In which phase of the bacterial growth curve would you expect to observe the highest number of endospores in a Bacillus cell culture?

• A. Lag phase
• B. Death phase
• C. Log (exponential) phase
• D. Stationary phase

Answer: (D)

Verified step by step guidance

1. Understand the bacterial growth curve phases: Lag phase (adaptation), Log phase (rapid growth), Stationary phase (growth rate equals death rate), and Death phase (decline in viable cells).
2. Recall that endospore formation is a survival mechanism triggered by nutrient limitation or stressful conditions, which typically occur when growth slows down.
3. Identify that during the Lag phase, cells are metabolically active but not dividing rapidly, so endospore formation is minimal.
4. Recognize that in the Log phase, cells are actively dividing and conditions are favorable, so endospore formation is unlikely.
5. Conclude that the Stationary phase, where nutrients are depleted and waste accumulates, provides the environmental stress that induces Bacillus cells to form the highest number of endospores.