Citric Acid cycle S1M3

  1. What are the alternate names for the citric acid cycle
    • Tricarboxilic acid cycle (TCA)
    • KREBS cycle
  2. The TCA cycle is the gateway to aerobic metabolism for any molecule that can be transformed into what molecules
    • Acetyl group
    • Dicarboxylic acid
  3. Most of the fuel molecules enter the citric acid cycle as
    Acetyl coenzyme A
  4. The products of the citric acid cycle an important precursur for
    Oxidative phosphorylation
  5. What are the main products of the citric acid cycle
    • 3 NADH (high energy electron carrier)
    • FADH2 (high energy electron carrier)
    • 2 CO2
  6. What two mechanisms together provide 95% of the energy used in the human body
    • Citric acid cycle
    • Oxidative phosphorylation
  7. Where is the PDH complex
    In the matrix of the mitochondria
  8. What transports pyruvate into the mitochondria
    Pryuvate translocase with a H+ symport
  9. The PDH complex contains what Enzymes
    • E1
    • E2
    • E3
    • PDH kinase
    • PDH phosphatase
  10. What is the function of E1
    Lose CO2
  11. What is the function of E2
    Makes Acetyl CoA
  12. What is the function of E3
    Produces NADH from NAD+
  13. What is the function of PDH kinase and PDH phosphatase
    Phosphorylation (inactivation) and dephosphorylation (activation) of PDH respectively
  14. Pyruvate Dehydrogenation Deficiency
    • Congenital lactic acidosis
    • Inability to convert pyruvate to acetyl CoA, and therefore is shunted to lactic acid
    • Messes with the brain and muscle due to elevated lactic acid
  15. How can one be treated with PDH deficiency
    • High fat low carb diet (Ketogenic)
    • Dichloroacetate (DCA) blocks PDH Kinase from inactivating PDH
  16. Thiamine deficiency can lead to
    Beriberi disease and Wernicke-Korsakoff Syndrome (common in alcoholics)
  17. What would you see in elevations in a thiamine deficient patient
    • Pyruvate
    • Alanine
    • Lactate
  18. Wernickes encephalopathy
    • Caused by Thiamine deficiency
    • Weakness in eye movements or rapid eye movements
    • Unsteady gate
    • Sudden onset of confusion
  19. Korsakoff Pyschosis
    • Caused by Thiamine deficiency
    • Persistant deficits in learning and memory
  20. What is a classic finding in a deceased Wernicke - Korsakoff patient
    Hemorrhages in mammillary bodies of the brain
  21. What must be the administration sequence in a patient with Wernicke-Korsakoff syndrome
    IV with thiamine must be given before IV of glucose
  22. What inhibits the PDH complex
    • ATP
    • NADH
    • Acetyl CoA
    • PDH kinase
    • High energy charge
  23. PDH phophatase is dependent on
    Mg2+ and Ca+
  24. PDH Kinase is dependent on
    • ATP
    • Mg+
  25. What activates the PDH complex
    • AMP
    • CoA
    • NAD+
    • Ca+
    • PDH phophatase
  26. NADH specifically turns off what portion of the PDH
  27. Acetyl CoA turns off what portion of the PDH
  28. Calcium triggers what complex in the PDH
    PDH phosphatase removing a phosphate from PDH therefore activating it
  29. None of the intermediates in the citric acid cycle are
  30. What reaction in the citric acid cycle is affected by low iron
    • Aconitase is inhibited
    • (conversion of Citrate to isocitrate)
  31. What converts Acetyl CoA and oxalacetate to Citrate
    Citrate synthase (releases a large amount of energy)
  32. Citrate is an allosteric inhibitor of
    Phosphofructose kinase in glycolysis
  33. What converts citrate to isocitrate
  34. Flourocitrate inhibits
  35. What is similar in PDH and alpha-ketoglutarate dehydrogenase complex's
    • They both use E1, 2, and 3
    • Both sensitive to thiamine deficiency
  36. What is the first step to make CO2 and NADH
    Isocitrate dehydrogenase
  37. What is the second step in TCA that makes CO2 and NADH
    Alpha ketoglutarate dehydrogenase complex
  38. What is the only conenzyme between the PDH and KDH that has the same function
  39. Where is the only example of substrate level phosphorylation in the citric acid cycle
    Succinyl CoA creating GTP from GDP and Pi
  40. What step makes FADH2
    Succinate dehydrogenase
  41. When is the third NADH made
    Conversion of Malate to Oxalacetate
  42. When is the only FADH made in the citric acid cycle
    Succinate to Fumarate
  43. Ca+ activates muscle contraction and therefore the demand of ATP activates what in the citric acid cycle
    • Isocitrate Dehydrogenase
    • Ketoglutarate Dehydrogenase
    • PDH complex
  44. Anaplerotic reactions
    Enzyme catalyzed reaction that can replenish the supply of intermediates in the TCA cycle
  45. Alhpa ketogluterate is produced from
    Glutamic acid when proteins are degraded
  46. Citrate is used in the body for what beyond TCA
    Fatty acid synthesis
  47. Succinyl CoA is used in the body beyond the TCA cycle for
    Heme synthesis
  48. Malate is used in the body for what beyond the TCA cycle
  49. Oxalacetate is used in the body beyond the TCA cycle for
    Amino acid synthesis
  50. Alpha ketoglutarate is use in the body for what beyond TCA
    Amino acid synthesis and neurotransmitter synthesis
  51. Pyruvate carboxylase
    • Anaplerotic reaction
    • Replenishes oxaloacetate (requires ATP)
  52. Pyruvate carboxylase is activated by
    Acetyl CoA
  53. Biotin (inhibited by egg whites) is important to what reaction
    Pyruvate carboxylase
  54. What are the cofactors to the PDH complex
    • FAD
    • NAD+
    • Lipoic acid
    • Thiamine pyrophosphate
    • CoA-SH
  55. What is the function of Vit B12 in respect to the TCA cycle
    A coenzyme in the synthesis of Succinyl CoA
Card Set
Citric Acid cycle S1M3