1.7. BACTERIAL GROWTH It is an orderly increase in all the components of an organism. It is an increment in biomass. It is synchronous with bacterial cell reproduction.
Generation time It is the time taken for the size of a bacterial population to double. Bacteria grow by taking nutrients and incorporate them into cellular components; then bacteria divide into two equal daughter cells and double the number.
Bacterial growth phases
The pattern in cell numbers exhibited by bacterial population obtained after inoculation Of a bacterium into a new culture medium. The normal bacterial growth curve has four phases.
1. Lag phase The period of adaptation with active macro molecular synthesis like DNA, RNA, various enzymes and other structural components. It is the preparation time for reproduction; no increase in cell number.
2. Exponential(log) phase The period of active multiplication of cells. Cell division precedes at a logarithmic rate, and determined by the medium and condition of the culture.