Oxidative Phosphorylation

• What are the four stages of aerobic respiration?

  1. Glycolysis
  2. Link Reaction
  3. Krebs Cycle
  4. Oxidative Phosphorylation
• What happens during glycolysis?


  The 6-carbon glucose is split into two 3-carbon pyruvate molecules
• What is produced during the Link Reaction?


  Two 3-carbon pyruvate molecules are converted into a 2-carbon molecule called acetylcoenzyme A
• What occurs in the Krebs Cycle?


  Acetylcoenzyme A enters a cycle producing ATP and large amounts of reduced NAD and FAD
• What is the main function of oxidative phosphorylation?


  To synthesize ATP using electrons from reduced NAD and FAD, producing water as a by-product
• What is the overall equation for aerobic respiration?


  Glucose + Oxygen → Carbon dioxide + Water + Energy (ATP)
• Where does oxidative phosphorylation take place?


  In the cristae of mitochondria
• What role do reduced NAD and FAD play in oxidative phosphorylation?


  They donate electrons to the first molecule in the electron transport chain
• What happens to electrons as they pass along the electron transport chain?


  They release energy that causes the active transport of protons across the inner mitochondrial membrane
• What is the result of protons accumulating in the intermembranal space?


  They diffuse back into the mitochondrial matrix through ATP synthase channels
• What is the final acceptor of electrons in the electron transport chain?


  Oxygen
• How does oxygen contribute to the electron transport chain?


  It prevents the backup of hydrogen ions and electrons, maintaining the proton gradient
• What is the process of ATP synthesis during oxidative phosphorylation?


  • Electrons from reduced NAD and FAD enter the electron transport chain
  • Energy from electrons causes proton transport across the membrane
  • Protons flow back through ATP synthase
  • ATP is synthesized from ADP and inorganic phosphate
• What similarities exist between oxidative phosphorylation and photophosphorylation in photosynthesis?

  • Both involve electron transport chains
  • Both utilize proton gradients to synthesize ATP
  • Both processes involve chemiosmosis