| slovo | definícia |
cell theory
(encz) | cell theory, n: |
Cell theory
(gcide) | 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.
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The heroic confessor in his cell. --Macaulay.
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2. A small religious house attached to a monastery or
convent. "Cells or dependent priories." --Milman.
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3. Any small cavity, or hollow place.
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4. (Arch.)
(a) The space between the ribs of a vaulted roof.
(b) Same as Cella.
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5. (Elec.) A jar of vessel, or a division of a compound
vessel, for holding the exciting fluid of a battery.
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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.
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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.
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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.
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Cell theory
(gcide) | 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.
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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.
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cell theory
(wn) | cell theory
n 1: (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 theory, cell doctrine] |
| | podobné slovo | definícia |
cell theory
(encz) | cell theory, n: |
cell theory
(wn) | cell theory
n 1: (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 theory, cell doctrine] |
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