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Jun 4, 2024 · There are four distinct phases of the growth curve: lag, exponential (log), stationary, and death. The initial phase is the lag phase where bacteria are metabolically active but not dividing. The exponential or log phase is a time of exponential growth.
- Regina Bailey
Mar 28, 2024 · The curve typically consists of four distinct phases: lag phase, log phase (exponential growth phase), stationary phase, and death phase. These phases reflect the changes in the number, size, and mass of bacterial cells during their growth cycle.
- Lag Phase: Lag phase represents a period of active growth during which bacteria prepare for reproduction, synthesizing DNA, various inducible enzymes, and other macromolecules needed for cell division.
- Log or Exponential Growth Phase: Bacterial cells prepared for cell division during lag phase now enter into the log phase or exponential growth phase during which the cells divide at a maximal rate and their generation time reaches a minimum and remains constant.
- Stationary Phase: Since the bacteria are growing in a constant volume of medium of batch culture, and no fresh nutrients are added, the growth of bacterial population eventually ceases and the growth curve becomes horizontal.
- Death or Decline Phase: After a while, the number of dying cells begins to exceed the number of new-born cells and thus the number of viable bacterial cells present in a batch culture starts declining.
- Stages of the Bacterial Growth Curve. Knowing the difference between the lag, log, stationary, and death phases of a cell growth curve may sound like biology basics but applying that knowledge in active cell culture is a sign of a more fundamental understanding of microbiological processes.
- Lag Phase. This initial cell growth phase is generally characterized by metabolic activity but not growth. The cells utilize media to synthesize the small molecules necessary for replication.
- Log (Exponential Growth) Phase. Once cells enter the exponential growth or log phase, it’s all about the numbers. This is when cells divide by binary fission and the doubling of each generation creates the exponential growth for which the phase is named.
- Stationary Phase. As environmental conditions change and become the limiting factor in growth, cells slow reproduction and enter a stationary phase. In this stage cells are technically still reproducing but it is less than before and roughly equal to the amount of cell death.
Aug 31, 2023 · During the exponential growth phase (log phase) the population increases geometrically as long as there is sufficient food and space for growth. During the stationary phase the population grows slowly or stops growing because of decreasing food, increasing waste, and lack of space. During the death (decline) phase the population dies ...
In autecological studies, the growth of bacteria (or other microorganisms, as protozoa, microalgae or yeasts) in batch culture can be modeled with four different phases: lag phase (A), log phase or exponential phase (B), stationary phase (C), and death phase (D).
Feb 1, 2024 · The death phase follows the stationary phase, characterized by a decline in the bacterial population. Factors such as nutrient depletion, the accumulation of toxic by-products, and environmental stress contribute to the decline in cell numbers.
