University of Central Florida (UCF) MCB2004 Microbiology for Health Professionals Practice Exam 2

The stages of bacterial growth in a closed culture are accurately described by the lag, log, stationary, and death phases.

During the lag phase, bacteria adapt to their new environment. Although they are metabolically active, there is little to no increase in cell number as they prepare for subsequent growth.

The log phase, also known as the exponential phase, is characterized by rapid cell division and population growth. Bacteria multiply at a constant rate, and the population size doubles at regular intervals, representing the fastest growth period.

Following this, the stationary phase occurs when nutrient depletion or waste accumulation slows growth. The rate of cell division balances out with the rate of cell death, leading to a stable population level.

Finally, the death phase is marked by an increase in cell death as resources become increasingly scarce, leading to a decline in the overall population.

This sequence accurately captures how bacterial populations behave in a closed environment, reflecting their response to environmental factors and nutrient availability.