Reference no: EM131535002

1) Suppose your professor handed you a test tube with 4.o 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 and Show your calculations.

2) You were instructed to add 1.0 mL out of 5.0 mL of an undiluted sample to 99 mL of sterile diluent. Instead, you add all 5.0 mL to the 99 mL. What was the intended dilution and what was the actual dilution? Show your work.

3) The plate has 259 colonies, with a sample volume of 10^(-6) mL. What was the original concentration in the sample? How many colonies should be on the plate inoculated with a sample volume of 10^(-7) mL using the same sample?

4) A nutrient agar plate labeled 10^(-5) mL had 154 colonies after incubation. What was the cell density in the original sample?