Portage Microbiology BIOD171 Exam 5
1. Define the concept of universal precautions.: Universal precautions means any and all
samples, whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials.
2. List at least 3 observations a researcher would be sure to note while assess- ing
an unknown microbial sample.: A lab researcher would be certain to note:
Size and shape
Any observable motility
Gram status (positive or negative)
The presence of any chemical reactions
Changes in color localized to the organism or the surrounding media Capture (or
draw) images of any of the characteristics described above
3. 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 sample cannot be divided. Which
would you determine first and why?: You 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
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, same liquid culture can be heat fixed and Gram stained.
4. A facultative anaerobe is a microorganism capable of growth under what
conditions?: A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic (without oxygen)
conditions.
5. As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why?: Streptococcus is catalse negative which means it cannot break down peroxides and if any
peroxides are present it would die.
6. Streptococcus is most often streaked onto:: Blood agar
Strep is often cultured on Blood agar plates to determine its hemolytic properties, which aids in the classification (and ditterentiation)
process.
7. True or False. The Lancefield groups are used to subdivide antigenic groups of
gamma-hemolytic Streptococcus.: False
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1. Define the concept of universal precautions.: Universal precautions means any and all
samples, whether known or unknown, are to be treated as potentially hazardous (or pathogenic) materials.
2. List at least 3 observations a researcher would be sure to note while assess- ing
an unknown microbial sample.: A lab researcher would be certain to note:
Size and shape
Any observable motility
Gram status (positive or negative)
The presence of any chemical reactions
Changes in color localized to the organism or the surrounding media Capture (or
draw) images of any of the characteristics described above
3. 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 sample cannot be divided. Which
would you determine first and why?: You 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
1/
10
, same liquid culture can be heat fixed and Gram stained.
4. A facultative anaerobe is a microorganism capable of growth under what
conditions?: A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic (without oxygen)
conditions.
5. As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why?: Streptococcus is catalse negative which means it cannot break down peroxides and if any
peroxides are present it would die.
6. Streptococcus is most often streaked onto:: Blood agar
Strep is often cultured on Blood agar plates to determine its hemolytic properties, which aids in the classification (and ditterentiation)
process.
7. True or False. The Lancefield groups are used to subdivide antigenic groups of
gamma-hemolytic Streptococcus.: False
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10
