Question

You have a bacterial culture solution. When you directly measured the OD600, of the culture solution, it was 3. Then, you performed a 10-fold dilution and measured the OD600

of the diluted solution, which was 0.5. Thirdly, you performed another 10-fold dilution and measured the OD600 of the diluted solution, which was 0.07. Assuming that OD

600 =1 is equivalent to 10^9 cells/ml, how many cells do you have in 1ml of the original culture?

You have a bacterial culture solution. When you directly measured the OD6o0, of the culture solution, it was 3. Then, you performed a 10-fold dilution and measured the OD6o0 of the diluted solution, which was 0.5. Thirdly, you performed another 10-fold dilution and measured the OD600 of the diluted solution, which was 0.07. Assuming that OD6o0-1 is equivalent to 109 cells/ml, how many cells do you have in 1 ml of the original culture? A) 3 x 109 cells B) 6 x 10 cells C) 7 x 109 cells D) 8x 109 cells E)3 x 1010 cells

Answer 1

The answer is C

It has 7 ×10⁹ cells per ml. The dilution of sample for OD measurement gives correct idea of OD value of solution. If the OD is more than one we must dilute the solution.