Page 70 - MNU microbiology theoritical 2025

General Microbiology & Immunology (PM 401) Second level Semester 4 2024/2025

• The generation time is measured during this period of active multiplication

Calculation of generation time

◼ Once we know there are n generations in t hours, we can find the growth rate

constant, K (number of generations per hour).

• K = n / t generations

• So generation time is equal to 1 / K hours, or 60 / K minutes

Exercise

Measure Culture at 9:00 a.m. 10,000 cells / ml

Measure Culture at 3:00 p.m. 100,000 cells / ml
Calculate n
n = 3.3 (logN t – logN o )

n = 3.3 (5- 4)

n = 3.33 Generations in 6 Hour
Therefore: Generation Time = 360 Minutes / 3.33 Generations

g = 108 Minutes to Generate

General Microbiology & Immunology (PM 401) theoretical handbook Page 59