STRAIGHTERLINE MICROBIOLOGY 250
CERTIFICATION EVALUATION 2026 EXAM
QUESTIONS AND SOLUTIONS
◉ Thioglycolate medium contains the following: yeast extract,
pancreatic digest of casein, glucose, L-cysteine, sodium chloride,
sodium thioglycolate, and agar. It is considered a complex medium
because
Select one:
a. both yeast extract and pancreatic digest of casein are not
chemically defined.
b. it has multiple ingredients for a broad range of nutrients.
c. depending on their oxygen utilization pattern, organisms will
grow differently on it.
d. thioglycolate has a carbon-sulfur bond that many microbes
cannot break enzymatically.
Answer: both yeast extract and pancreatic digest of casein are not
chemically defined.
◉ Table 3.6 in your textbook uses Paramecium to illustrate several
types of light microscopy. Each image is magnified 230X and
,measures about 4 cm. The actual size of a Paramecium is about
______.
Select one:
a. 175 μm
b. 0.2 μm
c. 4,000 μm
d. 920 μm
e. 57.5 μm.
Answer: 175 μm
◉ In the experiments constructed by Pasteur to disprove
spontaneous generation, swan-necked flasks were used. Why was
this shape of flask used in this experiment?
Select one:
a. The glass necks needed to be open to the air, yet constructed so
that bacteria would settle in the lowest part of the neck.
b. These flask shapes were the easiest and cheapest to produce.
c. The shape of the glass neck allowed the bacteria into the flask and
then into the media, but air could not enter.
d. Because the glass necks were stretched out, the heat used to
sterilize the medium inside of the flask could not kill the bacteria in
the neck..
,Answer: The glass necks needed to be open to the air, yet
constructed so that bacteria would settle in the lowest part of the
neck.
◉ A pure culture contains
Select one:
a. only one identified species of microorganism.
b. only bacteria.
c. microbes from a single source.
d. a variety of species from the same genus..
Answer: only one identified species of microorganism.
◉ Which of the following parts of a microscope magnifies the
specimen to produce a real image of the specimen?
Select one:
a. Condenser
b. Objective lens
c. Ocular lens
d. Body
e. Nosepiece.
Answer: Objective lens
, ◉ In the cell cytoplasm, molecules of ATP are a ______.
Select one:
a. solute
b. solvent.
Answer: solute
◉ All cells contain
Select one:
a. ribosomes for protein synthesis.
b. cell walls made of cellulose.
c. uracil in their DNA.
d. organelles for compartmentalization.
e. mitochondria to generate ATP..
Answer: ribosomes for protein synthesis.
◉ What would be the valence number of electrons in the sulfur (S)
atom? Its atomic number is 16.
Select one:
a. 2
b. 6
c. 8
d. 16
CERTIFICATION EVALUATION 2026 EXAM
QUESTIONS AND SOLUTIONS
◉ Thioglycolate medium contains the following: yeast extract,
pancreatic digest of casein, glucose, L-cysteine, sodium chloride,
sodium thioglycolate, and agar. It is considered a complex medium
because
Select one:
a. both yeast extract and pancreatic digest of casein are not
chemically defined.
b. it has multiple ingredients for a broad range of nutrients.
c. depending on their oxygen utilization pattern, organisms will
grow differently on it.
d. thioglycolate has a carbon-sulfur bond that many microbes
cannot break enzymatically.
Answer: both yeast extract and pancreatic digest of casein are not
chemically defined.
◉ Table 3.6 in your textbook uses Paramecium to illustrate several
types of light microscopy. Each image is magnified 230X and
,measures about 4 cm. The actual size of a Paramecium is about
______.
Select one:
a. 175 μm
b. 0.2 μm
c. 4,000 μm
d. 920 μm
e. 57.5 μm.
Answer: 175 μm
◉ In the experiments constructed by Pasteur to disprove
spontaneous generation, swan-necked flasks were used. Why was
this shape of flask used in this experiment?
Select one:
a. The glass necks needed to be open to the air, yet constructed so
that bacteria would settle in the lowest part of the neck.
b. These flask shapes were the easiest and cheapest to produce.
c. The shape of the glass neck allowed the bacteria into the flask and
then into the media, but air could not enter.
d. Because the glass necks were stretched out, the heat used to
sterilize the medium inside of the flask could not kill the bacteria in
the neck..
,Answer: The glass necks needed to be open to the air, yet
constructed so that bacteria would settle in the lowest part of the
neck.
◉ A pure culture contains
Select one:
a. only one identified species of microorganism.
b. only bacteria.
c. microbes from a single source.
d. a variety of species from the same genus..
Answer: only one identified species of microorganism.
◉ Which of the following parts of a microscope magnifies the
specimen to produce a real image of the specimen?
Select one:
a. Condenser
b. Objective lens
c. Ocular lens
d. Body
e. Nosepiece.
Answer: Objective lens
, ◉ In the cell cytoplasm, molecules of ATP are a ______.
Select one:
a. solute
b. solvent.
Answer: solute
◉ All cells contain
Select one:
a. ribosomes for protein synthesis.
b. cell walls made of cellulose.
c. uracil in their DNA.
d. organelles for compartmentalization.
e. mitochondria to generate ATP..
Answer: ribosomes for protein synthesis.
◉ What would be the valence number of electrons in the sulfur (S)
atom? Its atomic number is 16.
Select one:
a. 2
b. 6
c. 8
d. 16
