2. The bacterial growth curve represents the number of live
cells in a bacterial population over a period of time.
BACTERIAL GROWTH CURVE
Lag Log Stationary Death
phase phase phase phase
What Is Growth Curve ?
3.
4. Bacteria adapt themselves to growth conditions. It is
the period where the individual bacteria are
maturing and not yet able to divide. During the lag
phase of the bacterial growth cycle, synthesis of
RNA, enzymes and other molecules occurs.
Length of this phase depends on type of bacterial
species,culture medium and environmental factors.
LAG PHASE (1-4 HOUR)
5. It is a growth period of a cluster of cells in a
culture medium. During this phase, there is an
exponential increase in the number indicated by
a section of the growth curve. This section is a
straight line segment when the logarithm of
numbers is plotted against time.
Exponential growth cannot be continue
indefinitely, however, because the medium is
soon deplated of nutrients and enriched with
wastes.
LOG PHASE (EV: 8 HOURS)
6. Stationary phase is the stage when growth ceases but
cells remain metabolically active. Several physical and
molecular changes take place during this stage that
makes them interesting to explore. The characteristic
proteins synthesized in the stationary phase are
indispensable as they confer viability to the bacteria
Death of cells as a function of time is rather
unpredictable and very difficult to explain.
STATIONERY PHASE(FEW HOURS TO
DAYS)
7. Bacteria run out of nutrients and die although
number of cells remain constant.
The death phase is brought by exhausted of
nutrients, accumulation of toxic products and
autolytic enzymes.
DEATH PHASE
8. I Would like to express my special thanks of gratitude to
our Microbiology professor Dr. Samrat Paul sir who gave
me the golden opportunity to make this wonderful
presentation on bacterial growth curve which also helped
me in doing a lot of research and I come to know about so
many new things. I new really thankful to my teacher.
ACKNOWLEDGEMENT
