Found 2 items, similar to Cell theory.
English → English (WordNet) Definition: cell theory cell theory n : (biology) the theory that cells form the fundamental structural and functional units of all living organisms; proposed in 1838 by Matthias Schleiden and by Theodor Schwann [syn: cell doctrine]
English → English (gcide) Definition: Cell theory Cell \Cell\, n. [OF. celle, fr. L. cella; akin to celare to hide, and E. hell, helm, conceal. Cf. Hall.] 1. A very small and close apartment, as in a prison or in a monastery or convent; the hut of a hermit. [1913 Webster] The heroic confessor in his cell. --Macaulay. [1913 Webster] 2. A small religious house attached to a monastery or convent. “Cells or dependent priories.” --Milman. [1913 Webster] 3. Any small cavity, or hollow place. [1913 Webster] 4. (Arch.) (a) The space between the ribs of a vaulted roof. (b) Same as Cella. [1913 Webster] 5. (Elec.) A jar of vessel, or a division of a compound vessel, for holding the exciting fluid of a battery. [1913 Webster] 6. (Biol.) One of the minute elementary structures, of which the greater part of the various tissues and organs of animals and plants are composed. [1913 Webster] Note: All cells have their origin in the primary cell from which the organism was developed. In the lowest animal and vegetable forms, one single cell constitutes the complete individual, such being called unicelluter orgamisms. A typical cell is composed of a semifluid mass of protoplasm, more or less granular, generally containing in its center a nucleus which in turn frequently contains one or more nucleoli, the whole being surrounded by a thin membrane, the cell wall. In some cells, as in those of blood, in the am[oe]ba, and in embryonic cells (both vegetable and animal), there is no restricting cell wall, while in some of the unicelluliar organisms the nucleus is wholly wanting. See Illust. of Bipolar. [1913 Webster] Air cell. See Air cell. Cell development (called also cell genesis, cell formation , and cytogenesis), the multiplication, of cells by a process of reproduction under the following common forms; segmentation or fission, gemmation or budding, karyokinesis, and endogenous multiplication. See Segmentation, Gemmation, etc. Cell theory. (Biol.) See Cellular theory, under Cellular. [1913 Webster] Cellular \Cel"lu*lar\ (s[e^]l"[u^]*l[~e]r; 135), a. [L. cellula a little cell: cf. F. cellulaire. See Cellule.] 1. Consisting of, or containing, cells; of or pertaining to a cell or cells. [1913 Webster] 2. porous; containing cavities. [PJC] 3. pertaining to or using a system of transmission of telephone signals by radio, in which areas are divided into geographical parts (cells), each of which is served by a transmitter whose range is limited to that region, thus permitting a single transmission frequency to be used simulataneously in different parts of the same area. Cellular telephones are typically small and battery powered, allowing a subscriber with such a telephone to carry the telephone in a pocket or purse, over the entire area served, and to be contacted by a single telephone number. The system became widespread and popular in the 1980's and 1990's; as, cellular telephones sometimes lose their link unpredictably. [PJC] Cellular plants, Cellular cryptogams (Bot.), those flowerless plants which have no ducts or fiber in their tissue, as mosses, fungi, lichens, and alg[ae]. Cellular theory, or Cell theory (Biol.), a theory, according to which the essential element of every tissue, either vegetable or animal, is a cell; the whole series of cells having been formed from the development of the germ cell and by differentiation converted into tissues and organs which, both in plants and animals, are to be considered as a mass of minute cells communicating with each other. Cellular tissue. (a) (Anat.) See conjunctive tissue under Conjunctive. (b) (Bot.) Tissue composed entirely of parenchyma, and having no woody fiber or ducts. [1913 Webster]