BIOD 171

L9: Lab Exam 9

Question 1

Not yet graded / 6 pts

Using the observations made and recorded from PL09 Unknown Pathogen, complete the

results sections accordingly.

Given Culture A and Culture B were accidentally mixed, what observations were made

from the Gram stain (shown below)?

Your Answer:

Purple: Gram-Positive, coccus, clusters

Pink-: Gram-Negative, Bacillus

Gram-positive cocci (spherical) clusters and Gram-negative bacillus (rods) were

observed.

Question 2

Not yet graded / 6 pts

Using the observations made and recorded from PL09 Unknown Pathogen, complete the

results sections accordingly.

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The hemolytic properties of both cultures were next examined by streaking each culture

on a blood agar plate (shown below). What is the hemolytic status of Culture A? Culture

B?

Your Answer:

Culture A: Beta Hemolysis (clear margins around colonies/yellowish)

Culture B: Gamma Hemolysis (colonies growing but no color change in the medium)

Culture A exhibits beta hemolysis as defined by the region of clearing around the

growing bacterial streak.

Culture B exhibits gamma-hemolysis (non-hemolytic) as indicated by the white colonies

growing on the still red agar.

Question 3

Not yet graded / 6 pts

Using the observations made and recorded from PL09 Unknown Pathogen, complete the

results sections accordingly.

Given the results from a MacConkey agar plate shown below, what is the shape of

Culture A? Culture B?

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