Chapter 9
Cell Communication
By Boundless
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Cellular communication ensures regulation of biological processes within various environments from single-celled to multicellular organisms.
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The major types of signaling mechanisms that occur in multicellular organisms are paracrine, endocrine, autocrine, and direct signaling.
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Receptors, either intracellular or cell-surface, bind to specific ligands, which activate numerous cellular processes.
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Signaling molecules are necessary for the coordination of cellular responses by serving as ligands and binding to cell receptors.
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Ligand binding to cell-surface receptors activates the receptor's intracellular components setting off a signaling pathway or cascade.
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Signaling pathway induction activates a sequence of enzymatic modifications that are recognized in turn by the next component downstream.
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Signal cascades convey signals to the cell through the phosphorylation of molecules by kinases.
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Gene expression, vital for cells to function properly, is the process of turning on a gene to produce RNA and protein.
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The rush of adrenaline that leads to greater glucose availability is an example of an increase in metabolism.
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Cell growth is promoted by ligands known as growth factors.
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When a cell is damaged, unnecessary, or dangerous to an organism, a cell can initiate the mechanism for cell death known as apoptosis.