What is Cytokinesis?
Cytokinesis is a process of cell division through which the cytoplasm of a cell divides into two daughter cells, different from each other.
This process is characteristic of eukaryotic cells, and takes place after mitosis or meiosis, when the last process of the cell cycle is ending.
However, this process of cell division does not occur in all cells, since some can duplicate without having to divide their cytoplasm, as in the case of some fungi or heart muscle cells. In this sense, cytokinesis is more common in animal cells than in plant cells.
Cytokinesis begins during anaphase and ends with the telophase of mitosis. In this sense, in mitosis the cell’s DNA duplicates and divides between the two daughter cells.
Anaphase is the process by which the chromosomes are divided and placed in the opposite of the stem cell that will be divided.
For its part, telophase is when chromatids (filaments of chromosomes) reach these opposite poles of the cell. In this way, the formation of new cell membranes for the nuclei of the new daughter cells begins.
Once this occurs, cytokinesis begins, which is the final stage of cell division in both animal and plant cells.
Cytokinesis in animal cells
In animal cells, the cytokinesis process involves the formation of a division groove on the cell surface that extends and deepens to divide the cell in two, and this is due to the contraction generated by the contractile ring, composed of actin filaments. , myosin and other structural and regulatory proteins.
As the ring narrows the groove will be larger and the cytoplasm will be strangled to the point of cell separation. Finally, the two daughter cells are formed.
During the anaphase stage, the contractile ring fits under the plasma membrane and gradually contracts, thus fusing and inserting a new membrane next to the ring, which helps to compensate for the increase in surface during division of the cytoplasm and seals the formation of the two new daughter cells.
In this sense, cytokinesis can be said to be carried out in four stages, which are initiation, contraction, membrane insertion and termination.
Cytokinesis in plant cells
Cytokinesis in plant cells is carried out after the formation of a separation septum known as a fragmoplast, which arises from the accumulation of vesicles that come from the Golgi Apparatus and that contain cell wall material.
Once the fragmoplast contacts the cell walls, the septum will form in the middle of the cell, making cell division possible.