12 BIOD 171 : MODULE 5 EXAM STUDY GUIDE
1. Define the concept of universal precautions. ANS 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 assessing an
unknown microbial sample. ANS
1. size and shape
2. gram status
3. any observable motility
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?
ANS You 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.
4.A facultative anaerobe is a microorganism capable of growth under what conditions?
ANS It is capable of growth under both anaerobic and aerobic conditions
,12 BIOD 171 : MODULE 5 EXAM STUDY GUIDE
5.As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? ANS It would die. Because it is catalase negative it wouldn't be able
to breakdown peroxides.
6.Streptococcus is most often streaked onto:
- Chocolate agar
- EMB agar
- Blood agar
- Spirit Blue agar
- ANS Blood agar Strep is often cultured on Blood agar plates to determine its hemolytic
properties, which aids in the classification (and differentiation) process.
7.True or False. The Lancefield groups are used to subdivide antigenic groups of
gammahemolytic Streptococcus. ANS False The Lancefield groupings are used to
subdivide beta-hemolytic Strep
8.Greater than 90% of all human streptococcal infections belong to:
- Group C - Group B
1. Define the concept of universal precautions. ANS 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 assessing an
unknown microbial sample. ANS
1. size and shape
2. gram status
3. any observable motility
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?
ANS You 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.
4.A facultative anaerobe is a microorganism capable of growth under what conditions?
ANS It is capable of growth under both anaerobic and aerobic conditions
,12 BIOD 171 : MODULE 5 EXAM STUDY GUIDE
5.As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why? ANS It would die. Because it is catalase negative it wouldn't be able
to breakdown peroxides.
6.Streptococcus is most often streaked onto:
- Chocolate agar
- EMB agar
- Blood agar
- Spirit Blue agar
- ANS Blood agar Strep is often cultured on Blood agar plates to determine its hemolytic
properties, which aids in the classification (and differentiation) process.
7.True or False. The Lancefield groups are used to subdivide antigenic groups of
gammahemolytic Streptococcus. ANS False The Lancefield groupings are used to
subdivide beta-hemolytic Strep
8.Greater than 90% of all human streptococcal infections belong to:
- Group C - Group B
