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27 Cards in this Set
- Front
- Back
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2 reasons why ETC creates energy for ATP synthesis:
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1. Establishes voltage gradient
2. Establishes proton gradient |
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What is the P/O ratio?
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A measure of phosphorylation efficiency; the # of phosphate bonds made per 1/2O2 -> H2O
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What is the P/O upper limit of:
-NADH -FADH2 |
NADH = 2.5
FADH2= 1.5 |
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What is the overall efficiency of converting NADH E into ATP?
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35%
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What is the chemiosmotic hypothesis?
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That ETC creates a H+ gradient across the inner mito membrane.
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What is the pH of the intermembrane space? Is this space pos or neg charged?
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1.4 units lower (more H+) than matrix; Pos charged w/ ref to matrix.
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What is the membrane potential established by PMF?
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.14 V
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What makes up the Proton Motive Force? (2 things)
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-Membrane potential contribution
-Chemical gradient contribution |
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What is Respiratory control index (RCI)?
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slope of [O2]vs time in State 3 vs State 4 mitochondria
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What info does RCI give?
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A measure of how tightly couple O2 consumption and ATP formation are.
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What state has a high RCI?
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Healthy mitochondria - protons don't leak back into the matrix and ETC pumps expected # of H+
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What does cyanide do?
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reversibly inhibits complex 4
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What inhibits ATP synthase?
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Oligomycin
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What uncouples the ETC from ATP synthase?
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DNP - dinitrophenol
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How does DNP work?
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It allows H+ to flow back into the mitochondria without driving ATP synthesis
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What are 3 other uncouplers?
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-Aspirin (proton shuttle)
-Valinomycin/gramicidin - replace H+ w/ K+ or Na+ |
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How does proton flow affect ATP Synthase?
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It causes conformation changes that remove H2O from ADP+Pi to form ATP
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What component of ATP synthase
-is in the matrix? -is in the membrane? |
Fo = in the membrane
F1 = in the matrix |
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How many protons are required for a conformational change?
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4
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When is uncoupling of PMF and ATP synthase good?
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When the energy is required for thermogenesis instead of ATP
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What tissue accomplishes this?
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Brown adipose tissue
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What is unique about the mitochondria in BAT?
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it contains an inner membrane ion transporter - UCP-1
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What is UCP1?
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Uncoupling protein 1 aka Thermogenin
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What does UCP1 do?
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Allows protons to flow back into matrix and makes HEAT instead of ATP.
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What is the RCI in BAT mitochondria?
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LOW
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What stimulates BAT thermogenesis?
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Obesity and overeating
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What is genetic obesity associated with?
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reduced BAT and lower thermogenesis.
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