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14 Cards in this Set
- Front
- Back
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Serial Dilution |
Method of reducing the amount of bacteria in a particular medium by transferring bacteria from 1 tube into another tube Dilutes the quantity of bacteria from the original tube |
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Why is serial dilution performed? |
1. To isolate individual colonies 2. To quantify the bacteria in order to estimate the amount in the original colony |
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Countable plate |
An agar plate that contains between 30 and 300 colonies of bacteria |
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Categories of non countable plates |
1. No Growth (NG) 2. Too Few to Count (TFTC) 3. Too Numerous to Count (TNTC) |
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NG |
No Growth 0 colonies per plate |
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TFTC |
Too Few to Count Less than 30 colonies per plate |
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TNTC |
Too Numerous to Count More than 300 colonies per plate |
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What machine can be used to accurately view the exact number of colonies on a plate? |
Quebec Colony Counter |
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How should one count bacterial colonies on a Quebec colony counter? |
- snake back and forth in rows - count only the bacteria in the box, on the top line, and on the front/preceding line |
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CFU |
Colony Forming Units |
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Formula for Dilution Factor |
(Amount added / [amount added + diluent in tube]) • previous tube's dilution factor) |
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Ten Fold Dilution |
Dilution factor increases by a factor of 10 each time |
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Formula for finding the original concentration |
# of colonies • inverse of dilution factor |
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How is the concentration of a sample correctly written? |
____ CFU/mL |
