Cellular Respiration: Aerobic Respiration Krebs Cycle Electron Transport Chain and ATP Synthase

The Krebs Cycle Occurs in the mitochondria. Produces high- energy molecules (NADH and FADH2), CO2 and 1 ATP Also called the citric acid cycle

Step 1 Pyruvic acid loses one carbon and two oxygen to form CO2 and Acetyl-CoA During this step high energy molecule of NADH is formed

Step 2 Part of Acetyl-CoA combines with a 4-carbon compound to form citric acid During this step two high energy molecules are formed: one FADH2 and one NADH

Step 3 Citric Acid loses one carbon and two oxygen to form CO2 and a 5- carbon compound During this step a high energy molecule of NADH is formed

Step 4 The 5 carbon compound loses one carbon and two oxygen to form CO2 and a 4-carbon compound During this step one high energy molecule of NADH is formed and one ATP is formed

Overall Products of the Krebs Cycle How many CO2 are formed? How many NADH are formed? How many FADH2 are formed? How many ATP are formed?

Electron Transport Chain High energy electrons in NADH and FADH2 created during glycolysis and the Krebs cycle are used to pump H+ ions across the inner membrane of mitochondria to create a concentration gradient. Oxygen acts as a final electron acceptor combining with low energy electrons and H+ ions to form H2O

ATP Synthase The push of H+ ions flowing down their concentration gradient through an enzyme called ATP Synthase converts ADP into ATP ADP ATP

Total ATP formed from aerobic respiration from one molecule of glucose 2 ATP from glycolysis 4 ATP from the 2 NADH formed in glycolysis 2 ATP from the Krebs cycle 24 ATP from the 8 NADH formed from the Krebs cycle 2 ATP from the 2 FADH2 formed from Krebs cycle