Tuesday, 14 February 2017

Bacterial growth curve

·         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.
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
N= 6 =26 = 2 X2 X 2X 2X 2X 2 = 64
= 64 X 100= 6400 cells

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