Death phase

Definition

The death phase is the final stage of microbial growth where the number of dying cells exceeds the number of new cells being produced. This results in a net decrease in the overall population of microbes.

5 Must Know Facts For Your Next Test

1. During the death phase, nutrient depletion and waste accumulation are primary reasons for cell death.
2. Cell lysis often occurs during this phase, releasing cellular components into the environment.
3. The death rate can follow an exponential decay pattern, similar to how growth occurred exponentially in earlier phases.
4. Not all cells die immediately; some may enter a dormant state or form spores to survive harsh conditions.
5. This phase can be observed using methods such as viable plate counts and turbidity measurements.

Review Questions

• What are two primary factors that contribute to cell death during the death phase?
• How does the rate of cell death compare to cell production in this phase?
• What are some methods used to observe and measure microbial populations during the death phase?

Related terms

Lag Phase:

The initial phase where microbes acclimate to their environment before starting active division.

Log Phase: The period of exponential growth where microbes divide at a constant and rapid rate.

Stationary Phase:

A plateau period where the rate of cell growth equals the rate of cell death due to limited resources.