all details about the growth of bacteria and factors which helps in growth autotrophs,heterotrophs,generation time, bacterial count, bacterial growth curve, batch culture and continuous culture

1. GROWTH OF BACTERIA
INTRDUCTION:-
The minimum nutritional requirement for growth and multiplication of bacteria includes sources of carbon,
nitrogen , hydrogen, oxygen and some inorganic salts
Bacteria can be classified on the basis of nutrition as follows:-
1. Autotrophs:-
Bacteria which can synthesise their essential metabolites.
Autotrophs obtain their energy either pohotosynthetically (photolithotrophsor photoautotrophs) or by
oxidation of chemical compounds (chemolithotrophs or chemoautotrophs).
2. Heterotrophs :-
These bacteria are unable to synthesise their own metabolites.
They depend on preformed organic compou n d s. Majority of the pathogenic bacteria are heterotrophs and
parasitic.
BACTERIAL GROWTH:-
A. Bacterial Cell Division
B. Generation Time:-
The time required for a bacterium to give rise to two daughter cells under optimum conditions, is known as
the generation time.
The generation time in most of the medically important bacteria is about 20 minutes.

2. In Mycobacteriumtuberculosis it is about 20 hours and in lepra bacilli it is 20 days.
C. BacterialCount:-
1. Total count: This indicates total number of bacteria in the specimen, irrespective of whether they are living
or dead
2. Viable count: It measures the number of living (viable) cells.
Viable counts are obtained by dilution or plating methods.
D. Bacterial Growth Curve
When a bacterium is inoculated into a suitable culture liquid medium and incubated, its growth follows a
definite course.
E. BatchCulture and Continuous Culture:-
When bacteria are grown in a vessel of liquid medium (batch culture)
the use of special continuous culture of bacteria is maintained by the techniques namely chemostat and
turbidostat are used.
F. Bacterial Growth in Vivo:-
There is a significant difference of bacterial growth in human body and artificial culture medium.
When bacteria multiply in host tissues, the situation may be intermediate between a batch culture and a
continuous culture.
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DHANANJAY SINGH