UNIT FOUR : KINGDOM MONERA
Class : 11
Reproduction in Bacteria
Bacteria usually reproduce by asexual method.
Binary fission
The nuclear material becomes enlarged and divides into two parts. Constriction is made in the middle of the cell on the cell membrane dividing cytoplasm into two parts. Ultimately, a cell is divided into two daughter cells. This method is very common and simplest method of reproduction in bacteria. By this method, about 2500,000 bacterial cells are produced in an hour.
Budding
During the process, small bud is developed on outer side of bacteria cell with cytoplasm. The bud gets enlarged and separated from mother cell.
Gonidia
In cell nuclear material and cytoplasm divides and arranged forming a tiny bodies. Each body having cell wall, cytoplasm and genetic material is called gonidium, which releases out and germinate to produce new bacterial cell.
Endospore
Under unfavorable condition a round spore is formed in the bacterial cell which is thick walled and highly resistant. The spore is oval or spherical called endospore. During endospore formation, the genetic material gets divided into two parts. One part migrates at one end of the bacterial cell. The cytoplasm is constricted at that end by constriction of cell membrane. A spore is then formed at that end. It releases out in the soil and may remain viable for several years. Under favorable condition, it germinates to produce new bacterial cells.
Sexual reproduction
The recombination of genes of bacterial cells through different ways from one to another cell is considered as the sexual reproduction. This is of following types
Transformation
The process of entrance of exogenous DNA from one bacterial cell to another cell is called transformation. The cell which gives exogenous DNA is called donor ant the cell which take is called recipient.
Transduction
The process in which genetic material from one bacterial cell transfers to another bacterial cell by means of viruses is called transduction. The virus evolve in this process is called bacteriophage.
Conjugation
The process in which two bacterial cells conjugate with the help of pili is called conjugation. During the process one bacterial cell transfer the chromosomal segments to another bacterial cell.
Tags:
Biology