cell notes

cell notes - Cell biology book notes CH 15 Extracellular...

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Cell biology book notes CH 15 Extracellular Signal Molecules Bind to Specific Receptors Target cell responds by means of a receptor----binds to signal molecule then initiates a response in the target cell. The extracellular signal molecules act at very low concentrations----receptors bind with high affinity.----receptors are normally transmembrane proteins on target protein-bind a ligan and become activated to generate intracellular signals that alter cell behavior. Two types of receptors: Extracellular: hydrophilic signal molecule Intracellular: small hydrophobic signal molecule Extracellular Signal Molecules Can Act over Either Short or Long distances Contact-dependent signaling: important during development of immune responses. Can operate over large distances. Most signals are mediated through cellular secretions into the ECF (extracellular fluid). Local mediators: affect only cells in the local environment of the signaling cells---- process called paracrine signaling
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cell notes - Cell biology book notes CH 15 Extracellular...

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