mitosis


mitosis
mitotic /muy tot"ik/, adj.mitotically, adv.
/muy toh"sis/, n. Cell Biol.
the usual method of cell division, characterized typically by the resolving of the chromatin of the nucleus into a threadlike form, which condenses into chromosomes, each of which separates longitudinally into two parts, one part of each chromosome being retained in each of two new cells resulting from the original cell. Cf. meiosis.
[1885-90; < Gk mít(os) a thread + -OSIS]

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Cell division, or reproduction, in which a cell gives rise to two genetically identical daughter cells.

Strictly applied, the term describes the duplication and distribution of chromosomes. Prior to mitosis, each chromosome is replicated, producing two strands (chromatids) attached at a centromere. During mitosis, the membrane around the cell's nucleus dissolves and the chromatids of each chromosome are separated and pulled to each end of the cell. As the nuclear membrane re-forms around each set of chromosomes, the cytoplasm of the parent cell begins to divide to form two daughter cells. Following mitosis, the cell membrane pinches in to separate the daughter cells. Mitosis is essential to life because it provides new cells for growth and for replacement of worn-out cells. It may take minutes or hours, depending on the kind of cells and species of organisms. It is influenced by time of day, temperature, and chemicals. See also centromere, meiosis.

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 a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells. Strictly applied, the term mitosis is used to describe the duplication and distribution of chromosomes (chromosome), the structures that carry the genetic information.

      A brief treatment of mitosis follows. For a full treatment, see growth: In cells (growth); cell: Mitosis and cytokinesis (cell).

      Prior to the onset of mitosis, the chromosomes have replicated and the proteins that will form the mitotic spindle have been synthesized. Mitosis begins at prophase with the thickening and coiling of the chromosomes. The nucleolus, a rounded structure, shrinks and disappears. The end of prophase is marked by the beginning of the organization of a group of fibres to form a spindle and the disintegration of the nuclear membrane.

 The chromosomes, each of which is a double structure consisting of duplicate chromatids, line up along the midline of the cell at metaphase. In anaphase each chromatid pair separates into two identical chromosomes that are pulled to opposite ends of the cell by the spindle fibres. During telophase, the chromosomes begin to decondense, the spindle breaks down, and the nuclear membranes and nucleoli re-form. The cytoplasm of the mother cell divides to form two daughter cells, each containing the same number and kind of chromosomes as the mother cell. The stage, or phase, after the completion of mitosis is called interphase.

      Mitosis is absolutely essential to life because it provides new cells for growth and for replacement of worn-out cells. Mitosis may take minutes or hours, depending upon the kind of cells and species of organisms. It is influenced by time of day, temperature, and chemicals.

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Universalium. 2010.

Look at other dictionaries:

  • mitosis — f. citol. Tipo de división celular en la que a partir de una célula se forman dos células hijas con la misma dotación cromosómica que la progenitora. La mitosis comprende cuatro fases: profase, metafase, anafase y telofase. En la profase… …   Diccionario médico

  • mitosis — (plural mitosis) sustantivo femenino 1. Área: biología Proceso de reproducción celular en el que mediante la división de la célula madre se originan dos células hijas con el mismo número de cromosomas e igual información genética …   Diccionario Salamanca de la Lengua Española

  • Mitosis — Mi*to sis, n. [NL., fr. Gr. ? a thread.] (Biol.) See {Karyokinesis}. [1913 Webster] …   The Collaborative International Dictionary of English

  • mitosis — mitosis. См. непрямое деление. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • mitosis — (n.) 1887, coined in German from Gk. mitos warp thread (see MITRE (Cf. mitre)) + Mod.L. osis act, process. Term introduced by German anatomist Walther Fleming (1843 1905) in 1882. So called because chromatin of the cell nucleus appears as long… …   Etymology dictionary

  • mitosis — (Del gr. μιτοῦν, tejer, y sis). f. Biol. División de la célula en la que, previa duplicación del material genético, cada célula hija recibe una dotación completa de cromosomas …   Diccionario de la lengua española

  • mitosis — ► NOUN (pl. mitoses) Biology ▪ a type of cell division in which daughter cells have the same number and kind of chromosomes as the parent nucleus. Compare with MEIOSIS(Cf. ↑meiotic). ORIGIN from Greek mitos thread …   English terms dictionary

  • mitosis — [mī tō′sis, mitō′sis] n. pl. mitoses [mī tō′sēz΄, mi tō′sēz΄] [ModL < Gr mitos, thread + OSIS] Biol. the indirect and more common method of nuclear division of cells, consisting typically of prophase, metaphase, anaphase, and telophase: the… …   English World dictionary

  • Mitosis — Not to be confused with meiosis, miosis, or myositis. Mitosis divides the chromosomes …   Wikipedia

  • Mitosis — Micrografía de una célula mitótica pulmonar de tritón. Cromosomas homólogos en mitosis (arriba) y me …   Wikipedia Español


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