341lecture22oct30sakai

341lecture22oct30sakai - Cell Biology 341 Friday, October...

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Cell Biology 341 Friday, October 30, 2009 Today: A ligand-gated channel that opens in response to binding acetylcholine Begin chapter 12 on how proteins are sorted to the correct organelles Exam Wednesday, Nov 4, covers chapters 7, 10 and 11, beginning on October 5 Office hours: Tuesday 10 am-noon, 1-2 pm Bring #2 pencils Last lecture: the power of passive transport An action potential travels toward a nerve terminal as voltage-gated Na + channels open, allowing Na + to enter the cell The potential shifts to a positive value, but the inactivation of the Na + channels and the opening of voltage- gated K + channels quickly restores the (-) potential When the action potential reaches the terminal, voltage-gated Ca ++ channels open, triggering exocytosis of acetylcholine
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The nicotinic acetylcholine receptor is a ligand-gated channel in the plasma membrane of skeletal muscle cells The channel opens when acetylcholine (the neurotransmitter) binds to a specific site on the outside of the α subunits of the receptor The amphipathic helices of the pore rotate, moving hydrophobic groups out of the channel Figure 11-38 Passive transport K + will have little effect on the membrane potential, but Na + will create a local depolarization
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The acetylcholine receptor
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This note was uploaded on 12/05/2009 for the course BIO 341 taught by Professor Noris during the Fall '09 term at Rhode Island.

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341lecture22oct30sakai - Cell Biology 341 Friday, October...

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