazardous agents (that could cause harm) in biosafety
cabinets
Using personal protective equipment
Biosafety level 3 (BSL-3) Handling highly pathogenic, infectious, or toxic microbes in biosafety cabinets
using PPE
Using special facility with high-efficiency particulate air (HEPA) filters
Biosafety level 4 (BSL-4) Handling highly infectious pathogens that cause deadly disease (for which there
are no treatments) require special lab facilities
natural agents used to kill or slow down the growth of antibiotics, natural acids such as vinegar or citrus juice, alcohols
microbes
artificial agents used to kill or slow down the growth of chemicals, drugs, detergents
microbes
used externally on inanimate objects disinfectants, sanitizers
used on body surfaces antiseptics, germicides
safe to ingest or inject antibiotics, antimicrobials
sterilization Removal of all forms of life (microbial) from a surface or substance (object or
fluid) achieved by treatment with heat, chemicals, irradiation, high pressure, or
filtration
Object is considered sterile or aseptic after sterilization
Sterilization is distinct from disinfection, sanitization, and pasteurization, which are
methods used to reduce the microbial load but do not eliminate all forms of life
present
antimicrobials Substances that kill or inhibit the growth of microbes, such as bacteria, fungi, or
parasites
Drugs that act against viruses are antivirals
antimicrobials - microbicidal (germicidal) kill the microbe
lyse and kill bacteria
, antimicrobials - microbiostatic prevent the growth of the microbe
stop or slow down bacterial growth, but the bacteria are not killed
microbial death permanent loss of reproductive ability of a microbe under ideal environmental
conditions
microbial death rate often a constant rate for any given microbe under a particular set of conditions
Physical sterilization - filtration Used for heat-sensitive solutions that cannot be heat-sterilized, such as certain
medicines, vitamins, amino acids, cosmetics, and cold-filtered beer
Physical methods of microbial control - Heating inactivates or kills all kinds of microbes, including bacterial spores and viruses,
depending on the method used
pasteurization food is heated for a specific length of time at a specific temperature and then
immediately cooled. All of the microbes are not killed; their numbers are just
reduced. The intent is to reduce spoilage due to reduced microbial growth
Dry heating or baking involves conduction- heating the exterior surface of an item to eventually heat the
entire item to the desired temperature. Dry heat removes moisture and oxidizes
proteins and lipids.
boiling moist-free sterilization process involves heating at boiling temperatures. Boiling
for 20 min will kill all vegetative bacterial cells, but not always spores.
Tyndallization uses 3 consecutive steam treatments over the course of 3 days to
achieve sterilization
Physical sterilization - autoclaving Heating: pressure cooking - autoclaving (steam heat under pressure)
Requires aseptic technique
Pressure-heat denatures microbial proteins and often lysis cells
Physical sterilization - UV irradiation UV light can be used to kill microbes on surfaces
UV light damages DNA by formation of pyrimidine dimers
DNA repair mechanisms can remove dimers, but one of the repair systems tends
to introduce errors that can lead to increasing the frequency of mutations
Physical sterilization - ionizing irradiation Can eliminate disease causing microbes from foods or other material by treating
the items with approved levels of ionizing (high energy) radiation
Also called cold pasteurization or cold sterilization
Used for medical devices, cosmetics, feminine hygiene and infant consumables
Kills by damaging DNA so that the microbe cannot replicate
Parasites and insects are rapidly killed, bacteria and bacterial spores are easily
killed, but irradiation is less effective against viruses, and not at all effective
against proteins
Irradiated food generally has a longer shelf-life and does not spoil as readily
Extensive, longitudinal feeding studies have revealed no ill effects on animals or
humans
Radioactive gamma rays High energy photons from radioactive material are capable of high penetration
Used extensively to sterilize medical, dental, and household products and
products used for cancer treatment or other immune compromised situations
