BIOL 271 MICROBIOLOGY W/ LAB
MODULE 4 EXAM 2026/2027 WITH 100
QUESTIONS AND EXPERT-VERIFIED
CORRECT ANSWERS | ALREADY
GRADED A+ | GUARANTEED PASS
1. 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.
2. A researcher is asked to determine which of two vials contains E. coli and
which contains Salmonella. Knowing both are Gram-negative while only one
is capable of fermenting lactose, which type of media would be best suited?
Answer: Differential media. Differential media distinguishes between two often-
related microbes.
3. A researcher is asked to determine if a sample contains Neisseria
meningitidis. Knowing N. meningitidis is slow growing and other foreign
microbes may also be present, which type of media would be best suited?
Answer: Selective media.
, 4. True or False: LB agar is classified as a selective, non-differential media.
Answer: False. LB agar is the most basic type of agar and supports the growth of
virtually all microbes without restriction.
5. What is agar used for in microbiology?
Answer: Agar is used to create a solid, smooth surface on which microbes can
grow.
6. Blood agar is which type of medium? (Select all that apply.)
Answer: Differential and Enriched.
7. Columbia CNA agar is most closely related to which media?
Answer: Blood agar.
8. True or False: Chocolate agar gets its brown color from cocoa to produce
an enriched media.
Answer: False.
9. True or False: Chocolate is not a component of chocolate agar plates.
Answer: True.
10. When given an unknown bacterial sample, the first step is to expand the
current bacterial population. Which form of media best suits this need?
A. MSA agar
B. LB media containing ampicillin and neomycin
C. MacConkey agar
D. Blood agar
Answer: D. Blood agar. All other options are selective and will inhibit growth of
the unknown sample.
11. True or False: Differential media is best suited for distinguishing between
two similar species of bacteria.
Answer: True.
12. An unknown microbe is streaked onto a MacConkey agar plate. After
overnight incubation at 37°C, growth is observed. Would a Gram stain be
necessary? Why or why not?
Answer: No, a Gram stain would not be necessary because only Gram-negative
microbes will grow on MacConkey agar.
MODULE 4 EXAM 2026/2027 WITH 100
QUESTIONS AND EXPERT-VERIFIED
CORRECT ANSWERS | ALREADY
GRADED A+ | GUARANTEED PASS
1. 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.
2. A researcher is asked to determine which of two vials contains E. coli and
which contains Salmonella. Knowing both are Gram-negative while only one
is capable of fermenting lactose, which type of media would be best suited?
Answer: Differential media. Differential media distinguishes between two often-
related microbes.
3. A researcher is asked to determine if a sample contains Neisseria
meningitidis. Knowing N. meningitidis is slow growing and other foreign
microbes may also be present, which type of media would be best suited?
Answer: Selective media.
, 4. True or False: LB agar is classified as a selective, non-differential media.
Answer: False. LB agar is the most basic type of agar and supports the growth of
virtually all microbes without restriction.
5. What is agar used for in microbiology?
Answer: Agar is used to create a solid, smooth surface on which microbes can
grow.
6. Blood agar is which type of medium? (Select all that apply.)
Answer: Differential and Enriched.
7. Columbia CNA agar is most closely related to which media?
Answer: Blood agar.
8. True or False: Chocolate agar gets its brown color from cocoa to produce
an enriched media.
Answer: False.
9. True or False: Chocolate is not a component of chocolate agar plates.
Answer: True.
10. When given an unknown bacterial sample, the first step is to expand the
current bacterial population. Which form of media best suits this need?
A. MSA agar
B. LB media containing ampicillin and neomycin
C. MacConkey agar
D. Blood agar
Answer: D. Blood agar. All other options are selective and will inhibit growth of
the unknown sample.
11. True or False: Differential media is best suited for distinguishing between
two similar species of bacteria.
Answer: True.
12. An unknown microbe is streaked onto a MacConkey agar plate. After
overnight incubation at 37°C, growth is observed. Would a Gram stain be
necessary? Why or why not?
Answer: No, a Gram stain would not be necessary because only Gram-negative
microbes will grow on MacConkey agar.
