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    Dilution Series

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    You performed the following dilution series on a culture of Escherichia coli:

    1 ml of the original culture to 99 ml broth
    then 1 ml cell suspension to 9 ml broth
    then 2 ml to 8 ml broth
    then 0.1 ml to a culture plate

    The next day, you count 52 colonies on the plate. What was the concentration of the original culture? (Hint: Drawing the dilution series may help.)

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    https://brainmass.com/biology/prokaryotic-cells/working-serial-dilutions-3948

    Solution Preview

    Whenever you get a wordy dilution problem like this one, it helps to draw out the dilution series so you can better visualize what is going on.

    1 ml of the original culture to 99 ml broth
    -- This is a 1:100 dilution
    (1 ml is being added to 100 ml total, where total = amount added + amount already in the flask)

    then 1 ml cell suspension to 9 ml ...

    Solution Summary

    The expert examines working with serial dilutions.

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