BIOD 171 : MODULE 5 EXAM 100%
SOLVED
, Define the concept of universal precautions. - ANSWERUniversal precautions means
any and all samples, whether known or unknown, are to be treated as potentially
hazardous (or pathogenic) materials.
List at least 3 observations a researcher would be sure to note while assessing an
unknown microbial sample. - ANSWER1. size and shape
2. gram status
3. any observable motility
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? - ANSWERYou would need to determine the motility first and then the Gram
status. Motility requires a wet mount and Gram staining requires heat fixing the sample.
If you perform a Gram stain first the heat fixation would kill the organism, making it
impossible to observe motility.
A facultative anaerobe is a microorganism capable of growth under what conditions? -
ANSWERIt is capable of growth under both anaerobic and aerobic conditions
As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? - ANSWERIt would die. Because it is catalase negative it wouldn't be
able to breakdown peroxides.
Streptococcus is most often streaked onto:
- Chocolate agar
- EMB agar
- Blood agar
- Spirit Blue agar - ANSWERBlood agar
Strep is often cultured on Blood agar plates to determine its hemolytic properties, which
aids in the classification (and differentiation) process.
True or False. The Lancefield groups are used to subdivide antigenic groups of gamma-
hemolytic Streptococcus. - ANSWERFalse
The Lancefield groupings are used to subdivide beta-hemolytic Strep
Greater than 90% of all human streptococcal infections belong to:
- Group C
- Group B
- Group A
SOLVED
, Define the concept of universal precautions. - ANSWERUniversal precautions means
any and all samples, whether known or unknown, are to be treated as potentially
hazardous (or pathogenic) materials.
List at least 3 observations a researcher would be sure to note while assessing an
unknown microbial sample. - ANSWER1. size and shape
2. gram status
3. any observable motility
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? - ANSWERYou would need to determine the motility first and then the Gram
status. Motility requires a wet mount and Gram staining requires heat fixing the sample.
If you perform a Gram stain first the heat fixation would kill the organism, making it
impossible to observe motility.
A facultative anaerobe is a microorganism capable of growth under what conditions? -
ANSWERIt is capable of growth under both anaerobic and aerobic conditions
As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? - ANSWERIt would die. Because it is catalase negative it wouldn't be
able to breakdown peroxides.
Streptococcus is most often streaked onto:
- Chocolate agar
- EMB agar
- Blood agar
- Spirit Blue agar - ANSWERBlood agar
Strep is often cultured on Blood agar plates to determine its hemolytic properties, which
aids in the classification (and differentiation) process.
True or False. The Lancefield groups are used to subdivide antigenic groups of gamma-
hemolytic Streptococcus. - ANSWERFalse
The Lancefield groupings are used to subdivide beta-hemolytic Strep
Greater than 90% of all human streptococcal infections belong to:
- Group C
- Group B
- Group A
