What Is Mitosis?

In cell biology, mitosis is part of the cell cycle. During the process of mitosis, four main stages happen. The phases are prophase, metaphase, anaphase, and telophase. Each stage has their specific meaning.

Mitosis is a cell division responsible for asexual reproduction in other words repair, growth, and maintenance of multi-cellular organisms. During mitosis, the nucleus and its contents divide evenly into two daughter nuclei and cytokinesis happens. The process takes place in the cell nuclei of eukaryotic cells only.

Interphase is not really part of mitosis though it does copy its DNA in the preparation of the process. The cell obtains nutrients and metabolizes them, grows, reads its DNA, and conducts other "normal" cell functions. This phase is formally referred as the resting place but does not describe a cell. Rather it lives active and prepares for later cell division.

Prophase is the first stage in mitosis. As the chromosomes coil up, prophase takes responsibility for the chromatin to condense into two rod-shaped structures which are called chromosomes. After the chromatins condense into chromosomes the nucleolus disappears and spindles are formed. Prophase is known as chromatin condensation since there are now two identical copies of each chromosome in the cell because of the genetic material that was replicated in the interphase. The two copies that were made by prophase are called sister chromatids. Centromere which is a DNA element that is on every chromosome keeps the sister chromatids attached.

Metaphase is the second process of cell division. Between prophase and anaphase. Since the nuclear has vanished and the chromosomes have condensed which means that they converted tightly coiled. Now metaphase begins with the centromeres of the chromosomes which arrange themselves on the metaphase plate. Basically, the spindles line up across the equator of the dividing cell. The reason why is because the chromosomes become attached to the spindle fibers.

The third stage is Anaphase after metaphase when replicated chromosomes are divided. Anaphase begins when the duplicated centromeres of the sister chromatids separate and move towards opposite poles of the cell due to the action of the spindle. It depends where the centromere is positioned along the chromosome because a characteristic shape appears. The two shapes that come into view give a V and J shapes. These shapes appear during the chromosome movement. Also, later in anaphase the chromosomes reach their overall maximum condensation. This helps the chromosome separate and the nucleus to reappear.

Telophase is the official final stage of mitosis. Since telophase is after anaphase the effects are reversed. After the chromosomes arrive at the poles of the cell, each pole has a haploid chromosome set although each chromosome is in duplicate form. So, what happens in telophase is that a new nuclear envelope forms, the chromosomes unfold back into chromatin, nucleoli reappears, and the cell continues to elongate. At the end of everything the result is two genetically identical daughter nuclei. But the rest of the cell may continue dividing by cytokinesis to produce two daughter cells.


 By Crystal Hernandez


Article Source:  What Is Mitosis?