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Plant cytokinesis differs from animal cytokinesis, partly because of the rigidity of plant cell walls. Instead of plant cells forming a cleavage furrow such as develops between animal daughter cells, a dividing structure known as the cell plate forms in the cytoplasm and grows into a new, doubled cell wall between plant daughter cells. It ...
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
This is due to there being the possibility of an asymmetric division. This as a result leads to cytokinesis producing unequal daughter cells containing completely different amounts or concentrations of fate-determining molecules. [35] In animals the cytokinesis ends with formation of a contractile ring and thereafter a cleavage.
The bridge is then broken and resealed to form two identical daughter cells during cytokinesis. The breakage is formed by microtubules and the resealing is negated by calcium dependent exocytosis using Golgi vesicles. [2] In comparison, the plant cell septum and the animal cell mid-zone are analogous.
In 1903, Nikolai K. Koltsov proposed that the shape of cells was determined by a network of tubules that he termed the cytoskeleton. The concept of a protein mosaic that dynamically coordinated cytoplasmic biochemistry was proposed by Rudolph Peters in 1929 [12] while the term (cytosquelette, in French) was first introduced by French embryologist Paul Wintrebert in 1931.
During cytokinesis in animal cells, a contractile ring made up of actin filaments forms, and this ring pinches to divide the cell into two daughter cells. [6] The cells are able to separate due to the formation of a cleavage furrow, which pinches in a centripetal fashion (from the outside of the cell towards the center of the cell). [6]
Subsequent microtubule array assembly is, unlike that of the polarized spindle, interpolar. This is especially apparent in animal cells which must immediately, following mitotic spindle disassembly, establish the antiparallel bundle of microtubules known as the central spindle in order to regulate cytokinesis. [2]
After cytokinesis is complete, one of the two daughter cells inherits a remnant known as the midbody ring. [ 8 ] Activation of the cell-cycle kinase (e.g. Rho-kinases ) during telophase initiates constriction of the actomyosin ring by creating a groove that migrates in an inward motion.