Question 1: You have already determined the doubling time of 24 min for a certain E. coli strain. You also determined the cell density of 107 cells/mL by plate counting. You diluted the cell to 1:100, inoculated 0.1 mL of the diluted cells into 9.9 mL of the same medium, and incubated under the same growth condition that was used to determine the doubling time and cell density. How long should you incubate to reach a cell density of 32,000 cells/mL?

Question 2: Let's say the A600 of the 5 mL overnight culture at 10:00 AM is 1.0 and you want to harvest 10 mL culture of E. coli cells at A600 = 0.8 at 2:00 PM on the same day. You know E. coli doubles every 30 min under the growth conditions used. How much volume of the 5 mL culture would you need to inoculate into a fresh 10 mL medium? Assume that only 50% of cells in 5 mL overnight culture is alive.

Question 3: Calculate the theoretical total DNA yield in (µg) and DNA concentration (ng/µL) assuming that you recover 100% of the pure E. coli genomic DNA (4.6 x 106 bp) in 0.1 mL of final DNA sample from a 2-mL overnight culture of 2 X 109 cells/mL. MW of DNA base pair is 660 g/mole.