Lag phase of bacterial growth is described as which?

• A. Period of exponential growth
• B. Period when bacteria becomes accustomed to their environment. Not many bacteria, at this time
• C. Period of rapid cell division
• D. A period of net population decline

Answer: (B)

Lag phase is the adaptation period after bacteria are placed in a new environment. During this time, cells sense nutrients, adjust their metabolism, and synthesize the enzymes needed to utilize available substrates. Even though the cells are metabolically active, they don’t divide rapidly, so the population size doesn’t increase much. The description that fits this phase is the one that says bacteria become accustomed to their environment and that not many bacteria are present at this time. After lag, cells enter the exponential (log) phase, where rapid division occurs, and later phases include stationary and death as nutrients run out and waste accumulates.