Question

One cell with generation times of 60 minutes are inoculated into a culture medium. How many cells are there after 5 hours? (Assuming all cells divide by binary fission in log phase and remained viable).

a) 32
b) 160
c) 180
d) 96

Answer 1

Using the exponential growth formula N₁ = No × 2ⁿ for one cell dividing every 60 minutes, after 5 generations (5 hours) the total number of cells would be 32.

Step-by-step explanation:

To calculate how many cells there will be after 5 hours when one cell with generation times of 60 minutes is inoculated into a culture medium, we use the formula for exponential growth by binary fission: N₁ = No × 2ⁿ, where No is the initial number of cells and n is the number of generations. Since the generation time is 60 minutes, and there are 5 hours (i.e., 300 minutes) in the period we are considering, there would be 300 minutes / 60 minutes per generation = 5 generations. Therefore, if we start with one cell, the number of cells after 5 generations would be 1 × 2⁵, which is equal to 32.

Therefore, the correct answer is: a) 32.