BIOD 171 EXAM MODULE 5
. Define the concept of universal precautions.
Universal precautions means any and all samples, whether known or unknown, are to betreated as
potentially hazardous (or pathogenic) materials.
2. List at least 3 observations a researcher would be sure to note while assessing an unknownmicrobial
sample.
A 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
Exam Page 2
Answer Key
1. 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 aglass slide and determine its motility status. Next, the
same liquid culture can be heat fixed and Gram stained.
2. A facultative anaerobe is a microorganism capable of growth under what conditions?
Exam Page 3
A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic(without oxygen)
Answer Key
conditions.
1. True or False. The Lancefield groups are used to subdivide antigenic groups of alpha-hemolytic
Streptococcus.
False. The Lancefield groupings are used to subdivide beta-hemolytic Strep.
2. The distinctions for Lancefield subgroupings lie in its: (select all that apply)
A. Catalase activity
B. Carbohydrate composition of antigens
C. Hemolytic activity
D. All of the above
. Define the concept of universal precautions.
Universal precautions means any and all samples, whether known or unknown, are to betreated as
potentially hazardous (or pathogenic) materials.
2. List at least 3 observations a researcher would be sure to note while assessing an unknownmicrobial
sample.
A 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
Exam Page 2
Answer Key
1. 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 aglass slide and determine its motility status. Next, the
same liquid culture can be heat fixed and Gram stained.
2. A facultative anaerobe is a microorganism capable of growth under what conditions?
Exam Page 3
A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic(without oxygen)
Answer Key
conditions.
1. True or False. The Lancefield groups are used to subdivide antigenic groups of alpha-hemolytic
Streptococcus.
False. The Lancefield groupings are used to subdivide beta-hemolytic Strep.
2. The distinctions for Lancefield subgroupings lie in its: (select all that apply)
A. Catalase activity
B. Carbohydrate composition of antigens
C. Hemolytic activity
D. All of the above
