1
Growth curve
of Bacteria
, 2
Growth is the orderly increase in the sum of all components of an
organism. Multiplication of cell is a consequence of growth.
Multiplication of a bacterium into two daughter cells occurs by a process
called binary fission. The resulting daughter cells are genetically identical
to the original cell.
, 3
This doubling time is 20-22 minutes for ordinary bacteria, 18-24
hr for M.tuberculosis and 36 hours for M.leprae.
The growth of bacteria in fluid media occurs in various phases
producing a curve called growth curve.
, 4
Growth curve
If bacteria are grown in a fluid media and log of
bacterial count is plotted on ordinate and time against
abscissa, a curve is produced which is called growth
curve.
4 phases
, Growth Curve
Two types growth curve can be drawn according to
the measurement of the cell number
Total count •Based on the “number of cells present”,
irrespective of whether “living or dead”
•An organism is considered living or viable if it is
capable of continued multiplication
Viable count •Measures only those cells capable of
growing and hence of producing a
colony on a suitable growth media
, 6
Phases
4 phases
Lag phase
Log / logarithmic /
Exponential phase
Stationary phase
Decline phase
, Growth curve 7
File:Bacterial growth en.svg
Growth curve
of Bacteria
, 2
Growth is the orderly increase in the sum of all components of an
organism. Multiplication of cell is a consequence of growth.
Multiplication of a bacterium into two daughter cells occurs by a process
called binary fission. The resulting daughter cells are genetically identical
to the original cell.
, 3
This doubling time is 20-22 minutes for ordinary bacteria, 18-24
hr for M.tuberculosis and 36 hours for M.leprae.
The growth of bacteria in fluid media occurs in various phases
producing a curve called growth curve.
, 4
Growth curve
If bacteria are grown in a fluid media and log of
bacterial count is plotted on ordinate and time against
abscissa, a curve is produced which is called growth
curve.
4 phases
, Growth Curve
Two types growth curve can be drawn according to
the measurement of the cell number
Total count •Based on the “number of cells present”,
irrespective of whether “living or dead”
•An organism is considered living or viable if it is
capable of continued multiplication
Viable count •Measures only those cells capable of
growing and hence of producing a
colony on a suitable growth media
, 6
Phases
4 phases
Lag phase
Log / logarithmic /
Exponential phase
Stationary phase
Decline phase
, Growth curve 7
File:Bacterial growth en.svg
