What type of asexual reproduction is bacteria

Once the bacterium just about doubles its original size, the cell membrane begins to pinch inward at the center. Finally, a cell wall forms which separates the two DNA molecules and divides the original cell into two identical daughter cells. There are a number of benefits associated with reproduction through binary fission. A single bacterium is able to reproduce in high numbers at a rapid rate. Under optimum conditions, some bacteria can double their population numbers in a matter of minutes or hours.

Another benefit is that no time is wasted searching for a mate since reproduction is asexual. In addition, the daughter cells resulting from binary fission are identical to the original cell. This means that they are well suited for life in their environment. Binary fission is an effective way for bacteria to reproduce, however, it is not without problems. Since the cells produced through this type of reproduction are identical, they are all susceptible to the same types of threats, such as environmental changes and antibiotics.

These hazards could destroy an entire colony. In order to avoid such perils, bacteria can become more genetically varied through recombination.

Recombination involves the transfer of genes between cells. Bacterial recombination is accomplished through conjugation, transformation, or transduction. Some bacteria are capable of transferring pieces of their genes to other bacteria that they contact. During conjugation, one bacterium connects itself to another through a protein tube structure called a pilus.

Genes are transferred from one bacterium to the other through this tube. Some bacteria are capable of taking up DNA from their environment. These DNA remnants most commonly come from dead bacterial cells. During transformation, the bacterium binds the DNA and transports it across the bacterial cell membrane. The plasmid can be copied in the receiving cell and passed on to its descendants.

Transduction: In this type of sexual reproduction of bacteria, foreign genes are transferred into a bacterial cell with the help of a virus. These viruses are called bacteriophage and they are not virulent. The virus acts as a carrier vehicle and passes over genes from one host to another. Transducing bacteriophages may carry the same genes in which the reproduction method would be known as restricted transduction.

They can also carry different genes at different times in which the reproduction process would be known as generalised transduction. Conjugation: This process was first discovered in Escherichia coli by Tatum and Lederberg in They found that two different types of nutritional mutants grown together on minimal medium produced an occasional wild type. The male or donor cell possesses 1 to 4 sex pili on the surface and fertility factor transfer factor, sex factor in its plasmid.

It contains genes for producing sex pili and other characters needed for gene transfer. Sex pili are 1to 4 narrow protoplasmic outgrowths. The sex pili and fertility factor are absent from the female or recipient cells.

If these two types of cells happen to come nearer, a pilus of a male cell establishes a protoplasmic bridge or conjugation tube with the female cell. B Division forms a large mother cell and two small offspring cells. C The smaller cells contain DNA and become fully engulfed by the larger mother cell. D The internal offspring grow within the cytoplasm of the mother cell. E Once offspring development is complete the mother cell dies and releases the offspring.

Our lab studies the mechanisms of intracellular offspring development in Epulopiscium and Metabacterium polyspora. We are interested in what mechanisms are conserved between these unusual reproductive processes and endospore formation. We hope to gain an understanding of how this novel form of cell reproduction developed over time and how it benefits these intestinal symbionts.

Google Tag Manager. Binary Fission and other Forms of Reproduction in Bacteria. Binary Fission Most bacteria rely on binary fission for propagation. Some Unusual Forms of Reproduction in Bacteria: There are groups of bacteria that use unusual forms or patterns of cell division to reproduce. Baeocyte production in the cyanobacterium Stanieria Stanieria never undergoes binary fission.

Budding in bacteria Budding has been observed in some members of the Planctomycetes, Cyanobacteria, Firmicutes a. Intracellular offspring production by some Firmicutes Epulopiscium spp.

In certain plants, such as bryophytes and certain ferns, the gametophyte may give rise to a sporophyte-looking offspring but with a ploidy level of a gametophyte. This is referred to as apogamy. Then, there is also an instance wherein their sporophyte may give rise to a gametophyte-looking offspring but with a ploidy level of a sporophyte.

This, in turn, is called apospory. In flowering plants, the seed production from unfertilized ovules is referred to as agamospermy. There are two major types: gametophytic apomixis and sporophytic apomixis.

In gametophytic apomixis , the embryo arises from an unfertilized ovum from a gametophyte that came from a cell that did not complete meiosis. The major types of gametophytic apomixis are diplospory where the megagametophyte arises from a cell of the archesporium and apospory wherein the megagametophyte arises from the other cell of the nucellus.

In sporophytic apomixis also called adventitious embryony or nucellar embryony , the embryo arises not from a gametophyte but from the cells of the nucellus or of an integument. Many bacteria reproduce by binary fission. The parent bacterial cell produces two identical clone cells by first creating a copy of the DNA molecule. Then, this is followed by chromosome segregation wherein DNA is pulled apart toward the opposite poles of the dividing cell.

The cell constricts at the equatorial plane cytokinesis , separating the cellular contents into two new cells. The process is similar to mitosis in eukaryotes. However, there is no spindle apparatus involved. The duration varies between bacterial species.

When food is scarce and the conditions are not suitable, plasmodium slime molds produce stalked reproductive fruiting bodies sporangia that contain spores. At the apical portion of the sporangia, the cells undergo meiosis, producing haploid spores that are dispersed by wind. When the conditions become favorable again, e. The haploid cells are involved in the sexual phase of the plasmodium slime mold life cycle. Cellular slime molds also have asexual and sexual phases in their life cycle.

However, when the conditions are not favorable, they come together as a pseudoplasmodium. They form a pseudoplasmodium because the cells remain distinct, each with a nucleus of its own. A real plasmodium in slime molds is a single mass of cytoplasm undivided by membranes and containing multiple nuclei. Nevertheless, both the cellular slime molds and plasmodium slime molds produce fruiting bodies. Some of the cellular slime molds in the colony form the stalk whereas the others form the sporangium where haploid spores are produced and released from.

Each spore germinates into an individual amoeba-like cell. The New Mexico whiptails Aspidoscelis neomexicanus are lizards that are all females. They reproduce asexually by parthenogenesis by doubling the chromosomal number twice to restore diploidy.

So to begin with, they produce eight copies of each chromosome. Thus, after two rounds of cell division, four daughter cells, each with two sets of chromosomes instead of just one. Although they do not need a male mate, they still display mating behavior with other females.

A female whiptail mounts another female whiptail. This pseudocopulation behavior seemingly promotes ovulation. While other asexuals produce genetic clones, the New Mexico whiptails are still able to produce genetically-diverse offspring. How is that possible? Do you think humans are capable of reproducing asexually? Come and share with us what you think. Try to answer the quiz below to check what you have learned so far about asexual reproduction.

Smith, J. Maynard The Evolution of Sex. Cambridge University Press. ISBN Otto, S. Sexual Reproduction and the Evolution of Sex. Nature Education 1 1 Fields, A. Facultative parthenogenesis in a critically endangered wild vertebrate. Current Biology, 25 11 , R—R Wikipedia Contributors.