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The different stages of mitosis altogether define the mitotic phase (M phase) of a cell cycle—the division of the mother cell into two daughter cells genetically identical to each other. [ 3 ] The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next.
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.
During this time, necessary mitotic proteins are produced and the cell is once more subjected to regulatory mechanisms to ensure proper status for entry into the proliferative Mitotic (M) phase. Multiple mechanistic checkpoints are involved in this transition from G2 to M, with a common uniting factor of cyclin-Cdk activity.
Mitosis in an animal cell (phases ordered counter-clockwise), with G 1 labeled at left. The G 1 phase, gap 1 phase, or growth 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. In this part of interphase, the cell synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis.
During G 2, the cell undergoes the final stages of growth before it enters the M phase, where spindles are synthesized. The M phase can be either mitosis or meiosis depending on the type of cell. Germ cells, or gametes, undergo meiosis, while somatic cells will undergo mitosis. After the cell proceeds successfully through the M phase, it may ...
Mitotic exit is an important transition point that signifies the end of mitosis and the onset of new G1 phase for a cell, and the cell needs to rely on specific control mechanisms to ensure that once it exits mitosis, it never returns to mitosis until it has gone through G1, S, and G2 phases and passed all the necessary checkpoints.
Mitosis includes four phases: prophase, metaphase, anaphase, and telophase. Prophase is the initial phase when spindle fibers appear that function to move the chromosomes toward opposite poles. This spindle apparatus consists of microtubules, microfilaments and a complex network of various proteins.
Maturation-promoting factor (abbreviated MPF, also called mitosis-promoting factor or M-Phase-promoting factor) is the cyclin–Cdk complex that was discovered first in frog eggs. [ 1 ] [ 2 ] It stimulates the mitotic and meiotic phases of the cell cycle .