Determine the number of colonies counted on the LB plate in the following transformation experiment.

Question

The amount of plasmid on the plate being counted was 0.04 micrograms.
The transformation efficiency was calculated to be 4 x 10^3.

Answer 1

Transformation efficiency = (Total number of cells growing on the agar plate) / (Amount of DNA spread on the agar plate (in µg)).

So if the transformation efficiency is 4 x 10^3 and the amount of plasmid on the plate is 0.04 micrograms, then:

4 x 10^3 = x / 0.04 micrograms, so x = 160 colonies.