What is mitosis, its stages, types and meaning

In the process of reproductive functions of living organisms, cell division occurs . Mitosis is the most common way of reproducing eukaryotic cells through their indirect division. Its biological role consists in the uniform distribution of chromosomes between the subsequent daughter nuclei, which guarantees the formation of an identical genetic type of cells and ensures the preservation of heredity in the line of subsequent generations of cells.

What is mitosis? It is the fundamental process of the individual development of the organism and its successive transformations in relation to the morphological, physiological and biochemical, which together makes up ontogeny. Due to myotic division, the number of cell populations of plant origin increases. The division of the fertilized egg and the progress of the main mass of tissues of animal origin occurs on the same principle.

The stages of myotic division

The duration of mitosis in Tissues of animal origin lasts up to 60 minutes, in plant tissues - up to 3 hours. Mitosis and its phases, Based on morphological properties, is conventionally divided into 5 periods, allowing to establish thoroughly what is mitosis:

1. Prophase is the stage of myotic division, characterizing the spirals of chromosomes from two similar chromatids with the subsequent formation of a mitosis apparatus.

2. Prometaphase - the period of rapid collapse of the nuclear envelope into small parts, identical to the endoplasmic reticulum.

3. Metaphase is a prolonged stage of myotic division of the cell, consisting of two periods: metakineza - the concentration of chromosomes in the region of the fission spindle in the form of an equatorial plate - and the separation of chromosomes into chromatids.

4. Anaphase is the fast phase of division, during which the chromatids are separated and distributed at opposite poles. It's only a few minutes.

5. The telophase is the final stage of mitosis, during which the movement of chromosomes ceases, the miotic apparatus is destroyed, daughter nucleoli are formed, a nuclear envelope is formed, and the cell division into two independent units.

Types of mitosis

What is mitosis and what is its classification? More precisely, this can be established by the method of determining its types. Given the unique specificity of mitosis manifested in different fission groups, certain types of its classification, applicable to one taxon, are not comparable with others. One of the main features used in the formation of typology are the characteristic actions of the nuclear envelope, in relation to the behavior of which there are three types of mitosis:

1. Closed mitosis is characterized by the fact that spindle formation and subsequent fission occurs inside the nucleus without destroying its shell.

2. Open mitosis is determined by the decay of the nuclear envelope in the process of cell division.

3. Semi-closed mitosis. What is mitosis of this type can be determined from the decay of the shell exclusively at the poles of the myotonic spindle, with the subsequent formation of "windows of polarity".

Another defining sign of the type of mitosis is the kind of symmetry of the spindle. Concerning this characteristic in fundamental biology, the concepts are divided:

- pleuromitis (when the spindle symmetrically or asymmetrically consists of two parts);

- orthomitosis (when bipolar symmetry of the spindle is detected, and in the metaphase stage an equatorial plate is formed).

Meaning of mitosis

In the process of mitosis, the cells reproduce the same. It is the most important tool for preserving the chromosome set. The main role of mitosis is to copy genetic information. This process affects growth and development, cell movement, regeneration and asexual reproduction.