Starting from a single individual, what is the size of a population of bacteria that reproduce by binary fission every 20 minutes at the end of a 2-hour time period? (Assume unlimited resources and no mortality.)

A) 6

B) 18

C) 128

D) 512

E) 1,024

C) 128

Explanation:

In binary fission each bacterial cell will divide into two parts.

1. Since the bacteria divides divides after every 20 min, We have to find the number of division in two hours two hour (2x60=120 min) which will be;

120:20=6

It will undergo 6 divisions.

2. To calculate the number of bacteria at the end of 2 hours

Bacteria in the beginning x 2∧ Number of division

1 * 2∧6 = 128 Bacteria