Describe the bacterial growth curve and its phases.

The bacterial growth curve shows cell population changes over time in batch culture. The lag phase is an adaptation period where cells synthesize enzymes and adjust to the medium; no net increase in cell number occurs. The exponential (log) phase shows constant, maximal growth rate with unlimited nutrients. The stationary phase occurs when growth rate equals death rate due to nutrient depletion and waste accumulation; total cell number remains constant. The death phase shows declining viable cell counts as cells die from nutrient starvation and toxic metabolites. Understanding these phases is essential for optimizing fermentation timing and harvest.