Question

If one starts with 10,000 (10^4) cells in a culture that has a generation time of 2 h, how many cells will be in the culture after 4 and 48 h?

(a) 4.0×10^4 cells, 1.7×10^11 cells

(b) 4.2×10^4 cells, 1.1×10^11 cells

(c) 4.6×10^4 cells, 1.5×10^11 cells

(d) 4.8×10^4 cells, 1.3×10^11 cells

The question was asked in unit test.

Asked question is from Continuous Culture topic in division Microbial Growth Kinetics of Bioprocess Engineering

Answer 1

Right choice is (a) 4.0×10^4 cells, 1.7×10^11 cells

The best explanation: Use the equation X= 2^n X0, where X0 is the initial number of cells, n is the number of generations, and X is the number of cells after n generations.

After 4 h, n=4 h/2 h per generation= 2 generations:

X=2^2 (10^4) = 4.0×10^4 cells

After 48 h, n= 24 generations:

X = 2^24 (10^4) = 1.7×10^11 cells

This represents an increase of less than one order of magnitude for the 4-h culture, and seven orders of magnitude for the 48-h culture.