In: Civil Engineering
Briefly explain the general growth pattern of bacteria indicating the names of phases.
Bacterial growth is an increment of number of bacteria in population rather than size of individual cells. Bacteria generally shows exponential or geometrical growth rate as they generate by cell binary division. One cell breaks into 2, 2 goes breakdown into 4, 4 into 16 and so on. The gereration time generally varies for different bacteria and environmental conditions. In controlled lab environment, bacteria grows on agar dishes for ease of observation.
The different phases of bacterial growth are-
1. Lag phase- In this phase bacteria adapt to new environment and no division of cell occurs. The cell will grow in mass, volume, RNA and metabolic activity etc.
2. Exponential phase- In presence of adequate medium and nutrients, bacteria starts cell division. The growth is generally shown by geometric progression. The rate of logarithmic growth of bacteria is expressed as generation time(G).
G = t/n
Where, t= time and n= number of generation
3. Stationary phase- After a certain time, bacterial counts are too high but nutrients are less so rate of generation of cell will be nearly equal to death rate of cells.
4. Death phase- In this phase bacterial cells decreases geometrically. This may be caused by nutrients lack, temperature effect and many more.