The growth of bacterial cultures in a closed system is best described as:

• A. A constant population size from the beginning
• B. A series of phases including lag, log, stationary, and death
• C. A continuous exponential increase without any decline
• D. A random fluctuation in cell numbers with no discernible pattern

Answer: (B)

Verified step by step guidance

1. Understand that bacterial growth in a closed system (like a batch culture) does not remain constant or increase indefinitely due to limited nutrients and accumulation of waste products.
2. Recall the typical phases of bacterial growth: lag phase (adaptation period with little to no cell division), log phase (exponential growth where cells divide at a constant rate), stationary phase (growth rate slows as resources deplete and waste accumulates, leading to a balance between cell division and death), and death phase (decline in viable cell numbers as conditions become unfavorable).
3. Recognize that the growth curve is characterized by these distinct phases rather than a constant population size, continuous exponential growth, or random fluctuations.
4. Identify that the correct description of bacterial growth in a closed system is a series of phases including lag, log, stationary, and death phases.
5. Summarize that this pattern reflects the dynamic changes in bacterial population over time due to environmental constraints in a closed system.