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Citric Acid Cycle Practice 1 definitions

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  • Pyruvate Dehydrogenase Complex
    Located in the mitochondrial matrix, this multi-enzyme system uses TPP, lipoate, and FAD as cofactors to convert pyruvate to acetyl CoA.
  • TPP
    A cofactor essential for decarboxylation reactions in the mitochondrial matrix, particularly in the conversion of pyruvate to acetyl CoA.
  • Lipoate
    A cofactor involved in acyl group transfer during the conversion of pyruvate to acetyl CoA within mitochondria.
  • FAD
    A cofactor participating in redox reactions, notably in the pyruvate dehydrogenase complex and succinate dehydrogenase.
  • NAD
    A molecule that accepts electrons during metabolic reactions, forming NADH in the pyruvate dehydrogenase complex.
  • Acetyl CoA
    A two-carbon molecule entering the citric acid cycle, formed from pyruvate but not considered a cycle intermediate.
  • Citrate
    A six-carbon compound formed by the condensation of acetyl CoA and oxaloacetate at the start of the citric acid cycle.
  • Isocitrate
    A citric acid cycle intermediate formed from citrate, involved in subsequent decarboxylation steps.
  • Oxaloacetate
    A four-carbon molecule that combines with acetyl CoA to initiate the citric acid cycle and can be labeled for isotope tracing.
  • Succinate
    A citric acid cycle intermediate whose concentration increases when succinate dehydrogenase is inhibited.
  • Fumarate
    A citric acid cycle intermediate whose concentration decreases when succinate dehydrogenase is competitively inhibited.
  • Malonate
    A competitive inhibitor of succinate dehydrogenase, causing changes in succinate and fumarate levels.
  • Decarboxylation
    A process in the citric acid cycle where carbon atoms are lost as CO2, affecting isotope labeling outcomes.
  • Mitochondrial Matrix
    The compartment within mitochondria where the pyruvate dehydrogenase complex and citric acid cycle reactions occur.
  • Isotope Tracing
    A technique using labeled molecules, such as carbon-14, to track metabolic flux and carbon loss in biochemical cycles.