Starting with four bacterial cellsml in a rich nutrient medi

Starting with four bacterial cells/ml in a rich nutrient medium, with a 1-hour lag phase and a 20- min generation time, how many cells will there be in 1 liter of this culture after 1 hour? 2 hours?

Solution

N = N₀ 2ⁿ ;

N = population after t hours

N₀ = Initial population = 4 cells/ml

n = t/g

g = generation time = 20 minutes

n at 1 hour is = 60 minutes/ 20 minutes = 3

Population size after 1 hour is, N (1h) = 4* 2^3 = 32 cells/ml or 32* 10^3 cells/Lit

After 2 hours, the population is,

N at 2 hours is = 120 minutes/ 20 minutes = 6

N (2h) = 4* 2^6 = 256 cells/ml or 256* 10^3 cells/ml