Lecture 7-07

Lecture 7-07 - L312/Spring 2007 Lecture 7 Drummond oday:...

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L312/Spring 2007 Lecture 7 Drummond Today: Focus on Chapter 16, 542-557: Transmembrane signaling involving G-proteins Next Thursday, Ch. 16 557-567. ass news: Exam is coming in 10 days! Study questions part II to be posted after the next lecture This week’s content IS covered on first exam (but not next Tuesday). Timing for review sessions will be decided on in class Thursday and posted later Andrian will post keys starting today--my fault they haven’t gotten up view key points: a. Considered three classes of gated ion channels: by voltage, ligand and mechanical stress b. Three conformations of voltage gated sodium channel control directional movement (closed but ready, open and sodium passes, then inactivated). c. K + flux (leak) across a membrane without counterion (e.g. Cl - ) causes a voltage (voltage = separation of charge; resting in many nerve cells ~ -60 mV) flow is “down” a concentration gradient (favorable) d. Depolarization signal (e.g. mechanical stress in hearing) causes slight rise in potential (e.g. to -40 mV) that triggers voltage gated sodium channel e. Signals are propagated directionally without loss of intensity (how?) system recovery is by Na/K exchanger (ATP driven) restoring concentration gradients
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This note was uploaded on 07/02/2011 for the course BIO-L 312 taught by Professor Drummond during the Fall '07 term at Indiana.

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Lecture 7-07 - L312/Spring 2007 Lecture 7 Drummond oday:...

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