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22 Cards in this Set
- Front
- Back
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Main function of TCA
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provide
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where does TCA occur?
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mitochondrial matrix
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what enzyme converts pyruvate to acetyl coA
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Pyruvate Dehydrogenase Complex
1) pyruvate Dehydrogenase (E1) 2) Dihydrolipoyl transacetylase (E2) 3) Dihydrolypoyl DH (E3) |
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How many NADH and FADH are produced?
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3 NADH
2 FADH2 1 GTP |
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How many ATP per circle of TCA?
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12
NADH = 3 ATP FADH2 = 2 ATP |
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What inhibits PDH?
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1) Protein Kinase stimulated by ATP, NADH and Acetyl CoA
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What is the inactivated form of PDH?
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cAMP independent PK is P --> E1 inhibited
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Activated form of PDH
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Phosphoprotein phosphatase activates and dephos occurs of PDH
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What activates the Protein kinase?
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- increased ATP
- increased NAD+ and CoA inhibits |
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How much ATP from 1 pyruvate to 1 acetyl CoA
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3 ATP = NADH
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effect of citrate on glycolysis
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inhibition of PFK1 so inhibition of glycolysis
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Regulatory steps of TCA
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1) Citrate Synthase
2) Isocitrate DH 3) α KG DH 4) Succinate DH |
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What would lower NAD+ levels do to Isocitrate DH?
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inhibit or slow it down
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increased NADH on α KGDH?
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inhibit or slow it down
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Where are 2 CO2 molecules released in TCA?
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Isocitrate DH
α KG DH |
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What bond is broken to form GTP?
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- Succinate Thiokinase cleaves the high energy Thioester bond of succinyl CoA.
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How is GTP converted to ATP? How much energy is lost in this process?
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GTP and ATP are energetically interconvertible by the nucleoside diphosphate kinase reaction: GTP + ADP<--> GDP + ATP; no energy is lost
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Why is FADH2 formed by Succinate Dehydrogenase instead of NADH?
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Because the reducing power of Succinate is not sufficient to reduce NAD+
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Where are the 3 NADHs formed in the TCA
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1)Alpha KG DH
2)Isocitrate DH 3) Malate DH |
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19. How much ATP is formed by 1 turn of the TCA (starting with Acetyl CoA)? How much is formed if you include the PDH reaction?
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a. 2 NADH, 1 GTP and 1 FADH2 total of 9 ATP
b. With the PDH reaction you would include one more NADH2 making a total of 12 ATP |
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20. Elevated levels of ADP affect TCA by increased production of ATP (therefore increasing the TCA). How do decreased levels of ADP affect the TCA?
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The formation of ATP by oxidative Phosphorylation is decreased because of lack of phosphate acceptor
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What is respiratory control of energy production?
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The rate of oxidative Phosphorylation is proportional to [ADP][Pi] / [ATP] : this is known as respiratory control
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