1|Page
ASU MIC 205 PENTON EXAM 1 NEWEST 2025/2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED||
why doesn't penicillin harm eukaryotes? - ANSWER-Eukaryotic
cells, such as human cells, do not possess peptidoglycan in their
cell walls. Instead, they have a different cellular structure,
primarily consisting of a cell membrane. Since penicillin
specifically targets the bacterial cell wall, it does not affect
eukaryotic cells, making it safe for use as an antibiotic in humans
and other eukaryotes.
What does an acid-fast stains - ANSWER-differentiate cells with a
waxy cell wall that contains high amounts of mycolic acid
This stain differentiates bacterial cells based on their ability to
retain the primary stain, carbol fuchsin, despite being washed with
an acid-alcohol solution.
How does acid fast stain differentiate bacterial cells? - ANSWER-
During the staining process, non-acid-fast bacteria lose the carbol
fuchsin stain when treated with acid-alcohol, while acid-fast
bacteria retain it.
,2|Page
Color of Acid-Fast Organisms - ANSWER-After the staining
process, acid-fast organisms appear red or pink, while non-acid-
fast organisms take on the color of the counterstain, which is
typically blue (like methylene blue).
Name an acid-fast organism - ANSWER-Mycobacterium
tuberculosis
Mycobacterium leprae
Is a Schaeffer-Fulton stain a differential stain or a simple stain? -
ANSWER-Differentiation stain
Why is Schaeffer Fulton stain a differential stain - ANSWER-it
allows for the differentiation between vegetative bacterial cells
and endospores based on their structural characteristics and
staining properties.
Malachite green: specifically stains endospores
Safranin: Stains the vegetative cells
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What color do endospores turn after Schaeffer Fulton stain -
ANSWER-Malachite green
what color do Vegative cells appear after Schaeffer Fulton stain -
ANSWER-Pink from safranin
What has to be done tothe proteins in the cell membrane in order
to drive the primary stain into the endospore? - ANSWER-To drive
the primary stain (malachite green) into the endospore during the
Schaeffer-Fulton staining procedure, the proteins in the cell
membrane of the endospore must be denatured. This is
accomplished by applying heat during the staining process.
What is an endospore? - ANSWER-a dormant, tough, and
temporarily non-reproductive structure produced by certain
bacteria.
Why do bacteria make endospores - ANSWER-to survive in
unfavorable environments
they can form endospores to protect their genetic material and
essential cellular components until conditions improve.
, 4|Page
ex. depleted nutrients, extreme temps
What bacterial group discussed in class is medically important
and form endospores?How does this relate to C. diff? - ANSWER-
Bacteria that form endospores such as bacillus and clostridia
Is relevant medically because its resistant to treatment and can
cause death
It relates to C diff because they both are both G+, have
endospores that are hard to treat and have the same symptoms
What does it mean for a bacterial growth medium to be selective?
- ANSWER-A selective growth medium is designed to inhibit the
growth of certain types of bacteria while allowing others to grow
This is achieved through the addition of specific substances, such
as antibiotics or specific nutrients, that favor the growth of target
organisms
What does it mean for a bacterial growth medium to be
differential? - ANSWER-allows multiple types of bacteria to grow
but contains specific indicators that help distinguish between them
based on their biochemical characteristics. These indicators can
ASU MIC 205 PENTON EXAM 1 NEWEST 2025/2026 ACTUAL EXAM
WITH COMPLETE QUESTIONS AND CORRECT DETAILED ANSWERS
(100% VERIFIED ANSWERS) |ALREADY GRADED A+| ||PROFESSOR
VERIFIED||
why doesn't penicillin harm eukaryotes? - ANSWER-Eukaryotic
cells, such as human cells, do not possess peptidoglycan in their
cell walls. Instead, they have a different cellular structure,
primarily consisting of a cell membrane. Since penicillin
specifically targets the bacterial cell wall, it does not affect
eukaryotic cells, making it safe for use as an antibiotic in humans
and other eukaryotes.
What does an acid-fast stains - ANSWER-differentiate cells with a
waxy cell wall that contains high amounts of mycolic acid
This stain differentiates bacterial cells based on their ability to
retain the primary stain, carbol fuchsin, despite being washed with
an acid-alcohol solution.
How does acid fast stain differentiate bacterial cells? - ANSWER-
During the staining process, non-acid-fast bacteria lose the carbol
fuchsin stain when treated with acid-alcohol, while acid-fast
bacteria retain it.
,2|Page
Color of Acid-Fast Organisms - ANSWER-After the staining
process, acid-fast organisms appear red or pink, while non-acid-
fast organisms take on the color of the counterstain, which is
typically blue (like methylene blue).
Name an acid-fast organism - ANSWER-Mycobacterium
tuberculosis
Mycobacterium leprae
Is a Schaeffer-Fulton stain a differential stain or a simple stain? -
ANSWER-Differentiation stain
Why is Schaeffer Fulton stain a differential stain - ANSWER-it
allows for the differentiation between vegetative bacterial cells
and endospores based on their structural characteristics and
staining properties.
Malachite green: specifically stains endospores
Safranin: Stains the vegetative cells
,3|Page
What color do endospores turn after Schaeffer Fulton stain -
ANSWER-Malachite green
what color do Vegative cells appear after Schaeffer Fulton stain -
ANSWER-Pink from safranin
What has to be done tothe proteins in the cell membrane in order
to drive the primary stain into the endospore? - ANSWER-To drive
the primary stain (malachite green) into the endospore during the
Schaeffer-Fulton staining procedure, the proteins in the cell
membrane of the endospore must be denatured. This is
accomplished by applying heat during the staining process.
What is an endospore? - ANSWER-a dormant, tough, and
temporarily non-reproductive structure produced by certain
bacteria.
Why do bacteria make endospores - ANSWER-to survive in
unfavorable environments
they can form endospores to protect their genetic material and
essential cellular components until conditions improve.
, 4|Page
ex. depleted nutrients, extreme temps
What bacterial group discussed in class is medically important
and form endospores?How does this relate to C. diff? - ANSWER-
Bacteria that form endospores such as bacillus and clostridia
Is relevant medically because its resistant to treatment and can
cause death
It relates to C diff because they both are both G+, have
endospores that are hard to treat and have the same symptoms
What does it mean for a bacterial growth medium to be selective?
- ANSWER-A selective growth medium is designed to inhibit the
growth of certain types of bacteria while allowing others to grow
This is achieved through the addition of specific substances, such
as antibiotics or specific nutrients, that favor the growth of target
organisms
What does it mean for a bacterial growth medium to be
differential? - ANSWER-allows multiple types of bacteria to grow
but contains specific indicators that help distinguish between them
based on their biochemical characteristics. These indicators can
