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| Cytoplasm |
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| The term cytoplasm can be used to describe the matrix of a cell found between its plasma membrane and the nucleus. It encloses various cell organelles and inclusions. |
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| The cytoplasm is a semi viscous jelly-like substance. It consists of an aqueous, almost transparent structureless ground substance called hyaloplasm or cytosol. Nearly 90% of cytosol is water. It also contains the various biomolecules, both micromolecules and macromolecules. All those substances occur in the cytoplasm in a state of solution. |
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| The cytoplasm may be found in a non-viscous state called sol state or in a viscous state called gel state. It keeps fluctuating between the sol state and the gel state. |
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| The autonomic movement of the cytosol is called cytoplasmic streaming or cyclosis. In some plant cells and protozoans, cyclosis occurs regularly. These cells are large and as such diffusion will not be sufficient to distribute the materials. The cytoplasmic streaming serves to overcome this problem. |
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| fig. 16.4 - Paramecium |
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| In Paramecium the streaming movement of cytoplasm carries the food vacuole in a specific path. While the food vacuole is in movement, most of the food material gets digested. |
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| Cytoplasm serves the following functions |
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 It is the seat of all metabolic and bio-chemical processes taking place in a cell. |
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 It is involved in the storage of raw materials or reserve food required by the cell. |
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 It brings about exchange of materials between the cell organelles. |
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 It exchanges materials with the surrounding environment such as extra cellular fluid. |
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