·
Bacterial Generation Time (or) Doubling Time
1. Lag Phase
2. Exponential (or) logarithomic Phase (or) Log phase
3. Stationary phase
4. Decline Phase
1. Lag Phase:
·
When microorganism is introduced in to the first
medium.
·
It take some time to adjust which the new
environment.
·
Cellular metabolism is accelerated.
·
Cells are increasing in size.
·
By bacteria replicate.
2. Exponential (or) Log phase:
·
The microorganism rapidly growing and divided
state.
·
Organism DNA replicate begin by Binary fission
at a constant rate.
·
The time taken bacteria to double in number a
specified period is Known as the generation
time.
3. Stationary phase:
·
As bacteria Population continuous to growth .
·
All the nutrients in the growth medium are used
up by the microorganism for the Rapid multiplication.
·
Then reproduction rate will slow down.
·
This phase divided cells and number of cell
death rate is equal.
·
Finally stop the division completely.
4. Decline (or) Death Phase:
·
The bacteria completely loses its ability to
reproduce.
Ex:
E.coli ---------------------- 20 minutes
S.enterica --------------20 minutes
S.aureus -------------------30 Minutes
B.Cerus----------------------30 Minutes
Formula: 2 Number of
Generation X Intial Number of Bacteria = Total Cells
Ex :
“Bacillus subtilies “ Divided every 30 minutes, you inoculated a culture with exactly 100
Bacterial cells. After 3 hours, how many bacteria are present?
3 hours, B.subtilies Cells will Divided 6 times
Therefore,
N= 6 =26 = 2 X2 X 2X 2X 2X 2 = 64
= 64 X 100= 6400 cells
