Question

3. Suppose there are 5 x 106 E. coli cells in a transformation reaction and you plate them all out to plates containing ampicillin. After incubating the plate at 37 deg C for 18 hours you observe 500 colonies. What fraction of the cells were transformed in this experiment

Answer 1

Answer:

1/10^4

Explanation:

Given that 500 colonies were observed on ampicillin plate after transformation. 1 colony represents 1 transformed bacteria because each colony is assumed to have grown from one single bacteria. Hence, 500 bacteria had transformed from 5*10^6 bacteria.

Fraction of cells that got transformed = (Number of cells that were transformed/ Number of total cells)

= 500/(5*10^6)

= 1/10^4

Hence, 1/10^4 cells were transformed in experiment.