What is the first stage of mitosis

Mitosis phases

We will deal with the phases of mitosis in this article. We will also explain to you what is meant by mitosis and what it is used for in nature. This article belongs to our biology / genetics section.

Protozoa multiply by dividing a cell into two daughter cells. These daughter cells then grow to the size of the original cell. This creates two daughter cells that are genetically identical to the original cell. The process of division (nucleus division) is called mitosis in biology or genetics.


Stages of mitosis

The process of mitosis takes place in different phases, which we would like to deal with in this section. As a rule, a distinction is made between the following phases in mitosis: prophase, metaphase, anaphase and telophase.

Phase 1: prophase

The prophase is the first phase of mitosis and can take up to five hours, depending on the organism and cell type. In prophase the chromosomes contract strongly. They condense and become visible under the light microscope through this process. Before division, each chromosome consists of two identical strands (called chromatids), which for the most part separate from each other and are only held together by a so-called centromere.

Now the development of the mitotic spindle begins - sometimes also called the core division spindle, the spindle poles move apart and the nuclear envelope and the nuclear corpuscles disintegrate. The spindle fibers now attach themselves to the centromeres of the chromatids. The chromosomes are exposed at the end of the prophase.

Phase 2: metaphase

In the metaphase there is a spiralization, i.e. the chromosomes are further shortened and thickened. The chromosomes are arranged in one plane (equatorial plane) and the sister chromatids point to the opposite spindle poles. In the metaphase it is possible to differentiate the different chromosomes according to shape and size. The spindle fibers attach themselves to the centrometer from both sides.

Phase 3: anaphase

The chromatids are first completely separated from each other by shortening the spindle fibers and the support of caulking fibers and then drawn to the two opposite poles. This gives each pole a set of chromatids. The duration of the anaphase varies widely from 2 to 20 minutes.

Phase 4: telophase

In the telophase the chromatids unscrew and unfold. You will then go into the working form. Nuclear corpuscles and nuclear membrane form anew. After cell division, each daughter cell has the same number of chromosomes as the parent cell.


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