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Metaphase (from Ancient Greek μετα- beyond, above, transcending and from Ancient Greek φάσις (phásis) 'appearance') is a stage of mitosis in the eukaryotic cell cycle in which chromosomes are at their second-most condensed and coiled stage (they are at their most condensed in anaphase). [1]
Schematic karyogram of the human chromosomes, showing their usual state in the G 0 and G 1 phase of the cell cycle. At top center it also shows the chromosome 3 pair after having undergone DNA synthesis, occurring in the S phase (annotated as S) of the cell cycle. This interval includes the G 2 phase and metaphase (annotated as "Meta.").
Cell division by mitosis is an equational division which gives rise to genetically identical cells in which the total number of chromosomes is maintained. [1] Mitosis is preceded by the S phase of interphase (during which DNA replication occurs) and is followed by telophase and cytokinesis, which divide the cytoplasm, organelles, and cell ...
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.
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.
Meiosis II-nondisjunction may also result in aneuploidy syndromes, but only to a much smaller extent than do segregation failures in meiosis I. [6] Nondisjunction of sister chromatids during mitosis: Left: Metaphase of mitosis. Chromosome line up in the middle plane, the mitotic spindle forms and the kinetochores of sister chromatids attach to ...
Four phases of mitosis: prophase, metaphase, anaphase, and telophase: Prophase: Chromatin into chromosomes, the nuclear envelope breaks down, chromosomes attach to spindle fibers by their centromeres. Metaphase: Chromosomes line up along the metaphase plate (center of the cell). Anaphase: Sister chromatids are pulled to opposite poles of the cell.
Mitosis consists of two independent processes: the intra-chromosomal and the extra-chromosomal (formation of spindle) changes both of these being in total coordination of each other. This cell as seen under immunofluorescence contains four centrosomes, two at each end, with their own spindle fibers attaching to chromosomes at the metaphase plate.