Choose the correct sequence of stages of growth curve for bacteria [2002] a. Lag, log, stationary, decline phase b. Lag, log, stationary phase c. Stationary, lag, log, decline phase d. Decline, lag, log phase
Option A. 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.
