MCB 100 Final Exam Questions and Correct
Answers
What are the four biosafety laboratory containment levels?
BSL-1, BSL-2, BSL-3, and BSL-4.
What does BSL stand for?
Biosafety Level.
What determines the biosafety level needed for a microbe?
Risk of containment failure, severity of infection, origin of microbe, host specificity, route of
exposure, transmissibility, and type of lab work.
What type of organisms are handled in BSL-1 labs?
Microbes that do not usually cause disease in healthy humans.
Give examples of BSL-1 microbes.
Lab-adapted nonpathogenic E. coli, Lactobacillus acidophilus, and Bacillus thuringiensis.
What are standard BSL-1 practices?
Handwashing, disinfecting surfaces, no eating/drinking/cosmetics, and routine
decontamination of work areas.
What type of organisms are handled in BSL-2 labs?
Moderately biohazardous agents that can cause harm.
Give examples of BSL-2 microbes.
,Bordetella pertussis, pathogenic E. coli, Salmonella, and Staphylococcus.
What safety practices are used in BSL-2 labs?
PPE, biosafety cabinets, limited access, sharps precautions, and trained personnel only.
What type of organisms are handled in BSL-3 labs?
Highly pathogenic, infectious, or toxic microbes that can cause serious disease but often have
treatments.
Give examples of BSL-3 microbes.
Bacillus anthracis, SARS-CoV-2, Mycobacterium tuberculosis, influenza virus, and Yersinia
pestis.
What facility features are important in BSL-3 labs?
HEPA-filtered exhaust air, double-door entry, biosafety cabinets, PPE, and negative air
pressure.
Why does a BSL-3 lab use negative pressure?
So air flows into the lab when doors open instead of allowing pathogens to escape outward.
What type of organisms are handled in BSL-4 labs?
Highly infectious pathogens that cause deadly disease and usually lack effective treatments.
Give examples of BSL-4 pathogens.
Ebola virus, Marburg virus, Lassa virus, and engineered 1918 influenza.
What safety features are used in BSL-4 labs?
Isolated facilities, special air handling, sealed airlocks, decontamination showers, UV rooms,
and positive-pressure suits with HEPA-filtered air.
, What is sterilization?
Complete removal or destruction of all forms of microbial life from an object, surface, or
fluid.
Is sterilization the same as disinfection?
No. Sterilization removes all microbial life, while disinfection reduces microbial load but
may not eliminate everything.
What is disinfection?
Use of physical or chemical methods to reduce or kill many microbes on inanimate objects.
What is antisepsis?
Use of antimicrobial chemicals on living tissue, such as skin or mucosal surfaces.
What is an antiseptic?
A chemical agent safe enough to use on living tissue to reduce or kill microbes.
What is a disinfectant?
A chemical agent used on inanimate objects or surfaces to kill or reduce microbes.
What is sanitization?
Reduction of microbial numbers to levels considered safe by public health standards.
What is pasteurization?
Controlled heating of food or liquid to reduce microbial load without sterilizing it.
Does pasteurization sterilize?
No. Pasteurization reduces microbial load but does not eliminate all microbes.
Answers
What are the four biosafety laboratory containment levels?
BSL-1, BSL-2, BSL-3, and BSL-4.
What does BSL stand for?
Biosafety Level.
What determines the biosafety level needed for a microbe?
Risk of containment failure, severity of infection, origin of microbe, host specificity, route of
exposure, transmissibility, and type of lab work.
What type of organisms are handled in BSL-1 labs?
Microbes that do not usually cause disease in healthy humans.
Give examples of BSL-1 microbes.
Lab-adapted nonpathogenic E. coli, Lactobacillus acidophilus, and Bacillus thuringiensis.
What are standard BSL-1 practices?
Handwashing, disinfecting surfaces, no eating/drinking/cosmetics, and routine
decontamination of work areas.
What type of organisms are handled in BSL-2 labs?
Moderately biohazardous agents that can cause harm.
Give examples of BSL-2 microbes.
,Bordetella pertussis, pathogenic E. coli, Salmonella, and Staphylococcus.
What safety practices are used in BSL-2 labs?
PPE, biosafety cabinets, limited access, sharps precautions, and trained personnel only.
What type of organisms are handled in BSL-3 labs?
Highly pathogenic, infectious, or toxic microbes that can cause serious disease but often have
treatments.
Give examples of BSL-3 microbes.
Bacillus anthracis, SARS-CoV-2, Mycobacterium tuberculosis, influenza virus, and Yersinia
pestis.
What facility features are important in BSL-3 labs?
HEPA-filtered exhaust air, double-door entry, biosafety cabinets, PPE, and negative air
pressure.
Why does a BSL-3 lab use negative pressure?
So air flows into the lab when doors open instead of allowing pathogens to escape outward.
What type of organisms are handled in BSL-4 labs?
Highly infectious pathogens that cause deadly disease and usually lack effective treatments.
Give examples of BSL-4 pathogens.
Ebola virus, Marburg virus, Lassa virus, and engineered 1918 influenza.
What safety features are used in BSL-4 labs?
Isolated facilities, special air handling, sealed airlocks, decontamination showers, UV rooms,
and positive-pressure suits with HEPA-filtered air.
, What is sterilization?
Complete removal or destruction of all forms of microbial life from an object, surface, or
fluid.
Is sterilization the same as disinfection?
No. Sterilization removes all microbial life, while disinfection reduces microbial load but
may not eliminate everything.
What is disinfection?
Use of physical or chemical methods to reduce or kill many microbes on inanimate objects.
What is antisepsis?
Use of antimicrobial chemicals on living tissue, such as skin or mucosal surfaces.
What is an antiseptic?
A chemical agent safe enough to use on living tissue to reduce or kill microbes.
What is a disinfectant?
A chemical agent used on inanimate objects or surfaces to kill or reduce microbes.
What is sanitization?
Reduction of microbial numbers to levels considered safe by public health standards.
What is pasteurization?
Controlled heating of food or liquid to reduce microbial load without sterilizing it.
Does pasteurization sterilize?
No. Pasteurization reduces microbial load but does not eliminate all microbes.
