Question

Choose the correct sequence of stages of growth curve for Bacteria.

• A. Lag, Log, Stationary, Decline phase
• B. Lag, Log, Stationary phase
• C. Stationary, Lag, Log, Decline phase
• D. Decline, Lag, Log phase

Answer 1

The correct option is A Lag, Log, Stationary, Decline phase

Four characteristic phases of the growth cycle are:

1. Lag phase- immediately after inoculation of the cells into fresh medium, where the synthesis of enzymes, proteins, RNA takes place.

2. Exponential (log) phase- where all the cells are dividing regularly by binary fission and are growing by geometric progression. The cells divide at a constant rate depending upon the composition of the growth medium and the conditions of incubation.

3. Stationary phase- exponential growth cannot be continued forever in a culture. Population growth is limited by one of three factors: exhaustion of available nutrients; accumulation of inhibitory metabolites or end products; exhaustion of space, (called a lack of biological space).

4. Death phase- if incubation continues after the population reaches stationary phase, a death phase follows, in which the viable cell population declines.