Which stage of the bacterial growth curve is characterized by active cell division?

The stage of the bacterial growth curve characterized by active cell division is the log phase. During this phase, bacteria undergo rapid binary fission, leading to exponential growth. The nutrients are plentiful, and environmental conditions are favorable, allowing for high metabolic activity. As a result, the number of viable cells increases dramatically in a short period.

In contrast, the lag phase is where bacteria adapt to their new environment and prepare for division, but no significant increase in cell number occurs yet. The stationary phase represents a period where growth levels off as the number of new cells equals the number of dying cells, typically due to nutrient depletion or accumulation of waste products. The death phase occurs when the number of dying cells exceeds the number of new cells being formed, leading to a decline in the overall population. Thus, the log phase is specifically the period of maximum growth and active cell division, distinguishing it from all other phases.