Cytokinesis:

Karyokinesis is the division of nucleus during mitosis or meiosis which is followed by cytokinesis. Cytokinesis involves the division of cytoplasm of a cell into two. It is initiated in the beginning of telophase and is completed by the end of telophase.

Cytokinesis is achieved in animal cell by cleavage furrow appears. The furrow deepens as spindle breaks down. The ingrowing constrictions join and separate two daughter cells.

It is achieved in plant cell by cell plate formation between the two daughter nuclei. This grows from the middle towards the periphery and finally joins the cell wall. The cell plate represents the middle lamella between the walls of two adjacent cells.

Image showing Cytokinesis plant cells.

Image Showing Cytokinesis Plant Cells.

Image showing Cytokinesis plant cells.

Significance of Mitosis:

  • It keeps the chromosome number constant and genetic stability in daughter cells, so the linear heredity of an organism is maintained.

  • It helps in growth and development of Zygote into adult through embryo formation.

  • It provides new cells for repair and generation of lost parts and healing of wounds.

  • It helps in asexual reproduction (Vegetative reproduction in plants takes place by mitosis).

  • It keeps a check on cell size as overgrown cell is induced to divide.

Mitosis (Limited or unlimited):

Growth by mitosis occurs in a limited or controlled manner to the extent it is required in the body. But at times due to some special causes it may continue to unlimited situation which may cause Cancer.

In plant tissue culture, a cell from a plant can be grown in a nutrient medium, where it divides repeatedly by mitosis to give an undifferentiated cell mass called callus which differentiates into a plant. In animals, stem cell culture is also based on the ability of a cell to divide.

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