MICR 271 EXAM 2 QUESTIONS AND
CORRECT ANSWERS!!
Plating and assays measures live/active bacteria/viruses but not the dead microbes.
Absorbance gives the total numbers of particles but no info on viability
Out of assay, plaques, or absorbance which distinguishes between live and dead cells
The use of chemical agents in the treatment of disease
Define Chemotherapy
A chemical substance or microorganism intended to destroy, deter, render harmless, or
exert a controlling effect on any harmful organism by chemical or biological means
Define biocide
The inhibition of microorganisms on or in living tissue
Define antisepsis
The reduction of total microbial populations to levels considered safe by public health
standards
Define sanitization
A substantial reduction of total microbial population and destruction of pathogens not
including spores
Define disinfection
All living cells, spores, viruses, and prions are either destroyed or removed from the
treatment environment
Define sterilization
Passed through the solution through a filter with small pore size, removing microbes
present
How are liquid solutions sterilized
, Using a biological safety cabinet, air enters the cabinet, is sterilized by passing through a
high efficiency particulate air filter before passing over the work surface in the cabinet
How is air filter sterilized
Resistance can be developed, which can increase antibiotic resistance
What is one problem that exists with including biocides in widely used preparations
Because most microbes require specific temperature ranges for optimal growth and
temperatures outside of that range can damage structures and alter chemical reactions
Why do moist and dry heated environments readily destroy bacteria, viruses, and fungi
An apparatus using steam under high pressure, routinely heated to 121 C for 20 minutes
What are autoclaves and what do they do
The ability to kill bacterial spores
What is used as the standard for ensuring sterilization using an autoclave
Causes thymine thymine dimerization
Why is UV radiation lethal
UV units are sometimes used to treat drinking water by allowing a thin layer of water to
pass under UV lamps
How is UV radiation sometimes used sterilization
Can penetrate deeply into objects, causing the formation of damaging free radicals that
react with nearby matter
How does ionizing radiation work
1. they do not work on viruses
2. antibiotics may be bactericidal (kills) or bacteriostatic (prevents further bacterial
replication)
3. an antibiotic must be selectively toxic (damage bacteria without damaging the host
what are the 3 basic principles of antibiotics
CORRECT ANSWERS!!
Plating and assays measures live/active bacteria/viruses but not the dead microbes.
Absorbance gives the total numbers of particles but no info on viability
Out of assay, plaques, or absorbance which distinguishes between live and dead cells
The use of chemical agents in the treatment of disease
Define Chemotherapy
A chemical substance or microorganism intended to destroy, deter, render harmless, or
exert a controlling effect on any harmful organism by chemical or biological means
Define biocide
The inhibition of microorganisms on or in living tissue
Define antisepsis
The reduction of total microbial populations to levels considered safe by public health
standards
Define sanitization
A substantial reduction of total microbial population and destruction of pathogens not
including spores
Define disinfection
All living cells, spores, viruses, and prions are either destroyed or removed from the
treatment environment
Define sterilization
Passed through the solution through a filter with small pore size, removing microbes
present
How are liquid solutions sterilized
, Using a biological safety cabinet, air enters the cabinet, is sterilized by passing through a
high efficiency particulate air filter before passing over the work surface in the cabinet
How is air filter sterilized
Resistance can be developed, which can increase antibiotic resistance
What is one problem that exists with including biocides in widely used preparations
Because most microbes require specific temperature ranges for optimal growth and
temperatures outside of that range can damage structures and alter chemical reactions
Why do moist and dry heated environments readily destroy bacteria, viruses, and fungi
An apparatus using steam under high pressure, routinely heated to 121 C for 20 minutes
What are autoclaves and what do they do
The ability to kill bacterial spores
What is used as the standard for ensuring sterilization using an autoclave
Causes thymine thymine dimerization
Why is UV radiation lethal
UV units are sometimes used to treat drinking water by allowing a thin layer of water to
pass under UV lamps
How is UV radiation sometimes used sterilization
Can penetrate deeply into objects, causing the formation of damaging free radicals that
react with nearby matter
How does ionizing radiation work
1. they do not work on viruses
2. antibiotics may be bactericidal (kills) or bacteriostatic (prevents further bacterial
replication)
3. an antibiotic must be selectively toxic (damage bacteria without damaging the host
what are the 3 basic principles of antibiotics
