L31: Gluconeogenesis and PPP

• What are the components used to regenerate ATP?

  ADP and inorganic phosphate (P<i>)
• Why is NAD⁺ needed in cellular processes?

  NAD⁺ is needed for the oxidation of G-3-P.
• What happens to pyruvate under aerobic conditions?

  Pyruvate is oxidized in the citric acid cycle.
• How does the electron transport chain (ETC) function in relation to NADH?

  NADH transfers electrons to O₂, forming H₂O and regenerating NAD⁺.
• What are the fermentation products in animal muscle and some microorganisms?

  Lactate in animal muscle and ethanol in plants and yeast.
• What role does glycolysis play in modern organisms?

  Glycolysis is central to carbohydrate breakdown.
• What is the overall reaction for the oxidation of glucose?

  Glucose + 6O₂ → 6CO₂ + 6H₂O.
• What does a negative ΔG indicate about a reaction?

  A negative ΔG indicates that the reaction is energetically favorable and can proceed spontaneously.
• Where does the citric acid cycle take place?

  The citric acid cycle takes place in the matrix of mitochondria.
• What is the role of Coenzyme A in metabolism?

  Coenzyme A serves as a carrier of activated acyl groups linked via a thioester bond.
• What is the result of the conversion of pyruvate to acetyl CoA?

  The conversion produces acetyl CoA, CO₂, and NADH.
• What type of reaction is the conversion of pyruvate to acetyl CoA?

  It is an irreversible reaction catalyzed by the pyruvate dehydrogenase multienzyme complex.
• What are the advantages of multienzyme complexes in metabolic pathways?

  They minimize side reactions and coordinate regulation of sequential reactions.
• How is the pyruvate dehydrogenase complex controlled?

  It is controlled by phosphorylation and dephosphorylation based on energy status.
• What is a symptom of pyruvate dehydrogenase deficiency?

  Energy production is compromised.
• What does the sparker effect demonstrate in metabolic reactions?

  The sparker effect shows that organic acids can catalytically enhance the oxidation of pyruvate.
• What are the alternative names for the citric acid cycle?

  The citric acid cycle is also known as the Krebs cycle and the tricarboxylic acid (TCA) cycle.
• What are the products of the citric acid cycle?

  The products include 2 CO₂, 3 NADH, FADH₂, and GTP.
• What regulates the citric acid cycle?

  ATP and NADH are the principal negative regulators of the citric acid cycle.
• What are anaplerotic reactions and why are they important?

  Anaplerotic reactions replenish citric acid cycle intermediates to prevent depletion.
• What is the main source of pyruvate for the citric acid cycle?

  The main source of pyruvate is glycolysis.