Ans: Karyokinesis is also known as mitosis, which is divided into some phases – prophase, prometaphase, metaphase, anaphase, and telophase. This result in the division of the cell nucleus.
The “first phase”. The nuclear envelope starts to dissociate into small vesicles. The Golgi apparatus, endoplasmic reticulum and other membranous organelles fragment and disperse toward the periphery of the cell. First the nucleolus disappears and then the centrosomes begin to move to opposite poles of the cell. Microtubules extend between the centrosomes (they will eventually form the mitotic spindle), pushing them farther apart as the microtubule fibers lengthen. Condensin proteins help the sister chromatids to begin to coil more tightly and become visible under a light microscope.
The “first change phase”. Many processes that began in prophase continue to advance. Remaining’s of the nuclear envelope fragment. “Mitotic spindle” continues to develop as more microtubules assemble and stretch across the length of the former nuclear area. By coiling more, chromosomes become more condensed and discrete. Each of the sister chromatids develops a protein structure called a kinetochore
in the centromeric region. Mitotic spindle microtubules are attracted and bound by the proteins of the kinetochore.
The “change phase”. All the chromosomes are aligned on a plane called the metaphase plate, or the equatorial plane, midway between the two poles of the cell. Now also, the sister chromatids are still tightly attached to each other by cohesin proteins. The chromosomes are maximally condensed at this time.
It is the “upward phase”. In this the cohesin proteins degrade, and the sisterchromatids separate at the centromere. Each of the chromatids are now called a chromosome The are pulled rapidly towards the centrosome to which its microtubule is attached. The cell elongates visibly (oval shaped) as the polar microtubules slide against each other at the metaphase plate where they overlap.
The “distance phase”. The chromosomes reach the opposite poles and begin to decondense (unravel), relaxing into a chromatin configuration. Then the Mitotic spindles are depolymerized into tubulin monomers that will be used to assemble cytoskeletal components for each daughter cell. Then the nuclear envelopes form around the chromosomes and nucleosomes appears within the nuclear area.
After karyokinesis is done, Cytokinesis happens, by which the cytoplasm of the parent cell divides and results in creating two daughter cells.