Growth rate is the change per unit time. A. Growth frequently estimated by increase in cell counts. Doubling time can be calculated directly from graph. C. Generation time is time required for single cell to divide. Doubling time is same but usually refers to doubling of total population.
Generation time varies with species and conditions.
Speedy bacteria in liquid culture may have values ranging from 0.1-3 hr. 4. In soil, can be slower than in liquid. However, unrestricted growth does not occur in reality. A single bacterium growing under optimum conditions for 27 hours would produce a population that would cover the earth with a 6 ft thick layer. May require synthesis of enzymes or growth factors.