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Citric Acid Cycle Practice 3 quiz

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  • What compounds can citric acid cycle intermediates be used to synthesize?
    Citric acid cycle intermediates can be used to synthesize porphyrins, hemes, amino acids, oxalo acids, and pyrimidines.
  • Which citric acid cycle intermediate is used to make porphyrins and hemes?
    Succinyl CoA is used to make porphyrins and hemes.
  • What is the role of anaplerotic reactions in the citric acid cycle?
    Anaplerotic reactions replenish oxaloacetate to replace intermediates that have been removed from the cycle.
  • Which intermediate is involved in amino acid synthesis?
    Alpha-ketoglutarate is involved in amino acid synthesis.
  • What is oxaloacetate used to produce besides being a cycle intermediate?
    Oxaloacetate is used to produce oxalo acids and pyrimidines.
  • Why are anaplerotic reactions important for the citric acid cycle?
    They are important because they form oxaloacetate to replace intermediates that are diverted for biosynthesis.
  • What happens to CO2 during the isocitrate dehydrogenase reaction?
    CO2 is lost (released) during the isocitrate dehydrogenase reaction.
  • What molecule is reduced during the isocitrate dehydrogenase reaction?
    NAD+ is reduced to NADH during the isocitrate dehydrogenase reaction.
  • How does the isocitrate dehydrogenase reaction differ from the pyruvate dehydrogenase reaction?
    The isocitrate dehydrogenase reaction forms a double bond between oxygen and carbon, which does not occur in the pyruvate dehydrogenase reaction.
  • What is formed from NAD+ in the isocitrate dehydrogenase reaction?
    NADH is formed from NAD+ in the isocitrate dehydrogenase reaction.
  • What is the fate of the carbon atom lost in the isocitrate dehydrogenase reaction?
    The carbon atom is released as CO2.
  • Which citric acid cycle intermediate is a precursor for nucleic acid components?
    Oxaloacetate is a precursor for pyrimidines, which are components of nucleic acids.
  • What is the significance of forming a double bond between oxygen and carbon in the isocitrate dehydrogenase reaction?
    It is a distinguishing feature of this reaction compared to the pyruvate dehydrogenase reaction.
  • What must happen if citric acid cycle intermediates are used for biosynthesis?
    They must be replaced by anaplerotic reactions to maintain the cycle's function.
  • What is the main function of the citric acid cycle besides energy production?
    The citric acid cycle provides intermediates for the synthesis of various important biomolecules.