Cytokinesis vs Mitosis
The cell cycle is the process of division allowing the duplication of cells; that is, two new daughter cells from a mother cell. It basically involves the duplication of the genome, its segregation, and the division of cellular contents. The cell cycle consists of two main phases called interphase and M phase. Interphase can be further divided into three main phases including G1 (gap phase 1), S (synthesis) and G2 (gap phase 2). Mitosis and cytokinesis together are considered as the mitotic (M) phase of the cell cycle. Cytokinesis usually occurs in conjunction with mitosis, but there are certain cells where mitosis and cytokinesis occur separately.
The process of cytoplasmic division of the daughter cells is known as cytokinesis. It usually begins in late anaphase and continues throughout telophase and ends sometime after a nuclear membrane reformation around each daughter nucleus. As the new nuclei form in the late anaphase, the cytoplasm constricts along the plane of the metaphase plate forming a cleavage furrow in animal cells or a cell plate in plant cells. In the animal cells, the cleavage furrow formation is driven by a ‘contractile ring’, which is made up of a ring of proteins, including contractile assembles of filamentous protein actin and motor protein myosin II. This contractile ring surrounds the cell equator beneath the cell cortex and bisects the axis of chromosome segregation. This is done by contracting the filamentous protein ring to shrink and pull the membrane inward.
Unlike the animal cells, the plant cells have rigid cell walls. Therefore, plants and animals have different processes of cytokinesis. In the plant cells, an expanding membrane partition called a cell plate forms to divide the cells. The cell plate grows outward and fuses with the plasma membrane, to form two new daughter cells. Cellulose is then laid down on the new plasma membrane, forming the new two cell walls.
Mitosis is a complex and highly regulated process that occurs exclusively in eukaryotes. It involves the assembling of the spindle, binding the chromosomes, and moving the sister chromatids apart. This process is the most important step in the separation of the two daughter genomes. The sequence of events of mitosis can be divided into five phases, namely, prophase, prometaphase, metaphase, anaphase, and telophase.
Mitosis takes about two hours to complete from prophase, to telophase. First, the mitotic apparatus forms during the prophase. During prometaphase, chromosomes attach to the spindle. In anaphase, the chromatids separate, and in metaphase, chromosomes align at the equator. Finally, the reformation of nucleus occurs during the telophase.
What is the difference between Cytokinesis and Mitosis?
• Mitosis involves the division and duplication of the cell’s nucleus or separation of duplicated chromosomes whereas cytokinesis involves the division of the cytoplasm to form two distinct, new daughter cells.
• The process of mitosis can be divided into five stages; prophase, prometaphase, metaphase, anaphase, and telophase, but the process of cytokinesis does not have such phases.
• Five stages of mitosis act together to separate duplicated chromosomes whereas cytokinesis divides a cell into two separate cells.
• Mitosis is followed by cytokinesis.
• Mitosis can occur without cytokinesis, forming single cells with multiple nuclei (Ex: certain fungi and slime moulds).
• Mitosis takes more time to complete than cytokinesis does.