Question

Which phase of microbial growth is characterized by a balance between cell division and cell death?

• A. Lag phase
• B. Exponential phase
• C. Stationary phase
• D. Death phase

Hint:

• Lag phase Adaptation, no significant growth.
• Exponential (log) phase Maximum, constant growth rate.
• Stationary phase Net growth is zero (division rate = death rate or division stops). Caused by nutrient depletion or waste accumulation.
• Death phase Death rate>division rate. Viable cell count declines.

Answer 1

The Correct Option is C

In microbiology, the growth of microbial cells in a culture medium can be divided into distinct phases. Each phase represents a different stage of population dynamics:

• Lag phase: This initial phase is characterized by cellular adaptation to the new environment. Cells are metabolically active but not yet dividing rapidly.
• Exponential phase: Also known as the log phase, this is where cells divide at a constant and rapid rate, resulting in exponential population growth.
• Stationary phase: During this phase, the rate of cell growth equals the rate of cell death. Nutrient depletion and waste accumulation start limiting further growth, thus establishing a dynamic equilibrium.
• Death phase: Cell death exceeds cell division due to prolonged nutrient depletion and accumulation of toxic byproducts.

Therefore, the phase of microbial growth characterized by a balance between cell division and cell death is the Stationary phase.