Phases
The
cell cycle consists of four distinct phases: G1 phase, S phase
(synthesis), G2 phase (collectively known as interphase) and M phase
(mitosis). M phase is itself composed of two tightly coupled processes:
mitosis, in which the cell's chromosomes are divided between the two
sister cells, and cytokinesis, in which the cell's cytoplasm divides in
half forming distinct cells. Activation of
each phase is dependent on the proper progression and completion of the
previous one. Cells that have temporarily or reversibly stopped dividing
are said to have entered a state of quiescence called G0 phase.
After cell division, each of the daughter cells begin the interphase of a new cycle. Although the various stages of interphase are not usually morphologically distinguishable, each phase of the cell cycle has a distinct set of specialized biochemical processes that prepare the cell for initiation of cell division.
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