protoplasm

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protoplasm, term once used for the fundamental material of which all living things were thought to be composed. It was studied by a number of early scientists, especially by Félix Dujardin, J. E. Purkinje, M. J. S. Schultze, and Hugo von Mohl (who is credited with introducing the name), all working in the 19th cent. Many of the notions associated with the term have survived. Thus it is still accepted that all living organisms are made largely of the same classes of substances such as salts and organic molecules, that some of these are organized into structures large enough to be seen in the microscope and that water almost always is by far the most abundant material. However, the term is rarely used any more in a strictly scientific sense, although it survives in more literary usages. The unity of living matter is now most often described in terms of the cell as the unit of all living organisms (viruses, which are noncellular are at the border of life, being unable to reproduce independently outside living cells) and of the ubiquity of key biochemical molecules, especially nucleic acids and proteins.

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pro·to·plasm / ˈprōtəˌplazəm/ • n. Biol. the colorless material comprising the living part of a cell, including the cytoplasm, nucleus, and other organelles. DERIVATIVES: pro·to·plas·mic / ˌprōtəˈplazmik/ adj.

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protoplasm The complex, translucent, colourless, colloidal substance that occurs within each cell, including the cell membrane but excluding the large vacuoles, masses of secretions, ingested material, etc. It is differentiated into nucleoplasm (protoplasm in the nucleus) and cytoplasm (protoplasm in the rest of the cell).

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protoplasm A complex, translucent, colourless, colloidal substance within each cell, including the cell membrane, but excluding the large vacuoles, masses of secretions, ingested material, etc. In animals and plants it is differentiated into nucleoplasm (protoplasm in the nucleus) and cytoplasm (protoplasm in the rest of the cell).

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protoplasm The material comprising the living contents of a cell, i.e. all the substances in a cell except large vacuoles and material recently ingested or to be excreted. The term is no longer used; the material of the cell is now referred to as the cytoplasm, apart from the nucleoplasm inside the nucleus.

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protoplasm Living contents of a plant or animal cell. It includes both the nucleus and the cytoplasm of cells.

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protoplasm (proh-tŏ-plazm) n. the material of which living cells are made, which includes the cytoplasm and nucleus.
protoplasmic adj.