Portage Microbiology BIOD171 Exam 5 Ques ons and
answers Newest RATED A+ 2025/2026 UPDATED
Define the concept of universal precau ons. - CORRECT ANSWERS Universal precau ons
means any and all samples, whether known or unknown, are to be treated as poten ally
hazardous (or pathogenic) materials.
List at least 3 observa ons a researcher would be sure to note while assessing an unknown
microbial sample. - CORRECT ANSWERS A lab researcher would be certain to note:
Size and shape
Any observable mo lity
Gram status (posi ve or nega ve)
The presence of any chemical reac ons
Changes in color localized to the organism or the surrounding media
Capture (or draw) images of any of the characteris cs described above
While observing an unknown sample of limited amounts, a researcher must determine the
following observa ons: (1) the presence of any mo lity and (2) its Gram status using the same
sample—the liquid sample cannot be divided. Which would you determine first and why? -
CORRECT ANSWERS You must determine mo lity before determining the Gram status. Mo lity
requires a wet mount, while Gram staining requires heat fixing the sample. If one were to begin
with the Gram stain the heat fixa on process would kill the organism, making any observa ons
regarding mo lity impossible. The correct approach would be to place the liquid culture on a
glass slide and determine its mo lity status. Next, the same liquid culture can be heat fixed and
Gram stained.
A faculta ve anaerobe is a microorganism capable of growth under what condi ons? -
CORRECT ANSWERS A faculta ve anaerobe is capable of growth under aerobic (with oxygen)
and anaerobic (without oxygen) condi ons.
, As Streptococcus is catalase nega ve would it thrive or die in the presence of peroxides? Why?
- CORRECT ANSWERS Streptococcus is catalse nega ve which means it cannot break down
peroxides and if any peroxides are present it would die.
Streptococcus is most o8en streaked onto: - CORRECT ANSWERS Blood agar
Strep is o8en cultured on Blood agar plates to determine its hemoly c proper es, which aids in
the classifica on (and differen a on) process.
True or False. The Lancefield groups are used to subdivide an genic groups of gamma-
hemoly c Streptococcus. - CORRECT ANSWERS False
The Lancefield groupings are used to subdivide beta-hemoly c Strep.
The dis nc ons for Lancefield subgroupings lie in its: (select all that apply)
Catalase ac vity
Hemoly c ac vity
Carbohydrate composi on of an gens
All of the above - CORRECT ANSWERS Carbohydrate composi on of an gens
Carbohydrate composi on of an gens present in the cell wall determines the Lancefield
groupings (A, B, C, etc). Note, ALL strep under Lancefield groupings are (by defini on) catalase
nega ve and beta-hemoly c. Thus, answers A and C cannot be used to subdivide streptococcal
species.
answers Newest RATED A+ 2025/2026 UPDATED
Define the concept of universal precau ons. - CORRECT ANSWERS Universal precau ons
means any and all samples, whether known or unknown, are to be treated as poten ally
hazardous (or pathogenic) materials.
List at least 3 observa ons a researcher would be sure to note while assessing an unknown
microbial sample. - CORRECT ANSWERS A lab researcher would be certain to note:
Size and shape
Any observable mo lity
Gram status (posi ve or nega ve)
The presence of any chemical reac ons
Changes in color localized to the organism or the surrounding media
Capture (or draw) images of any of the characteris cs described above
While observing an unknown sample of limited amounts, a researcher must determine the
following observa ons: (1) the presence of any mo lity and (2) its Gram status using the same
sample—the liquid sample cannot be divided. Which would you determine first and why? -
CORRECT ANSWERS You must determine mo lity before determining the Gram status. Mo lity
requires a wet mount, while Gram staining requires heat fixing the sample. If one were to begin
with the Gram stain the heat fixa on process would kill the organism, making any observa ons
regarding mo lity impossible. The correct approach would be to place the liquid culture on a
glass slide and determine its mo lity status. Next, the same liquid culture can be heat fixed and
Gram stained.
A faculta ve anaerobe is a microorganism capable of growth under what condi ons? -
CORRECT ANSWERS A faculta ve anaerobe is capable of growth under aerobic (with oxygen)
and anaerobic (without oxygen) condi ons.
, As Streptococcus is catalase nega ve would it thrive or die in the presence of peroxides? Why?
- CORRECT ANSWERS Streptococcus is catalse nega ve which means it cannot break down
peroxides and if any peroxides are present it would die.
Streptococcus is most o8en streaked onto: - CORRECT ANSWERS Blood agar
Strep is o8en cultured on Blood agar plates to determine its hemoly c proper es, which aids in
the classifica on (and differen a on) process.
True or False. The Lancefield groups are used to subdivide an genic groups of gamma-
hemoly c Streptococcus. - CORRECT ANSWERS False
The Lancefield groupings are used to subdivide beta-hemoly c Strep.
The dis nc ons for Lancefield subgroupings lie in its: (select all that apply)
Catalase ac vity
Hemoly c ac vity
Carbohydrate composi on of an gens
All of the above - CORRECT ANSWERS Carbohydrate composi on of an gens
Carbohydrate composi on of an gens present in the cell wall determines the Lancefield
groupings (A, B, C, etc). Note, ALL strep under Lancefield groupings are (by defini on) catalase
nega ve and beta-hemoly c. Thus, answers A and C cannot be used to subdivide streptococcal
species.
