Question

Examine the image below, and pay special attention to the phase circled and indicated by the black arrow. In 2-3 sentences, identify the circled phase and explain why this phase is necessary for the remainder of the cycle to occur correctly.

Answer 1

That circled phase is the lag phase of the bacterial growth curve. During lag bacteria are not dividing but are metabolically active—repairing damage, synthesising enzymes and macromolecules, and adjusting gene expression so they can take up nutrients and enter the exponential (log) phase; without this preparatory period the population could not mount the coordinated high-rate growth seen in the remainder of the cycle.