Cellular respiration is a catabolic process that occurs in the mitochondria of plants and animals. It uses oxygen to break down glucose and other food molecules to extract energy in the form of ATP. The process involves four main stages: glycolysis, the Krebs cycle, and the electron transport chain and oxidative phosphorylation. This releases energy to produce up to 38 ATP per glucose molecule.

1. Cellular Respiration copyright cmassengale

24. 3. Krebs Cycle (Citric Acid Cycle) copyright cmassengale Krebs Cycle 1 Acetyl CoA (2C) 3 NAD + 3 NADH FAD FADH 2 ATP ADP + P (one turn) OAA (4C) Citrate (6C) 2 CO 2

25. 3. Krebs Cycle (Citric Acid Cycle) copyright cmassengale Krebs Cycle 2 Acetyl CoA (2C) 6 NAD + 6 NADH 2 FAD 2 FADH 2 2 ATP 2 ADP + P (two turns) OAA (4C) Citrate (6C) 4 CO 2

29. 4. Electron Transport Chain (ETC) and Oxidative Phosphorylation ( Chemiosmosis ) copyright cmassengale Inner membrane Outer membrane Inner membrane space Matrix Cristae

30. 4. ETC and Oxidative Phosphorylation ( Chemiosmosis for NADH ) copyright cmassengale NADH + H + ATP Synthase 1H + 2H + 3H + higher H + concentration H + ADP + ATP lower H + concentration H + (Proton Pumping) P E T C NAD+ 2H + + 1/2 O 2 H 2 O Intermembrane Space Matrix Inner Mitochondrial Membrane

31. 4. ETC and Oxidative Phosphorylation (Chemiosmosis for FADH 2 ) copyright cmassengale FADH 2 + H + ATP Synthase 1H + 2H + higher H + concentration H + ADP + ATP lower H + concentration H + (Proton Pumping) P E T C FAD+ 2H + + 1/2 O 2 H 2 O Intermembrane Space Matrix Inner Mitochondrial Membrane

34. Maximum ATP Yield for Cellular Respiration (Eukaryotes) 36 ATP (maximum per glucose) copyright cmassengale Glucose Glycolysis 2ATP 4ATP 6ATP 18ATP 4ATP 2ATP 2 ATP (substrate-level phosphorylation) 2NADH 2NADH 6NADH Krebs Cycle 2FADH 2 2 ATP (substrate-level phosphorylation) 2 Pyruvate 2 Acetyl CoA ETC and Oxidative Phosphorylation Cytosol Mitochondria

38. copyright cmassengale