Cytokinesis: Unique in Plants and Animals
Cytokinesis, the process of cell division, differs significantly in plants and animals. In animals, cytokinesis occurs through a process called cleavage, where the cell membrane pinches inward, forming a cleavage furrow that gradually separates the two daughter cells. This process is facilitated by a contractile ring composed of actin filaments. In contrast, cytokinesis in plants involves the formation of a cell plate, which eventually develops into a new cell wall that separates the daughter cells.
Different Cell Division Placement in Plants and Animals
Another major difference in cytokinesis between plants and animals is the placement of the cell division site. In animal cells, the cleavage furrow usually forms along the equator of the cell, resulting in the formation of two identical daughter cells. However, in plant cells, the placement of the cell plate is predetermined by the position of the preexisting cell wall. This predetermined location ensures that the new cell walls align properly with the existing ones, maintaining the structural integrity of the plant tissue.
Cell wall influences cytokinesis in plants
The presence of a cell wall in plants also affects the process of cytokinesis. Unlike animal cells, which lack a rigid cell wall, plant cells must deposit materials to build a new cell wall during cytokinesis. Vesicles containing cell wall materials, such as cellulose and other polysaccharides, are brought to the cell plate by microtubules. These vesicles fuse together to form the new cell wall, reinforcing the separation between the daughter cells.
Timing of Cytokinesis: Animals vs Plants
Lastly, the timing of cytokinesis differs in plants and animals. In animal cells, cytokinesis typically occurs after nuclear division, separating the cytoplasm between the two daughter nuclei. However, in plants, cytokinesis occurs simultaneously with nuclear division. This simultaneous process allows the plant to maintain proper symmetry and coordination of growth, ensuring each daughter cell receives an equal distribution of organelles and other cellular components.