Cytokinesis is the process in the cell cycle during which the cytoplasm of a parental cell is divided into two daughter cells. It is the final stage of cell division, following the processes of mitosis (in eukaryotic cells) or meiosis. While mitosis and meiosis are responsible for the division of the nucleus, cytokinesis specifically involves the division of the cellular cytoplasm and other organelles.
Key points about cytokinesis include:
- Timing: Cytokinesis typically begins after the chromosomes have been evenly distributed into the daughter nuclei during mitosis or meiosis.
- Process (Animal Cells): In animal cells, cytokinesis is achieved through a process known as cleavage. A contractile ring, composed of actin and myosin filaments, forms just beneath the cell membrane. The ring contracts, pinching the cell’s membrane and creating two separate daughter cells.
- Process (Plant Cells): Plant cells undergo a slightly different process due to the presence of a rigid cell wall. During plant cell cytokinesis, a structure called the cell plate forms at the center of the cell. The cell plate consists of vesicles containing cell wall materials. These vesicles fuse, gradually forming a new cell wall that separates the two daughter cells.
- Result: At the end of cytokinesis, two genetically identical daughter cells are produced, each with its own nucleus and a portion of the cytoplasm and organelles from the original cell.
It’s important to note that cytokinesis is a distinct process from mitosis or meiosis, which primarily deal with the separation of genetic material in the form of chromosomes. Together, mitosis or meiosis (nuclear division) and cytokinesis (cytoplasmic division) ensure the proper distribution of genetic material and cellular components to the daughter cells.