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/sel/ Noun, pl. cells 1. The functional basic unit of life ( 2. The smallest structural and functional unit of an organism, typically microscopic and consisting of cytoplasm and a nucleus enclosed in a membrane. Microscopic organisms typically consist of a single cell, which is either eukaryotic or prokaryotic. ( 3. The fundamental unit of all living tissue. Eukaryotic cells consist of a nucleus, cytoplasm, and organelles surrounded by a plasma membrane. Within the nucleus are the nucleolus (containing ribonucleic acid) and the chromatin (containing protein and deoxyribonucleic acid), which form chromosomes, wherein are located the determinants of inherited characteristics. Organelles within the cytoplasm include the endoplasmic reticulum, ribosomes, Golgi apparatus, mitochondria, lysosomes, and centrosome. Prokaryotic cells are much smaller and simpler than eukaryocytic cells, even lacking a nucleus. The specialized nature of body tissue reflects the specialized structure and function of its constituent cells. (Mosby’s Medical Dictionary, 8th edition. © 2009, Elsevier.) Word origin: From Old English *cella (attested in inflected forms), from Latin cella (“chamber, small room, compartment”), later reinforced by Anglo-Norman cel, sele, Old French...

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Cell biology

Noun 1. Branch of biology that deals with the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell. 2. A scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level. (   See also cytology. Word origin: formerly...

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Cell Theory

1. Cell theory states that: All known living things are made up of cells. The cell is structural & functional unit of all living things. All cells come from pre-existing cells by division, (i.e. Spontaneous generation does not occur). Cells contain hereditary information which is passed from cell to cell during cell division. All cells are basically the same in chemical composition. All energy Flow (metabolism & biochemistry) of life occurs within cells. ( 2. 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 ( 3. A scientific theory that describes the properties of cells, the basic unit of structure in every living thing....

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Cell wall

Noun, pl. cell walls 1. A membrane of the cell that forms external to the cell membrane whose main role is to give cells rigidity, strength and protection against mechanical stress. It is found in cells of plants, bacteria, archaea, fungi, and algae. Animals and most protists do not have cell walls. ( 2. (Cytology) A thick, fairly rigid, layer formed around individual cells of bacteria, Archaea, fungi, plants, and algae (but not animals and other protists which generally have cell membranes without cell walls). The cell wall is external to the cell membrane and serves a structural function helping the cell maintain its shape and protecting the cell from damage. ( 3. The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, in addition to acting as a filtering mechanism. ( 4. The outermost layer of a Cell in most Plants; Bacteria; Fungi; and ALGAE. The Cell wall is usually a rigid structure that lies external to the Cell Membrane, and provides a protective barrier against physical or chemical agents....

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/ˈselyələr/ Adjective 1. Of, relating to, consisting of, or resembling a cell or cells. ( 2. Derived from, or consisting of cell(s). ( 3. Having numerous compartments or cells. ( Word origin: NL cellulāris, equiv. to cellul(a) live cell (L: little...

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