New insights into centromere structure

Researchers led by Osaka University used cryogenic electron microscopy to analyze the atomic structure of the centromeric region of the chromosome, essential for cell division. A protein called CENP-A marks the centromere; ...

Rice breeding breakthrough could feed billions

An international team has succeeded in propagating a commercial hybrid rice strain as a clone through seeds with 95 percent efficiency. This could lower the cost of hybrid rice seed, making high-yielding, disease resistant ...

The signals that make cells self-destruct

Most human hearts look nearly identical—muscle cells in the same places, blood vessel structures in the same orientations. Organs such as hearts or stomachs look alike and function the same across individual organisms in ...

Cancer origin identified through cell 'surgery'

Research from the University of Warwick sheds new light on a key cause of cancer formation during cell division (or mitosis), and points towards potential solutions for preventing it from occurring.

Scientists gain new insights into the mechanisms of cell division

Mitosis is the process by which the genetic information encoded on chromosomes is equally distributed to two daughter cells, a fundamental feature of all life on earth. Scientists led by Alexander Dammermann at the Max Perutz ...

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Mitosis

Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly equal shares of these cellular components. Mitosis and cytokinesis together define the mitotic (M) phase of the cell cycle—the division of the mother cell into two daughter cells, genetically identical to each other and to their parent cell. This accounts for approximately 10% of the cell cycle.

Mitosis occurs only in eukaryotic cells and the process varies in different species. For example, animals undergo an "open" mitosis, where the nuclear envelope breaks down before the chromosomes separate, while fungi such as Aspergillus nidulans and Saccharomyces cerevisiae (yeast) undergo a "closed" mitosis, where chromosomes divide within an intact cell nucleus. Prokaryotic cells, which lack a nucleus, divide by a process called binary fission.

The process of mitosis is fast and highly complex. The sequence of events is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are interphase, prophase, prometaphase, metaphase, anaphase and telophase. During mitosis the pairs of chromatids condense and attach to fibers that pull the sister chromatids to opposite sides of the cell. The cell then divides in cytokinesis, to produce two identical daughter cells which are still diploid cells.

Because cytokinesis usually occurs in conjunction with mitosis, "mitosis" is often used interchangeably with "mitotic phase". However, there are many cells where mitosis and cytokinesis occur separately, forming single cells with multiple nuclei. This occurs most notably among the fungi and slime moulds, but is found in various groups. Even in animals, cytokinesis and mitosis may occur independently, for instance during certain stages of fruit fly embryonic development. Errors in mitosis can either kill a cell through apoptosis or cause mutations that may lead to cancer.

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