Table of contents | |
What is Mitosis? | |
Features of Mitosis | |
Stages of Mitosis | |
Functions of Mitosis | |
Significance of Mitosis |
Cell division is the driving process of reproduction at the cellular level. Most eukaryotic cells divide in a manner where the ploidy or the number of chromosomes remains the same, except in the case of germ cells where the number of chromosomes is halved.
Mitosis Diagram showing the different stages of mitosis
Mitosis is the phase of the cell cycle where the nucleus of a cell is divided into two nuclei with an equal amount of genetic material in both the daughter nuclei. It succeeds the G2 phase and is succeeded by cytoplasmic division after the separation of the nucleus.
Mitosis is essential for the growth of the cells and the replacement of worn-out cells. Abnormalities during mitosis may alter the DNA, resulting in genetic disorders.
The processes occurring during mitosis have been divided into different stages.
Right before prophase, the cell spends most of its life in the interphase, where preparations are made before the beginning of mitosis (the DNA is copied). However, since the actual process involves the division of the nucleus, prophase is technically the first stage of this process.
The different stages of mitosis occurring during cell division are given as follows-
Before entering mitosis, a cell spends a period of its growth under interphase. It undergoes the following phases when in interphase:
Prophase immediately follows S and G2 phase of the cycle and is marked by condensation of the genetic material to form compact mitotic chromosomes composed of two chromatids attached at the centromere. The completion of prophase is characterised by the initiation of the assembly of the mitotic spindle, the microtubules and the proteinaceous components of cytoplasm that help in the process. The nuclear envelope starts disintegrating.
Prophase
Telophase is followed by cytokinesis, which denotes the division of the cytoplasm to form two daughter cells. Thus, it marks the completion of cell division.
Cytokinesis is the physical process of cell division, which divides the cytoplasm of a parental cell into two daughter cells. It occurs concurrently with two types of nuclear division called mitosis and meiosis, which occur in animal cells. Mitosis and each of the two meiotic divisions result in two separate nuclei contained within a single cell.
Cytokinesis performs an essential process to separate the cell in half and ensure that one nucleus ends up in each daughter cell. Cytokinesis starts during the nuclear division phase called anaphase and continues through telophase. A ring of protein filaments called the contractile ring forms around the equator of the cell just beneath the plasma membrane. The contractile ring shrinks at the equator of the cell, pinching the plasma membrane inward, and forming what is called a cleavage furrow. Eventually, the contractile ring shrinks to the point that there are two separate cells each bound by its own plasma membrane.
Following are the two important functions of mitosis:
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1. What is mitosis and why is it important? |
2. What are the stages of mitosis? |
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