Microbiology Ch 7 Exam Questions And Correct Answers
Which of the following lists the moist heat methods in order of temperature used (highest
to lowest)? Answer: Ultrahigh>Auoclave>Boiling>Batch Pasteurization
_______________ is a process used to destroy pathogens in food and drinks. It must be
done at a lower temperature than other methods so that _______________. - Answer
Pasteurization; the taste of the food or drink will not be altered
Environmentalis: If well water for a community is contaminated during a flood with a
pathogenic fungus, will the residents be safe if they boil the water before drinking it for 15
minutes? Yes, most likely
Before drawing blood from an individual who wants to donate blood, a nurse would
prepare the arm by scrubbing it with a Betadine solution. Such a form of antimicrobial
control would be termed __________. Answer Antisepsis
Destruction of vegetative pathogens on living tissue is defined as antisepsis.
When microbial control methods are employed microbes are destroyed at a constant rate;
there is no instantaneous death of all the microbes present. That microbial death rate is
influenced by all of the following factors EXCEPT __________. - Answer toxins produced
by the microbe
Although microbial toxins can impact the state of an infection, these factors do not
impact the mortality rate of the organism.
Methods of microbial control typically rely on any of the following structures of the
microbe EXCEPT which one? - Answer mitochondria
Many of the target organisms are bacteria or viruses, neither of which possess
mitochondria. Furthermore, microbial control mechanisms strive to target structures of
microbes that are not found in human cells.
, Which of the following physical methods of microbial control denatures proteins as
mechanism of action? - Answer boiling or autoclaving
Heat denatures proteins by altering the tertiary structure, thus inactivating the function of
the protein.
Gluteraldehydes are some of the most effective chemical control agents because they
__________. - Answer are relatively safe, yet considered a sterilizing agent
Given adequate exposure time, gluteraldehydes inactivate microbial proteins even in
small concentrations and are regarded as bactericidal, tuberculocidal, virucidal, and
sporicidal, though they cause less irritation to living tissue. Since it is a liquid, it is an
agent with extreme versatility for all kinds of hospital equipment.
Contaminated hospital equipment represents a difficult environment in which to control
unwanted microbial growth. Regarding factors that affect disinfection of hospital
equipment, which of the following statements is CORRECT? - Answer The cell wall of
gram-negative bacteria is peculiarly resistant to most chemicals applied to kill microbes.
A major cause of this relative resistance to biocides is the outer lipopolysaccharide layer
of gram-negative bacteria.
Consider several actions of moist and dry heat to control microbial growth. Which of the
following methods would be the best way to reduce microbes without changing the taste
and the chemical composition of beer? - Answer pasteurization
Pasteurization retains the properties of the alcohol and the protein structure. Though it
does not destroy all microbes, it is sufficient for destroying most of the harmful microbes
while retaining flavor.
Surface-active agents act by lowering surface tension so that microbes can be more
easily removed. All of the following agents use this mechanism of action EXCEPT
__________. - Answer halogens
This is the exception. The mode of action for halogens includes inhibition of proteins
and acting as a strong oxidizing agent, but halogens do not act as surface-active agents.
Compare the following chemical agents with respect to effectiveness against endospores
and mycobacteria. For a clinical situation in which it is desirable to control the growth of
microbes containing both mycobacteria and endospores, which chemical agent would
Which of the following lists the moist heat methods in order of temperature used (highest
to lowest)? Answer: Ultrahigh>Auoclave>Boiling>Batch Pasteurization
_______________ is a process used to destroy pathogens in food and drinks. It must be
done at a lower temperature than other methods so that _______________. - Answer
Pasteurization; the taste of the food or drink will not be altered
Environmentalis: If well water for a community is contaminated during a flood with a
pathogenic fungus, will the residents be safe if they boil the water before drinking it for 15
minutes? Yes, most likely
Before drawing blood from an individual who wants to donate blood, a nurse would
prepare the arm by scrubbing it with a Betadine solution. Such a form of antimicrobial
control would be termed __________. Answer Antisepsis
Destruction of vegetative pathogens on living tissue is defined as antisepsis.
When microbial control methods are employed microbes are destroyed at a constant rate;
there is no instantaneous death of all the microbes present. That microbial death rate is
influenced by all of the following factors EXCEPT __________. - Answer toxins produced
by the microbe
Although microbial toxins can impact the state of an infection, these factors do not
impact the mortality rate of the organism.
Methods of microbial control typically rely on any of the following structures of the
microbe EXCEPT which one? - Answer mitochondria
Many of the target organisms are bacteria or viruses, neither of which possess
mitochondria. Furthermore, microbial control mechanisms strive to target structures of
microbes that are not found in human cells.
, Which of the following physical methods of microbial control denatures proteins as
mechanism of action? - Answer boiling or autoclaving
Heat denatures proteins by altering the tertiary structure, thus inactivating the function of
the protein.
Gluteraldehydes are some of the most effective chemical control agents because they
__________. - Answer are relatively safe, yet considered a sterilizing agent
Given adequate exposure time, gluteraldehydes inactivate microbial proteins even in
small concentrations and are regarded as bactericidal, tuberculocidal, virucidal, and
sporicidal, though they cause less irritation to living tissue. Since it is a liquid, it is an
agent with extreme versatility for all kinds of hospital equipment.
Contaminated hospital equipment represents a difficult environment in which to control
unwanted microbial growth. Regarding factors that affect disinfection of hospital
equipment, which of the following statements is CORRECT? - Answer The cell wall of
gram-negative bacteria is peculiarly resistant to most chemicals applied to kill microbes.
A major cause of this relative resistance to biocides is the outer lipopolysaccharide layer
of gram-negative bacteria.
Consider several actions of moist and dry heat to control microbial growth. Which of the
following methods would be the best way to reduce microbes without changing the taste
and the chemical composition of beer? - Answer pasteurization
Pasteurization retains the properties of the alcohol and the protein structure. Though it
does not destroy all microbes, it is sufficient for destroying most of the harmful microbes
while retaining flavor.
Surface-active agents act by lowering surface tension so that microbes can be more
easily removed. All of the following agents use this mechanism of action EXCEPT
__________. - Answer halogens
This is the exception. The mode of action for halogens includes inhibition of proteins
and acting as a strong oxidizing agent, but halogens do not act as surface-active agents.
Compare the following chemical agents with respect to effectiveness against endospores
and mycobacteria. For a clinical situation in which it is desirable to control the growth of
microbes containing both mycobacteria and endospores, which chemical agent would
