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22 Cards in this Set

  • Front
  • Back
Main function of TCA
provide
where does TCA occur?
mitochondrial matrix
what enzyme converts pyruvate to acetyl coA
Pyruvate Dehydrogenase Complex
1) pyruvate Dehydrogenase (E1)
2) Dihydrolipoyl transacetylase (E2)
3) Dihydrolypoyl DH (E3)
How many NADH and FADH are produced?
3 NADH
2 FADH2
1 GTP
How many ATP per circle of TCA?
12

NADH = 3 ATP
FADH2 = 2 ATP
What inhibits PDH?
1) Protein Kinase stimulated by ATP, NADH and Acetyl CoA
What is the inactivated form of PDH?
cAMP independent PK is P --> E1 inhibited
Activated form of PDH
Phosphoprotein phosphatase activates and dephos occurs of PDH
What activates the Protein kinase?
- increased ATP
- increased NAD+ and CoA inhibits
How much ATP from 1 pyruvate to 1 acetyl CoA
3 ATP = NADH
effect of citrate on glycolysis
inhibition of PFK1 so inhibition of glycolysis
Regulatory steps of TCA
1) Citrate Synthase
2) Isocitrate DH
3) α KG DH
4) Succinate DH
What would lower NAD+ levels do to Isocitrate DH?
inhibit or slow it down
increased NADH on α KGDH?
inhibit or slow it down
Where are 2 CO2 molecules released in TCA?
Isocitrate DH
α KG DH
What bond is broken to form GTP?
- Succinate Thiokinase cleaves the high energy Thioester bond of succinyl CoA.
How is GTP converted to ATP? How much energy is lost in this process?
GTP and ATP are energetically interconvertible by the nucleoside diphosphate kinase reaction: GTP + ADP<--> GDP + ATP; no energy is lost
Why is FADH2 formed by Succinate Dehydrogenase instead of NADH?
Because the reducing power of Succinate is not sufficient to reduce NAD+
Where are the 3 NADHs formed in the TCA
1)Alpha KG DH
2)Isocitrate DH
3) Malate DH
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?
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
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?
The formation of ATP by oxidative Phosphorylation is decreased because of lack of phosphate acceptor
What is respiratory control of energy production?
The rate of oxidative Phosphorylation is proportional to [ADP][Pi] / [ATP] : this is known as respiratory control