The formation of new individuals from their parents is called reproduction. It undergoes reproduction both by asexual and sexual method. Formation of a new individual from a single parent is called asexual reproduction and formation of new individual from two parents is called sexual reproduction.
Bacteria reproduce by three methods-Binary fission, Sporulation and sexual reproduction.
1. Binary fission: During favorable conditions, each bacterium cell divides into two equal daughter cells
2. Sporulation: During unfavorable conditions, gram positive bacteria produce endospores. Endospores are known as resting spores and represent the resting stages of bacteria. The protoplast become rounded and secretes a hard resistant wall around it.Each cell forms a single spore called endospore. During unfavorable condition they remain dormant and when conditions become favorable they are set free from the parent cell .On germination the outer membrane get ruptured and the protoplasmic contents escape as a bacterial cell.
3. Sexual reproduction: Typical sexual reproduction in living organisms involves the formation of gametes and fusion of gametes.
Typical sexual reproduction, meiosis, and crossing over are absent in bacteria. But, sometimes the exchange of genetic material (DNA) takes place. This process is called genetic recombination or gene combination. Genetic recombination (gene transfer) in bacteria is of a primitive type.
In bacteria, DNA transfer (genetic recombination) takes place by 3 ways-conjugation, transduction and transformation.
Conjugation: It is a method of transferring genetic material from one bacterium which is designated as male to a recipient designated as a female
Transduction: It is the process in which the DNA molecule which carries the hereditary characters of the donor bacterium, is transferred to the recipient cell through the agency of the phage particle
Transformation: It is the process in which the DNA molecule of the donor cell, which liberated by its disintegration, is taken up by another recipient cell.