Growth and Reproduction of Bacteria

Growth of Bacteria:

Cell Growth:

If conditions are favorable, cell division is normally followed by a period of enlargement and growth. Through the absorption of water and food manufactured by the protoplasm, the cell enlarges to its original size. Under favorable conditions of moisture, nutrition, pH, and temperature some kinds of bacteria.

Cell Division:

Cell division requires the doubling of all cell constituents and their orderly partitioning into the daughter cells. The first step in cell division is the doubling of the DNA complement of the nuclear body, which occurs through the separation of the two strands and replication along each strand of a new complementary strand. Because of the enormous length of the DNA, the cell faces a problem in partitioning the doubled DNA between the two daughter cells. It is thought that the DNA molecule is attached at some point to the cell membrane and after replication, each one of the double strands while still attached, swings toward one of the two cell halves.

Only after this slip has been accomplished can the new cross wall form. At the time, the new cross wall, a mesosome of the membrane can be seen attached to the growing cross wall and it is likely that this mesosome plays some role in the synthesis of a cross wall. The DNA is probably attached to the other end of the same mesosome. The highly coordinated process, DNA doubling/ DNA partitioning/ cross wall formation is the equivalent of the mitotic process in eukaryotic organisms.

Reproduction of Bacteria:

In bacteria, asexual and sexual methods of reproduction are known.

Asexual Reproduction:

It is the commonest method of reproduction found in bacteria. Binary fusion is simply the multiplication of cells by division. The dividing cell elongates and if the cell is spherical the elongation is very much restricted and a rod-like bacterium elongates almost double its size.

The protoplasm mass then divides into two equal halves by a transverse wall or constriction. The two daughter cell soon grow to maturity and again divide within 20 minutes of their formation. This asexual method is very quick and if favorable conditions prevail a single organism may produce 1677216 cells within 12 hours. But such favorable conditions never exist for a long period in nature.

Sexual Reproduction:

Sexual reproduction involving the fusion of two different cells and a transfer of hereditary factors occurs in bacteria although infrequently. Genetic recombination occurs in those bacteria that have been carefully studied and presumably occurs in other species as well.