Portage Microbiology BIOD 171 Exam 5
Questions and Guide Answers
100% Verified Graded A+
1. The concept of treating all samples, whether known or unknown, as po-
tentially hazardous (or pathogenic) materials is known as
Answer: universal precautions
2. List at least 3 observations a researcher would be sure to note while assess-
ing an unknown microbial sample.
Answer: 1. any motility
2. size and shape
3. gram status (positive or negative)
4. presence of any chemical reactions
5. changes in color
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?
Answer: You would need to determine the motility before gram status. You can observe motility on a wet
mount and then heat fix your sample to gram stain your sample. If you were to
begin with using gram staining, you would kill your sample with heat fixing, you would not be able to observe any
motility.
4. A facultative anaerobe is a microorganism capable of growth under what
conditions?
Answer: aerobic and anaerobic conditions
5. As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why?
Answer: It would thrive because it does not bubble when it comes in contact. Streptococcus is gram negative,
anaerobic.
Catalase negative = no bubble formation Catalase
positive = bubble formation
6. Streptococcus is most often streaked onto
Answer: Blood agar
7. True or False. The Lancefield groups are used to subdivide antigenic groups
of gamma-hemolytic Streptococcus
Answer: False
Questions and Guide Answers
100% Verified Graded A+
1. The concept of treating all samples, whether known or unknown, as po-
tentially hazardous (or pathogenic) materials is known as
Answer: universal precautions
2. List at least 3 observations a researcher would be sure to note while assess-
ing an unknown microbial sample.
Answer: 1. any motility
2. size and shape
3. gram status (positive or negative)
4. presence of any chemical reactions
5. changes in color
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?
Answer: You would need to determine the motility before gram status. You can observe motility on a wet
mount and then heat fix your sample to gram stain your sample. If you were to
begin with using gram staining, you would kill your sample with heat fixing, you would not be able to observe any
motility.
4. A facultative anaerobe is a microorganism capable of growth under what
conditions?
Answer: aerobic and anaerobic conditions
5. As Streptococcus is catalase negative would it thrive or die in the presence of
peroxides? Why?
Answer: It would thrive because it does not bubble when it comes in contact. Streptococcus is gram negative,
anaerobic.
Catalase negative = no bubble formation Catalase
positive = bubble formation
6. Streptococcus is most often streaked onto
Answer: Blood agar
7. True or False. The Lancefield groups are used to subdivide antigenic groups
of gamma-hemolytic Streptococcus
Answer: False
