Suppose your professor handed you a test tube with 20 mL of

Suppose your professor handed you a test tube with 2.0 mL of an E. coli broth culture in it and told you to make a 10^-1 dilution of the entire culture. Explain how you would do this. Show your calculations. Suppose your professor handed you a test tube with 2.0 mL of an E. coli broth culture in it and told you to make a 10-^-2 dilution of the entire culture. Explain how you would do this. Show your calculations.

Solution

1. 10 Fold dilutions: Take a test tube and dilute the 2.0 ml bacterial culture with 18.0 ml sterile broth culture to give a total of 20 ml. 2.0/20ml= 10 . Hence, 10 fold dilution.

2. Take a test tube A and fill it with 9 ml of distilled water, then take 1 ml from E.Coli broth and put it in the test tube A and mix it. This is 10^-1 dilution. Next, take a test tube B and fill it with 9 ml of distilled water , take 1 ml from test tube A and put it in test tube B, mix it. This is 10^-2 dilution.