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21 Cards in this Set
- Front
- Back
What essential question does electron transport and oxidative phosphorylation answer? |
-How cells oxidize NADH and FADH2 -Converting their reducing potential into ATP |
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Organization of the electron transport chain |
•Four protein complexes in theinner mitochondrial membrane
•A lipid soluble coenzyme (UQ,CoQ) and a water soluble protein (cyt c) shuttle between proteincomplexes •Electrons generally fall inenergy through the chain - from complexes I and II to complex IV |
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in the mitochondrion.... (1) Electron Transport: (2) Oxidative Phosphorylation: |
(1) electrons carried by reduced coenzymes generate a proton gradient across the inner mitochondrial membrane (2) the proton gradient runs 'downhill' to drive the synthesis of ATP |
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Fig. 20.29 Electron Transport and Oxidative Phosphorylation inhibitors: |
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What do uncouplers do? (1) of 4 |
1) uncouplers disrupt the tight coupling between electron transport and oxidative phosphorylation by dissipating the proton gradient |
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What do uncouplers do? (2) of 4 |
Chemical uncouplers are hydrophobic molecules with a dissociable proton |
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What do uncouplers do? (3) of 4 |
They shuttle back and forth across the membrane, carrying protons to dissipate the gradient. |
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what do uncouplers do? (4) of 4 |
some naturally occurring proteins are uncouplers: ex. UCP/ thermogenin help maintain body temperature |
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Uncouplers (chemical or proteinaceous) diagram: |
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Structures of common uncouplers: |
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What does ATP-ADP Translocase do? |
Translocase mediates the movement of ATP and ADP across the mitochondrial membrane |
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ATP must be transported out of the mitochondria: 1) What transports ADP in? 2) Why is ATP movement out favored? 3) Is ATP out and ADP in equivalent to a negative charge out? 4) How many H+ does every ATP transported out cost? 5) How many H+ does one ATP synthesis cost? 6) How many H+ does the synthesis and transport of one ATP cost? |
1) translocase 2) because the cytosol is "+" relative to the "-" matrix 3) yes, it is equivalent to an H+ going in 4) one H+ 5) three H+ 6) 3 H+ (synthesis) + 1H+ (transport) = 4 H+ (total) |
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Outward transport of ATP is favored by the membrane electrochemical potential (figure) |
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How many ATPs are made per electron pair through the chain? 1) Electron pair from NADH to Oxygen: 2) Electron pair from FADH2 to Oxygen: |
1) - ETC yields 10 H+ pumped out per electron pair from NADH to Oxygen - 4 H+ flow back into the matrix per ATP to cytosol - 10/4 = 2.5 for electrons entering as NADH 2) - For FADH2 about 6 H+ pumped per electron pair to oxygen - 6/4 = 1.5 for electrons entering as FADH2 |
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How are the electrons from cytosolic NADH fed into Electron transport? |
-shuttle systems result in electron movement without actually carrying NADH -Glycerophosphate shuttle: stores electrons in glycerol-3-P, which transfers electrons to FAD -Malate-Aspartate shuttle: uses malate to carry electrons across the membrane |
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the Glycerophosphate Shuttle: What does it do? + Figure |
- couples the cytosolic oxidation of NADH with mitochondrial reduction of [FAD] |
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The malate-aspartate shuttle: (Figure) |
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Net yield of ATP from Glucose Oxidation: glycerol-3-P shuttle used |
30 ATP per glucose |
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Net yield of ATP from Glucose Oxidation: Malate-Aspertate shuttle used |
32 ATP per glucose |
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Net yield of ATP from Glucose Oxidation: Bacteria |
No mitochondria - no extra H+ used to export ATP to cytosol: 10/3 = approximately 3 ATP / NADH 6/3 = approximately 2 ATP / FADH2 |
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Yield of ATP from Glucose Oxidation |
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