cell division
 細胞分裂


 cell division 名詞
 細胞分裂


 Nu·cle·us n.; pl. E. Nucleuses L. Nuclei
 1. A kernel; hence, a central mass or point about which matter is gathered, or to which accretion is made; the central or material portion; -- used both literally and figuratively.
    It must contain within itself a nucleus of truth.   --I. Taylor.
 2. Astron. The body or the head of a comet.
 3. Bot. (a) An incipient ovule of soft cellular tissue. (b) A whole seed, as contained within the seed coats.
 4. Biol. A body, usually spheroidal, in a eukaryotic cell, distinguished from the surrounding protoplasm by a difference in refrangibility and in behavior towards chemical reagents, which contains the chromosomal genetic material, including the chromosomal DNA.  It is more or less protoplasmic, and consists of a clear fluid (achromatin) through which extends a network of fibers (chromatin) in which may be suspended a second rounded body, the nucleolus (see Nucleoplasm). See Cell division, under Division.
 Note: ☞ The nucleus is sometimes termed the endoplast or endoblast, and in the protozoa is supposed to be concerned in the female part of the reproductive process. See Karyokinesis.
 5. Zool. (a) The tip, or earliest part, of a univalve or bivalve shell. (b) The central part around which additional growths are added, as of an operculum. (c) A visceral mass, containing the stomach and other organs, in Tunicata and some mollusks.

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 par·ent n.
 1. One who begets, or brings forth, offspring; a father or a mother.
    Children, obey your parents in the Lord.   --Eph. vi. 1.
 2. That which produces; cause; source; author; begetter; as, idleness is the parent of vice.
    Regular industry is the parent of sobriety.   --Channing.
 Parent cell. Biol. See Mother cell, under Mother, also Cytula.
 Parent nucleus Biol., a nucleus which, in cell division, divides, and gives rise to two or more daughter nuclei.  See Karyokinesis, and Cell division, under Division.

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 Daugh·ter n.; pl. Daughters obs. pl. Daughtren
 1. The female offspring of the human species; a female child of any age; -- applied also to the lower animals.
 2. A female descendant; a woman.
    This woman, being a daughter of Abraham.   --Luke xiii. 16.
    Dinah, the daughter of Leah, which she bare unto Jacob, went out to see the daughter of the land.   --Gen. xxxiv. 1.
 3. A son's wife; a daughter-in-law.
    And Naomi said, Turn again, my daughters.   --Ruth. i. 11.
 4. A term of address indicating parental interest.
    Daughter, be of good comfort.   --Matt. ix. 22.
 Daughter cell Biol., one of the cells formed by cell division. See Cell division, under Division.

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 Di·vi·sion n.
 1. The act or process of diving anything into parts, or the state of being so divided; separation.
    I was overlooked in the division of the spoil.   --Gibbon.
 2. That which divides or keeps apart; a partition.
 3. The portion separated by the divining of a mass or body; a distinct segment or section.
    Communities and divisions of men.   --Addison.
 4. Disunion; difference in opinion or feeling; discord; variance; alienation.
    There was a division among the people.   --John vii. 43.
 5. Difference of condition; state of distinction; distinction; contrast.
    I will put a division between my people and thy people.   --Ex. viii. 23.
 6. Separation of the members of a deliberative body, esp. of the Houses of Parliament, to ascertain the vote.
    The motion passed without a division.   --Macaulay.
 7. Math. The process of finding how many times one number or quantity is contained in another; the reverse of multiplication; also, the rule by which the operation is performed.
 8. Logic The separation of a genus into its constituent species.
 9. Mil. (a) Two or more brigades under the command of a general officer. (b) Two companies of infantry maneuvering as one subdivision of a battalion. (c) One of the larger districts into which a country is divided for administering military affairs.
 10. Naut. One of the groups into which a fleet is divided.
 11. Mus. A course of notes so running into each other as to form one series or chain, to be sung in one breath to one syllable.
 12. Rhet. The distribution of a discourse into parts; a part so distinguished.
 13. Biol. A grade or rank in classification; a portion of a tribe or of a class; or, in some recent authorities, equivalent to a subkingdom.
 Cell division Biol., a method of cell increase, in which new cells are formed by the division of the parent cell. In this process, the cell nucleus undergoes peculiar differentiations and changes, as shown in the figure (see also Karyokinesis). At the same time the protoplasm of the cell becomes gradually constricted by a furrow transverse to the long axis of the nuclear spindle, followed, on the completion of the division of the nucleus, by a separation of the cell contents into two masses, called the daughter cells.
 Long division Math., the process of division when the operations are mostly written down.
 Short division Math., the process of division when the operations are mentally performed and only the results written down; -- used principally when the divisor is not greater than ten or twelve.
 Syn: -- compartment; section; share; allotment; distribution; separation; partition; disjunction; disconnection; difference; variance; discord; disunion.

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 En·dog·e·nous a.
 1. Bot. Increasing by internal growth and elongation at the summit, instead of externally, and having no distinction of pith, wood, and bark, as the rattan, the palm, the cornstalk.
 2. Biol. Originating from within; increasing by internal growth.
 Endogenous multiplication Biol., a method of cell formation, seen in cells having a cell wall. The nucleus and protoplasm divide into two distinct masses; these in turn become divided and subdivided, each division becoming a new cell, until finally the original cell wall is ruptured and the new cells are liberated (see Segmentation, and Illust. of Cell Division, under Division). This mode of growth is characteristic of many forms of cells, both animal and vegetable.

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 Fis·sion n.
 1. A cleaving, splitting, or breaking up into parts.
 2. Biol. A method of asexual reproduction among the lowest (unicellular) organisms by means of a process of self-division, consisting of gradual division or cleavage of the into two parts, each of which then becomes a separate and independent organisms; as when a cell in an animal or plant, or its germ, undergoes a spontaneous division, and the parts again subdivide. See Segmentation, and Cell division, under Division.
 3. Zool. A process by which certain coral polyps, echinoderms, annelids, etc., spontaneously subdivide, each individual thus forming two or more new ones. See Strobilation.

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 cell division
      n : the process in reproduction and growth by which a cell
          divides to form daughter cells [syn: cellular division]