Bio 2010 - Microbiology » Fall 2021 » Streak For Isolation Technique

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Question #1
A student in our class makes their first Streak-for-Isolation plate and has it returned to them after incubation. Looking at it, you notice that there is bacterial growth in the first two quadrants/sectors, but not in the last two quadrants/sectors. Which of the following is the most likely explanation for this observation?
A.   they did not incubate the agar plate long enough
B.   they did not make contact in the second sector/quadrant while making the third sector/quadrant.
C.   they did not incubate the agar plate at the ideal temperature
D.   they forgot to flame their loop before making the next sector/quadrant
Question #2
Which of the following sectors/quadrants of our Streak-for-Isolation plate should have ISOLATED COLONIES growing in it?
A.   0
B.   I
C.   II
D.   III
Question #3
After making and incubating your Streak-for-Isolation plate a student notices that they have confluent growth in EVERY sector/quadrant. Which of the following most likely explains what happened?
A.   they returned the flame loop to the broth between every sector/quadrant
B.   the bacteria spread through each sector during incubation
C.   they left the top of the Petri open too long during making the streak
D.   the tryptic soy agar plate was contaminated prior to making the streak
Question #4
Which of the following would be considered a next step application for any isolated colonies on your streak-for-isolation plate?
A.   inoculation
B.   incubation
C.   more than one of the above is correct
D.   inspection
E.   identification
F.   none of the above is correct
Question #5
Which of the following observations would suggest that a plate was inoculated with a pure culture?
A.   isolated colonies are all white in color, but some colonies are noticeably larger than others.
B.   bacterial growth is apparent in all four quadrants.
C.   bacterial growth is apparent along the streaks connecting each quadrant.
D.   isolated colonies have uniform color and same size.

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