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9 Cards in this Set
- Front
- Back
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Def: The process by which a signal on a cell's surface is converted into a specific cellular response. (202)
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Signal Transduction Pathway
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Def: Messenger molecules that only travel a short distance. (202)
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Local regulators
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What are the three types of cell communication in animals, and how do they communicate (203)
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a) paracrine signaling - a secreting cell acts on nearby target cell by discharging molecules of a local regulator into the extracellular fluid.
b)synaptic signaling - a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell. c)hormonal signaling - specialized endocrine cells secrete hormones into body fluids, often the blood. Hormones may reach all the body cells. |
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Def: A plasma membrane receptor that works with the help of a G protein. (206)
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G-protein-linked receptors
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Name 4 steps that g-protein receptors undergo. (206)
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1)When GDP(used GTOP) is bound to the G protein, it is inactive.
2)When the appropriate signal molecule binds to the extracellular side of the receptor, the receptor changes shape, and binds to a g-protein, which consequently activates. 3) The activated G protein dissociates from the receptor, then binds to an enzyme to alter its activity. 4) Right after, the G-protein uses up the GTP, then returns to its original position. |
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Def: an enzyme that catalyzes the transfer of phosphate groups. (207)
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Kinase.
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Name the 3 steps in receptor tyrosine kinases signal transduction. (207)
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1)The binding of a signal molecule causes two receptor polypeptides to associate closely with each other, forming a dimer. (<dimerization!)
2) Dimerizatino activates the tyrosine-kinase region of each polypeptide. Each tyrosine-kinase adds a phosphate from an ATP molecule to a tyrosine on the tail o the other polypeptide. 3)It is then recognized by specific relay proteins. Each protein binds to a specific phosphorylated tyrosine, undergoing activation. |
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Describe the structure of a receptor tyrosine kinase. (207)
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they exist as individual polypeptides, with an extracellular binding site, an alpha helix spanning the membrane, and an intracellular tail containing muliple tyrosines.
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Def: When a series of different molecules in a pathway are phosphorylated in turn, each molecule adding a phosphate group to the next one in line. (209)
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Phosphorylation cascade.
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