Oxidative Phosphorylation and ATP Production

Overview of Cellular Respiration

• Glycolysis and conversion of pyruvate to acetyl CoA
• Krebs (Citric Acid) Cycle
• Direct ATP production and reduction of NAD to NADH
• NADH oxidation releases energy used to create ATP

Key Players in Oxidative Phosphorylation

• NADH: Main molecule oxidized to NAD+
  • Oxidation involves losing electrons, resulting in NAD+, a hydrogen proton, and two electrons
• Oxygen: Final electron acceptor
  • Reduced to form water

Process of Oxidative Phosphorylation

• Involves electron transport chain (ETC)
• Electrons transferred between acceptors (e.g., Co-enzyme Q, Cytochrome C)
• Energy released in steps to pump hydrogen protons across membrane

Mitochondrial Structure

• Outer Membrane
• Inner Membrane
  • Folds called cristae
• Intermembrane Space: Between outer and inner membranes
• Matrix: Inside the inner membrane, location of citric acid cycle

Electron Transport Chain (ETC)

• Series of protein complexes in the inner membrane
• Facilitates electron transfer and proton pumping
• NADH donates electrons and protons, oxidized to NAD+
• Protons pumped from Matrix to Intermembrane Space creating a gradient

ATP Synthesis

• Proton gradient used by ATP Synthase (enzyme complex)
• ATP Synthase: Functions like a rotary engine
  • Protons flow down gradient causing mechanical rotation
  • Rotation drives the formation of ATP from ADP and phosphate

Importance of the Process

• Produces most of the ATP in cellular respiration
• Critical for energy production in living organisms
• Demonstrates cellular processes that power biological functions

Conclusion

• Oxidative phosphorylation is a vital process for ATP production
• Cellular respiration relies heavily on the reduction and oxidation of coenzymes
• Provides a controlled mechanism to harvest energy from nutrients

Understanding this process highlights the intricate biochemical pathways that sustain life.