In a plaque assay, a microbiologist counts 20 plaques on a plate. How many plaque-forming units can be assumed to have been present in the original bacterium-virus mixture on the plate, if there was no dilution of the mixture prior to plating? 2 10 20 40 Solution 2^number of generations * initial number of bacteria = total no. of bacteria present after n generations. assuming no. of generations is 1(not specified in the question), 21 * y =20 2y=20 y=20/2=10 so, the initial count must be 10..

1. In a plaque assay, a microbiologist counts 20 plaques on a plate. How many plaque-forming
units can be assumed to have been present in the original bacterium-virus mixture on the plate, if
there was no dilution of the mixture prior to plating?
2
10
20
40
Solution
2^number of generations * initial number of bacteria = total no. of bacteria present after n
generations.
assuming no. of generations is 1(not specified in the question),
21 * y =20
2y=20
y=20/2=10
so, the initial count must be 10.