BACTERIA LIFE CYCLE
bacteria is a group of microscopic, single-celled organisms that inhabit virtually all environments .they have both positive and negative effects on the environment. they are responsible for much food spoilage, and for disease, but they are also made use of , for example, in the pickling process and fermentation of milk, as well as in the manifacture of vitamins and a variety of enzymes and hormones. In autecological studies, bacterial growth in batch culture can be modeled with four different phases: lag phase , exponential or log phase, stationary phase, and death phase .
first of all, in lag phase bacteria adapt themselves to growth conditions. It is the period where the individual bacteria are maturing and not yet able to divide. During the lag phase of the bacterial growth cycle, synthesis of RNA, enzymes and other molecules occur. So in this phase the microorganisms are not dormant. Bacteria do not grow during the lag phase. However, they do adjust to their environment and metabolize for example, they produce vitamins and amino acids needed for division. They begin making copies of their DNA, and if the environment supplies plenty of nutrients, the lag phase may be very short. Then the bacteria will proceed to the next phase of their life .
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Second , Log or Exponential Phase is a period characterized by cell doubling .The number of new bacteria appearing per unit time is proportional to the present population. If growth is not limited, doubling will continue at a constant rate so both the number of cells and the rate of population increase doubles with each consecutive time period. During the log or exponential phase, bacteria multiply rapidly, even exponentially. The time it takes for a culture to double is called "generation time," and under the best conditions, the fastest bacteria can double in about 15 minutes. Other bacteria take days. Within a bacterium, the DNA copy...