1
Portage Microbiology Exam 4 Questions with
Correct Answers | Updated (100% Correct
Answers)
True or False: Growth media is best suited for distinguishing
between two similar species of bacteria Answer: False. Growth
media is designed to simply support (and not restrict) microbial
growth
A researcher is asked to determine which of two vials contains e coli
and which contains salmonella. Knowing both gram-negative while
only one of them is capable of fermenting lactose, which type of
media would be best suited (multiple choice) Answer: Differential
media distinguishes between two, often related, microbes
A researcher is asked to determine if a sample contains Neisseria
meningitides. Knowing Neisseria meningitides is slow growing and
other foreign microbes may also be present in the culture, which
type of media would be best suited? (multiple choice) Answer:
Selective media
What are the requirements of a fastidious microbe? (short answer)
Answer: A fastidious microbe is an organism with complex growth
requirements such that is absent it will not grow. Enriched medias
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thus contain these specific and essential nutrients required for the
growth of a particular subset of microorganisms.
True or False: LB agar is classified as a selective, non-differential
media Answer: False
What is agar used for in microbiology? (short answer) Answer: Agar
is used to create a solid, smooth surface on which microbes can
grow
Alpha hemolysis (matching) Answer: Incomplete hemolytic activity
Beta hemolysis (matching) Answer: Complete hemolytic activity
Gamma hemolysis (matching) Answer: no hemolytic activity
Columbia CNA agar is most closely related to which media (multiple
choice) Answer: blood agar
True or False: Chocolate agar gets its brown color from cocoa to
produce an enriched media Answer: false
True or False: Chocolate is not a component of chocolate agar
plates Answer: true
A researcher is studying a strain of e coli currently growing on a
MacConkey plate. However, the researcher can't remember if e coli
is gram positive or gram negative. Would a gram stain be necessary
to confirm? Why or why not? (short answer) Answer: No. A gram
© 2025 All rights reserved
Portage Microbiology Exam 4 Questions with
Correct Answers | Updated (100% Correct
Answers)
True or False: Growth media is best suited for distinguishing
between two similar species of bacteria Answer: False. Growth
media is designed to simply support (and not restrict) microbial
growth
A researcher is asked to determine which of two vials contains e coli
and which contains salmonella. Knowing both gram-negative while
only one of them is capable of fermenting lactose, which type of
media would be best suited (multiple choice) Answer: Differential
media distinguishes between two, often related, microbes
A researcher is asked to determine if a sample contains Neisseria
meningitides. Knowing Neisseria meningitides is slow growing and
other foreign microbes may also be present in the culture, which
type of media would be best suited? (multiple choice) Answer:
Selective media
What are the requirements of a fastidious microbe? (short answer)
Answer: A fastidious microbe is an organism with complex growth
requirements such that is absent it will not grow. Enriched medias
© 2025 All rights reserved
, 2
thus contain these specific and essential nutrients required for the
growth of a particular subset of microorganisms.
True or False: LB agar is classified as a selective, non-differential
media Answer: False
What is agar used for in microbiology? (short answer) Answer: Agar
is used to create a solid, smooth surface on which microbes can
grow
Alpha hemolysis (matching) Answer: Incomplete hemolytic activity
Beta hemolysis (matching) Answer: Complete hemolytic activity
Gamma hemolysis (matching) Answer: no hemolytic activity
Columbia CNA agar is most closely related to which media (multiple
choice) Answer: blood agar
True or False: Chocolate agar gets its brown color from cocoa to
produce an enriched media Answer: false
True or False: Chocolate is not a component of chocolate agar
plates Answer: true
A researcher is studying a strain of e coli currently growing on a
MacConkey plate. However, the researcher can't remember if e coli
is gram positive or gram negative. Would a gram stain be necessary
to confirm? Why or why not? (short answer) Answer: No. A gram
© 2025 All rights reserved
