Question

Identify the correct sequence of microbial growth curve: A. Stationary phase, B. Lag phase, C. Death phase, D. Log phase.

• A. B, A, D, C
• B. A, B, D, C
• C. B, D, A, C
• D. A, D, B, C

Hint:

Microbial growth curve sequence is: Lag phase \(\rightarrow\) Log phase \(\rightarrow\) Stationary phase \(\rightarrow\) Death phase.

Answer 1

The Correct Option is C

Concept:
A microbial growth curve shows the growth pattern of microorganisms in a closed culture system. It has four major phases.

Step 1: Lag phase.
In the lag phase, microorganisms adapt to the new environment. Cell division is slow or absent. \[ \text{First phase} = B \]

Step 2: Log phase.
In the log phase, microorganisms divide rapidly and the population increases exponentially. \[ \text{Second phase} = D \]

Step 3: Stationary phase.
In the stationary phase, the rate of cell division becomes equal to the rate of cell death. Nutrients become limited. \[ \text{Third phase} = A \]

Step 4: Death phase.
In the death phase, cells die due to nutrient depletion and accumulation of toxic products. \[ \text{Fourth phase} = C \] Therefore, the correct order is: \[ B, D, A, C \] \[ \therefore \text{Correct Answer is (C)} \]