The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Cytoplasm (also called protoplasm) is the fluid or semi-solid medium enclosed by the outer cellular or plasma membrane and outside the cell nucleus. Basically an aqueous solution rich in proteins, carbohydrates, lipids, nucleic acids, and salts, the cytoplasm is the environment within which all the reactions of cellular metabolism take place. In many cells, the cytoplasm is in constant motion, transporting materials from one place to another. One of the best places to see this is in slime molds, protozoa, and certain algal species, where an ordinary light microscope shows streams of cytoplasm coursing through cell interiors.
One of the most interesting features of cytoplasm is its ability to change from a liquid (or sol) state to semisolid (or gel) state. This transition is brought about by polymerization of microtubules, microfilaments and other elements of the protoplasm cytoskeleton. Contraction of these cytoskeletal elements generates hydrostatic pressure that causes streaming of the liquid phase of the cytoplasm. Movement of molecular motors such as dyein along the elements of the cytoskeleton also helps move materials through the cytoplasm.
In addition to dissolved compounds, the cytoplasm also contains a wide variety of organelles. Among the prominent membrane-bound cytoplasmic organelles are mitochondria, chloroplasts, the endoplasmic reticulum, and the Golgi apparatus. Some macromolecular structures, such as ribosomes, centrioles, microtubules, and microfilaments, could also be considered cytoplasmic organelles.