Mitosis and Cytokinesis

Comprised of five unique stages, mitosis is a form of division where a cells genetic material is partitioned between two daughter cells.  First, during prophase in humans, nucleic chromatin condenses into x-shaped chromosomes composed of sister chromatid pairs attached at centromere junctions.

Concurrently, outside the nucleus, two l-shaped organelles called centrosomes migrate to opposite cell sides. As they do so, microtubule rods begin to grow from each, either towards the cell's interior or exterior forming a web-like spindle apparatus.

Next, the nuclear envelope dissolves during prometaphase, exposing the chromosomes to the cells other contents. Protein structures also appear on both sides of the centromeres, one for every chromatin.

Once these kinetochores form, extending interior microtubules fasten to them, with each sister chromatid being tethered to a different cell pole.

Mitosis then progresses to metaphase where the spindle apparatus rearranges the chromosomes so that they are similarly oriented in a fixed row along the cell's equator.

With anaphase, kinetochore afixed microtubules shorten and sister chromatids, now individually referred to as chromosomes, are dragged apart. These and other microtubule dynamics also elongate the cell.

Finally, the chromosomes land at opposite cell sides during telophase, where upon the spindle apparatus disbands. The genetic material loosens, and two nuclear envelopes, one around each chromosome set, arise.

During telophase, in a distinct process called cytokinesis, the cell is cytoplasmically divided. Thus, the end result of mitosis is a cell pair genetically identical to their precursor.