The Log Phase is defined as which?

• A. The period of exponential growth of bacterial population.
• B. A plateau in growth
• C. A period of cell death
• D. No growth due to depletion

Answer: (A)

The log phase is the exponential growth phase of a bacterial population, where cells reproduce at a constant rate and the number of cells doubles at regular intervals. This occurs when nutrients are plentiful and waste hasn’t reached inhibitory levels, so the growth rate is at its maximum and net population increase is truly exponential. On growth curves, this phase appears as a straight line on a semilog plot because the log of the population size rises linearly with time. This stage is especially useful for determining generation time and studying rapid growth dynamics. The other descriptions refer to phases where growth slows or stops: a plateau (stationary phase) means births balance deaths, a period of cell death is the death phase, and no growth due to depletion points to resource exhaustion, not the rapid exponential rise seen in the log phase.