Electron Transport Chain and Oxidative Phosphorylation

• What is the name of Complex I in the electron transport chain?

  NADH Dehydrogenase
• What does Complex I accept electrons from?

  NADH
• What is produced when NADH is oxidized in Complex I?

  NAD⁺
• What does Complex I reduce ubiquinone (Q) to?

  Ubiquinol (QH₂)
• What is the role of Complex I in proton pumping?

  Pumps protons from matrix to intermembrane space
• What is the name of Complex II in the electron transport chain?

  Succinate Dehydrogenase
• From where does Complex II receive electrons?

  FADH2
• What process generates FADH2 for Complex II?

  Oxidation of succinate to fumarate
• What does Complex II reduce ubiquinone (Q) to?

  Ubiquinol (QH₂)
• How does Complex II differ from Complex I in terms of proton pumping?

  Complex II does not pump protons
• What is the name of Complex III in the electron transport chain?

  Cytochrome bc₁ Complex
• What does Complex III receive electrons from?

  Ubiquinol (QH₂)
• What does Complex III transfer electrons to?

  Cytochrome c
• What is the role of Complex III in proton pumping?

  Pumps protons from matrix to intermembrane space
• What is the function of cytochrome c?

  Shuttles electrons from Complex III to IV
• What does Complex IV receive electrons from?

  Cytochrome c
• What is the final electron acceptor in the electron transport chain?

  Molecular oxygen (O₂)
• What is produced when molecular oxygen is reduced in Complex IV?

  Water (H₂O)
• What is the role of Complex IV in proton pumping?

  Pumps protons into the intermembrane space
• What is the name of Complex V in the electron transport chain?

  ATP Synthase
• How does ATP synthase generate ATP?

  Utilizes the proton gradient created by the chain
• What do protons do as they flow back into the matrix through ATP synthase?

  Drive the synthesis of ATP
• What is the overall process of oxidative phosphorylation?

  • Electron transport chain creates a proton gradient
  • Protons flow back through ATP synthase
  • ATP is synthesized from ADP and inorganic phosphate (Pi)
• What are the functions and roles of each complex in the electron transport chain?

  • Complex I: Accepts electrons from NADH, pumps protons
  • Complex II: Accepts electrons from FADH2, does not pump protons
  • Complex III: Accepts electrons from ubiquinol, pumps protons
  • Complex IV: Accepts electrons from cytochrome c, pumps protons
  • ATP Synthase: Uses proton gradient to synthesize ATP