Serial Dilutions Essay Example

is to verify the accuracy of this culture's concentration. To do so, you would create dilutions using test tubes with different concentrations of bacterial samples and place one sample from each tube onto a petri dish. This process involves diluting the large amount of bacteria into various concentrations, where a dilution rate of 200 X 10^-6 will result in 2x 10^8 cfu/ml.

To determine the concentration of the culture, begin by adding 1.0 ml of the culture to a test tube and shaking it. Create a range of dilutions from 10^2 to 10^8 by transferring 1.0 ml of the previous dilution to each subsequent test tube and shaking them. After shaking the test tube with a 10^8 dilution, transfer 1.0 ml to a test tube with a 10^6 dilution using a pipet. Shake the test tube with a 10^6 dilution and transfer 1.0 ml to the test tube with a 10^4 dilution. Shake the test tube with a 10^4 dilution and transfer 1.0 ml to the test tube with a 10^2 dilution, using a pipet.

Next, shake the test tubes as follows:
- With a starting concentration of 10⁸, transfer 1.0 ml to one petri dish and 0.1 ml to another petri dish using;a new pipet.
- With;a starting concentration of 10⁶, repeat this process for petri dishes.;
- With;a starting concentration of [STARTING CONCENTRATION], repeat this process for;[PETRI DISHES].

Mix agar with the contents of each petri dish, allowing it time to cool and harden.Once hardened, count plates containing between25-250 colonies.This method is usedto verifythe accuracyofthe culture'sconcentration.

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