BIOD 171: MODULE 5 - PRACTICE
SELF EXAM QUESTIONS AND
ANSWERS 2025
, The concept of treating all samples, whether known or unknown, as potentially
hazardous (or pathogenic) materials is known as __________. - ANSWERUniversal
precautions
List at least 3 observations a researcher would be sure to note while assessing an
unknown microbial sample. - ANSWERA lab researcher would be certain to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
4. The presence of any chemical reactions
5. Changes in color localized to the organism or the surrounding media
6. Capture (or draw) images of any of the characteristics described above
While observing an unknown sample of limited amounts, a researcher must determine
the following observations:
(1) The presence of any motility and
(2) its Gram status using the same sample—the liquid cannot be divided.
Which would you determine first and why? - ANSWERYou must determine motility
before determining the Gram status. Motility requires a wet mount, while Gram staining
requires heat fixing the sample. If one were to begin with the gram stain, the heat
fixation process would kill the organism, making any observations regarding motility
impossible. The correct approach would be to place the liquid culture on a glass slide
and determine its motility status. Next, the same liquid culture can be heat fixed and
gram stained,
A facultative anaerobe is a microorganism capable of growth under what conditions? -
ANSWERA facultative anaerobe is capable of growth under aerobic (with oxygen) and
anaerobic (without oxygen) conditions.
As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? - ANSWERStreptococcus would not survive in the presence of
peroxides—it is unable to breakdown peroxides (catalase negative). Left unchecked,
peroxides would damage the cellular integrity of Strep causing lysis/cell death.
Streptococcus is most often streaked onto:
A. Chocolate agar
B. EMB agar
SELF EXAM QUESTIONS AND
ANSWERS 2025
, The concept of treating all samples, whether known or unknown, as potentially
hazardous (or pathogenic) materials is known as __________. - ANSWERUniversal
precautions
List at least 3 observations a researcher would be sure to note while assessing an
unknown microbial sample. - ANSWERA lab researcher would be certain to note:
1. Size and shape
2. Any observable motility
3. Gram status (positive or negative)
4. The presence of any chemical reactions
5. Changes in color localized to the organism or the surrounding media
6. Capture (or draw) images of any of the characteristics described above
While observing an unknown sample of limited amounts, a researcher must determine
the following observations:
(1) The presence of any motility and
(2) its Gram status using the same sample—the liquid cannot be divided.
Which would you determine first and why? - ANSWERYou must determine motility
before determining the Gram status. Motility requires a wet mount, while Gram staining
requires heat fixing the sample. If one were to begin with the gram stain, the heat
fixation process would kill the organism, making any observations regarding motility
impossible. The correct approach would be to place the liquid culture on a glass slide
and determine its motility status. Next, the same liquid culture can be heat fixed and
gram stained,
A facultative anaerobe is a microorganism capable of growth under what conditions? -
ANSWERA facultative anaerobe is capable of growth under aerobic (with oxygen) and
anaerobic (without oxygen) conditions.
As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? - ANSWERStreptococcus would not survive in the presence of
peroxides—it is unable to breakdown peroxides (catalase negative). Left unchecked,
peroxides would damage the cellular integrity of Strep causing lysis/cell death.
Streptococcus is most often streaked onto:
A. Chocolate agar
B. EMB agar
