Any organism, consisting of billions and trillions of diverse functioning and externally not similar cells, is derived from the same fertilized egg m

Totipotency

Any organism, consisting of billions and trillions of diverse functioning and externally not similar cells, is derived from the same fertilized egg — the zygote. This means that from one non-specialized very large cell initially form by cleavage hundreds and thousands of the same non-specialized, but only much smaller cells. Then, during the following divisions, gradually changes the shape and size of cells, and they start to specialize. From them form germ layers, in which goes further specialization of cells, resulting in the formation of some organs of the body and appears a multicellular organism.

All these successive stages of individual development are the result of cell differentiation — the formation from a common parent cell a huge variety by the structure and functions of the so-called specialized cells. At the heart of this process lays the mechanism of implementation of hereditary information, consisting in the fact that at different stages of development of the organism, in certain of its cells, different groups of genes are active.

Property of zygote or of other cells to give rise to a new organism is called a totipotency (from Latin “totus” — “whole”, and “potential” — “strength”, “power”). The fact that they are not simply have a complete set of genetic material (it has each asexual cell of the body), but unlike other somatic cells of the adult organism in which some genes are active and on which there is a synthesis of mRNA and the other are repressed, in them all genes retain potent activity. This state of the cells, for example in mammals, remains unchanged until the morula stage, and in many simply organized multicellular animals and in some plants even in the adult organism cells retain totipotency. Taken from http://worldofschool.org

The ability of some organisms to vegetative reproduction arises right because of the cell totipotency. Moreover, this ability in different groups of organisms shows that all the genetic material stores in each cell of the body. Vegetative reproduction is usually inherent in fungi, algae and many species of seed plants, among which it manifests in different forms. In animals, reproduction by parts of his body in a natural environment is found only at rather lower organized creatures — sponges, coelenterates, flat and some polychaete worms.

Categories:
Questions:
  • What is totipotency?