binary fission

Bacterial cells were regenerated by two divisions. The two daughter cells generated are genetically identical. (Photo: Dr. Vincent A. Fischetti, Institute of Bacterial Oncology Immunology, Rockefeller University)

Bisection is a method of asexual reproduction that is used by most prokaryotes. In bifurcation, live cells are divided into two equal or nearly equal parts. It starts with the DNA of the cell to be replicated. Each circular DNA strand then attaches to the plasma membrane. The cell elongates, and the two chromosomes separate. The plasma membrane is then invaginated (inwards) and the cell is divided into two daughter cells by a process called cytokinesis.

Bisection theoretically leads to two identical cells. However, bacterial DNA has a relatively high mutation rate. This rapid genetic change is the reason that bacteria develop resistance to antibiotics and can help them to invade various environments.

Like more complex organisms, bacteria also have mechanisms for exchanging genetic material. It is not equivalent to sexual reproduction, but the final result is that the bacteria contains combinations of traits from two different parental cells. To date, three different exchange methods have been identified in bacteria. (Refer to gene introduction.)

The ligation involves the direct ligation of two bacteria, which allows their circular DNA to undergo recombination. Bacteria can also be transformed by absorbing DNA residues from dead bacteria and integrating these fragments into their own DNA. Finally, bacteria can exchange genetic material through a process called transduction, in which the gene enters and exits the cell through bacterial virus (called phage) or plasmid (autonomous self-replicating extra-chromosomal DNA).

Bisection is the process by which asexual reproduction occurs in bacteria. During bifurcation, one creature becomes two separate creatures. Bisection is also used to describe repeating organelles in eukaryotes and is sometimes used to describe the reproduction of invertebrates vegetatively propagating by germination. Those cells undergo mitosis, but this process is called two divisions because it produces one to two organisms. With similar multiple division, organisms are divided into two or more

Bivariart is the main method of breeding prokaryotes. In protists, bisections are usually classified according to the axis of cell separation, such as lateral and longitudinal. In certain creatures such as aphids and anal anastomotic polyps, normal lateral division is called strobolation. Typically, this results in a series of split products called stellovirus, aphid arthropods, and lepidopteran jellyfish spines, each precursor or flashing mature in tandem and from the end of the strobilus Are separated. Several metazoan (multicellular) species frequently divide into several units at the same time. This is a process called fragmentation. The division and division of worms usually represents direct breeding, where each part plays a lost part and becomes a complete new animal.

The speed between species is different, but bipartition is usually very fast. In the case of Escherichia coli, cells usually divide at 37 ° C every 20 minutes. As new cells undergo secondary division in turn, the time required for bisection is also the time to double the number of cells required for bacterial culture. Therefore, this period can be called doubling time. Several species other than E. coli can have faster or slower doubling times: some tuberculosis strains can have doubling time of nearly 100 hours. Since the growth of bacteria is limited by factors such as the availability of nutrients and available space, the two divisions of bacterial culture occur at a much slower rate when entering the stationary phase of proliferation.