The Electron Transport Chain in Metabolism: Anaerobic Respiration

• NADH and FADH₂ carry electrons from glycolysis/Krebs cycle to the ETC
• NADH electrons generate ~ 2 ATP per NADH - less ATP than aerobic respiration because less energy is released when N, S, Fe or CO2 accept the electrons
• FADH₂ generates ~ 1 ATP because its electrons enter the ETC at a lower point
• The final electron acceptor is
  • Nitrate or nitrite (Enterobacteria, Clostridium)
  • Sulfate, sulfite, or sulfur (Desulfovibrio, Desulfuromonas)
  • Iron (+3) (Geobacter)
  • CO₂ (Methanococcus)
• Waste products generated from anaerobic respiration are
  • Nitrite, nitrogen gas, or ammonium
  • Sulfite, sulfur, or hydrogen sulfide
  • Iron (+2)
  • Methane
• Anaerobic respiration uses reductases