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13 Cards in this Set
- Front
- Back
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1. What is coenzyme Q?
What is special about it? |
1. Not a protein or protein bound
2. Lipid-soluble 3. Forms part of proton pump for complexes I and II **Only part of e- transport chain that is not protein |
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2. What does coenzyme Q do?
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Picks up e- from complex I and donates them to complex III
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3. What is the energy level of complex II?
Does donation of e- from succinic dehydrogenase to CoQ pump protons? What is result? |
Same as CoQ
No ATP yield from FADH2 oxidation is lower than yield from NADH |
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4. Which cytochromes does complex IV (cytochrome oxidase) contain?
What else does it contain? |
Cytochromes a and a3
Copper (Cu) **Has a binding site of O2 |
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5. Where is the ATP synthase?
How does it produce ATP? |
Spans the inner mitochondrial membrane
Conformational changes in synthase causes synthesis of ATP (coupled to oxidative phophorlyation) |
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6. Approximately how many ATPs come from NADH?
FADH2? |
3 per NADH
2 per FAD (e- miss complex I so get less energy) |
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7. How does increased ATP hydrolysis affect ATP synthase?
What does this in turn affect? |
Increase formation of ATP by ATP synthaase
Decrease proton gradients b/c have increased flux of protons through ATP synthase pores Since proton gradient decreased, e- flow will increase and rate of NADH and FADH2 oxidation will increase |
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8. What are chemical uncouplers?
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Lipid-soluble compounds that can pick up a proton from intermembrane space and diffuse through inner membrane carrying proton back into matrix
**doesn't go through ATP synthase **body compensates by increasing metabolism (more NADH and FADH2) |
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9. What does uncoupling in adipose tissue result in?
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Release of energy as heat
**Brown adipose tissue in infants have uncoupling protein and when baby is cold, protein will be activated |
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10. What two major messengers feed information on the rate of ATP utilization back to the TCA cycle?
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ATP/ADP + P1 levels
(phosphorylated state of ATP) NADH/NAD+ ratio (reduction state of NAD+) |
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11. How do NADH/NAD+ ratios affect ATP synthesis?
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High NADH levels, slow down ATP production
**Most of form is NAD+ in cell so accumlaiton of NADH is good regulator b/c cell is sensitive to NADH changes (most sensitive indicator in ATP mitochondria |
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12. What are the major sites of feedback regulation in the TCA cycle?
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1. Isocitrate dehydrogenase
-allosterically activated by ADP -inhibited by NADH 2. α-ketoglutarate dehydrogenase -inhibited by NADH and succinyl CoA 3. Malate dehydrgenase/citrate synthase -decrease oxaloacetate below km of citrate synthase if increase NADH/NAD+ 4. Pyruvate dehydrogenase (not technically part of TCA cycle) -pyruvate to acetyl CoA -inhibition by acetyl CoA, NADH, phosphorylation |
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13. What does Ca+ do?
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"Feed-forward" mechanism
Activates α-ketoglutarate dehydrogenase, isocitrate dehydrogenase, and pyruvate dehydrogenase |
