sitokineesi

Cytokinesis is the final stage of cell division in eukaryotic cells. It is the process by which the cytoplasm of a single eukaryotic cell is divided to form two daughter cells. This follows nuclear division, which is called mitosis in somatic cells and meiosis in germ cells. Cytokinesis typically begins during the anaphase or telophase of mitosis and meiosis.

In animal cells, cytokinesis occurs through the formation of a cleavage furrow. A contractile ring composed of actin and myosin filaments assembles beneath the plasma membrane. This ring constricts, pulling the membrane inward and eventually pinching the cell into two separate daughter cells. The precise mechanism involves motor proteins like myosin that interact with the actin filaments, causing them to slide past each other and shorten the ring.

Plant cells, on the other hand, undergo cytokinesis by forming a cell plate. Vesicles derived from the Golgi apparatus move to the equatorial region of the cell. These vesicles fuse together to form a flattened, membrane-bound sac called the cell plate. The cell plate grows outward from the center towards the cell walls, eventually dividing the parent cell into two daughter cells. A new cell wall is then laid down between the two daughter cells.

Cytokinesis is a crucial process for growth, development, and reproduction. It ensures that each new cell receives a complete set of chromosomes and a sufficient amount of cytoplasm to function independently. Errors in cytokinesis can lead to aneuploidy, where cells have an abnormal number of chromosomes, which can have significant consequences for the organism.