BIOD 171 Essential Microbiology Portage Learning Module 5 Exam Questions and Answers\

BIOD 171

M5: Module 5 Exam - Requires Respondus

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Question 1

Not yet graded / 3 pts

The concept of treating all samples, whether known or unknown, as potentially

hazardous (or pathogenic) materials is known as __________.

Your Answer:

universal precautions

Universal precautions

Question 2

Not yet graded / 3 pts

List at least 3 observations a researcher would be sure to note while assessing an

unknown microbial sample.

Your Answer:

size and shape, motility, chemical reactions, gram stain, color change

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

Question 3

Not yet graded / 10 pts

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?

Your Answer:

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The motility should be determined first. Observing motility requires a wet mount. Gram

staining requires heat fixation. Heat fixing would kill the organism and motility would

not be observable.

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 same liquid

culture can be heat fixed and Gram stained.

Question 4

Not yet graded / 3 pts

A facultative anaerobe is a microorganism capable of growth under what conditions?

Your Answer:

A facultative anaerobe is capable of growth under aerobic and anaerobic conditions.

A facultative anaerobe is capable of growth under aerobic (with oxygen) and anaerobic

(without oxygen) conditions.

Question 5

Not yet graded / 10 pts

As Streptococcus is catalase negative would it thrive or die in the presence of peroxides?

Why?

Your Answer:

Streptococcus would die in the presence of peroxides because it is not able to break

down the peroxides.

Streptococcus would not survive in the presence of peroxides—it is unable to

breakdown peroxides (catalase negative). Left unchecked, peroxides would damage the

cellular integrity of Strep causing lysis/cell death.

Question 6

2 / 2 pts

Streptococcus is most often streaked onto:

Spirit Blue agar

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