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Article: Membrane Proteins
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- Biology
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CopyrightCOPYRIGHT 2002 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Membrane Proteins
Cells and their
organelles
are
aqueous
compartments bounded by thin membranes. The core of these membranes is a film of specialized
lipids
, two molecules thick. Attached to and embedded in this lipid
bilayer
are numerous proteins, each specialized to carry out a different function. Thus, each membrane has its own team of proteins. A typical membrane might be composed half of lipid and half of protein. However, this varies widely. For example, the envelopes of some viruses employ only a few protein species to gain entry into cells and later mediate the exit of new virus particles. In contrast, busy membranes are crowded with hundreds of different proteins; each ...