Question

After a period of rapid growth (log phase), bacterial growth rates will slow and enter the stationary phase. The number of viable cells no longer increases, but instead stays constant. In this activity you will indicate the statements that correctly describe what is happening during stationary phase. Select each statement that accurately describes what is happening to bacterial cultures during stationary phase. Select each statement that accurately describes what is happening to bacterial cultures during stationary phase. Harmful waste products may be accumulating. Cells are not increasing in number because they have not yet adjusted to the nutrient availability in the new media. The cells are dead; therefore, the number is staying constant. The number of cells that are dying is balanced by the number of new cells that are being formed. The cells are likely running out of nutrients.

Answer 1

The correct answers are:

The number of cells that are dying is balanced by the number of new cells that are being formed.

The cells are likely running out of nutrients.

The phases of bacterial growth are:

1. Lag phase is a phase during which bacteria adapt to new conditions, maturate and prepare for the division. Preparation includes synthesis of RNA, enzymes and other molecules. It lasts for few days.

2. Log phase is a phase in which bacteria divide. The growth is exponential, meaning that the cell number is constantly doubling (growth is at constant rate). Growth continues until the medium becomes depleted of nutrients and enriched with wastes.

3. Stationary phase is the phase in which growth rate of bacteria is equal to death rate. This phase occurs when an essential nutrient for bacterial growth is depleted or when there is an inhibitory factor in the medium.

4. Death phase is phase in which bacteria die.