Question

What would be areason why a cell does not have death phase in a bacterial growth curve?

Answer 1

Bacteria reproduces by binary fission. Bacterial growth curve shows the events in a bacterial population. There are four distinct phases in bacterial growth curve. They are: lag phase, log phase, stationary phase, and death phase.

Bacteria die during the death phase or decline phase. Death occurs due to lack of nutrients, unfavorable temperature, pH, accumulation of metabolic waste products and toxic products, etc. Cell death usually occurs as a result of cell lysis. During this phase, the bacterium loses its ability to reproduce. The process of death is rapid and at uniform rate. Death is also an exponential process but is slower than the exponential growth.

Some bacteria are able to resist and are able to survive in harsh environmental conditions. One such mode of resistance is by involution. Involution is a process that occur under unfavorable conditions during which bacteria may assume unusual shapes. Apart from this, some bacteria may also form endospores in order to survive hostile conditions. These events help the cells to overcome adverse conditions and thus will be able to survive. Hence, such bacterial cells will not have death phase in a bacterial growth curve.