Bacterial Growth Curve
If a group of scientist were preparing to perform an experiment to characterize a bacterium's ability to utilize maltose as a sugar source, during which phase of the growth curve would it be best to sample the bacteria for your experiment? Why?
Bacterial growth can be divided into 4 phases, Lag phase, Log phase, Stationary phase and Death phase. Adaptation of bacteria to the environment mainly happens during the Lag phase. Bacteria start utilizing available nutrients and multiple in Log phase. In this case, the ability of Maltose utilization of a strain of bacteria could be done determined in the log phase. Sampling in log phase has its own advantages. Firstly, the number of bacteria utilizing Maltose as a carbon source would be substantially higher. The multiplication of such bacteria is only possible, when there is a sufficient amount of nutrient (in this case Maltose). Exponential or log phase is considered to be a doubling phase with extensive utilization of nutrients. Hence determination of bacteria in carbon source (Maltose) consumption is most ideal during the Log or Exponential phase.
Scientists have discovered a new strain of bacteria, Taracus henningcillum, and you would like to determine if this bacteria produces enough of the same enzymes required for cell division as other bacteria. What would be the best phase of the growth curve in which to study this question? Why?
As mentioned earlier, bacterial growth is observed to be highest in log phase. However, synthesis of enzymes and RNA molecules is done prior to cell multiplication. The new strain Taracus henningcillum would synthesize enzymes and RNA during Lag phase. This is not done during log phase, since log phase consist of cell replication and nutrient utilization. Lag phase consist of enzyme preparation, that would be used for cell multiplication and nutrient utilization. Hence, Taracus henningcillum can be sampled to check enzymes production for cell division during the log phase. Another reason for sampling of bacteria during lag phase is that bacteria learn to adapt in an environment during lag phase. During this period, they begin synthesis of enzymes and molecules for cell multiplication. Bacterial growth curve serves as an important tool in the determination of bacterial enzyme production, multiplication and nutrient utilization.
