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