Reproduction of Bacteria


Bacteria are prokaryotic organisms that reproduce asexually. Bacterial reproduction most commonly occurs by a type of cell division called binary fission. Binary fission involves the division of a single cell, resulting in the formation of two cells that are genetically identical. In order to grasp the binary fission process, it is useful to understand the structure of bacterial cells.

Bacteria have different cell shapes.

The most common bacterial cell shapes are spherical, rod-shaped, and spiral. Bacterial cells typically contain the following structures: a cell wall, cell membrane, cytoplasm, ribosomes, plasmids, flagella, and a region of nucleotides.

  • Cellular wall. The outer covering of the cell that protects the bacterial cell and gives it its shape.
  • Cytoplasm. A gel-like substance composed primarily of water that also contains enzymes, salts, cellular components, and various organic molecules.
  • Cell membrane or plasma membrane. It surrounds the cytoplasm of the cell and regulates the flow of substances in and out of the cell.
  • Flagella. Long, whip-like protrusion that aids in cell locomotion.
  • Ribosomes. Cellular structures responsible for protein production.
  • Plasmids. Circular DNA structures that carry genes that are not involved in reproduction.
  • Nucleoid Region. Area of ​​the cytoplasm that contains the single bacterial DNA molecule.

Most bacteria, including Salmonella and E. coli, reproduce by binary fission.

During this type of asexual reproduction, the single DNA molecule is replicated and both copies are attached, at different points, to the cell membrane. As the cell begins to grow and lengthen, the distance between the two DNA molecules increases. Once the bacterium almost doubles its original size, the cell membrane begins to pinch inward at the center.

Some bacteria are capable of transferring fragments of their genes to other bacteria that they come into contact with. During conjugation, one bacterium connects to another through a protein tube structure called a pilus. Genes are transferred from one bacterium to another through this tube.