Starting from a single individual, what is the size of a population of bacteria at the end of a 2-hour time period if they reproduce by binary fission every 20 minutes? (Assume unlimited resources and no mortality.)
A) 16
B) 32
C) 64
D) 128

Question

Quizplus · Accepted Answer

In a 2-hour time period, there are 6 cycles of binary fission (2 hours = 120 minutes / 20 minutes per cycle = 6 cycles). During every cycle, the population doubles, so the formula for the final population size would be: starting population x 2^(number of cycles). 
Starting with just one individual, after 6 cycles, the population would be: 1 x 2^6 = 64. Therefore, the correct answer is option C) 64.

Starting from a Single Individual, What Is the Size of a Population