Question

Give a detailed accounting of how many ATP are generated through oxidative metabolism (AEROBIC GLYCOLSIS) of one molecule of glucose during exercise. Your answer should include a detailed accounting of exactly where the ATP were generated and should add up to your correct total # of ATP. Please highlight or bold your ATP counts.

Answer 1

The aerobic catabolism of one glucose molecule generates a theoretical maximum of 38 ATP, with 4 ATP from substrate-level phosphorylation and 34 from oxidative phosphorylation. However, the actual yield can be lower.

Step-by-step explanation:

Aerobic metabolism of one molecule of glucose through glycolysis, pyruvate oxidation, and the citric acid cycle generates a significant amount of ATP.

Detailed accounting:

• Glycolysis:
  
  - Gross production: 4 ATP
  
  - Net production (accounting for the 2 ATP used to start glycolysis): 2 ATP
• Transition Reaction (pyruvate to acetyl-CoA):
  
  - Per glucose molecule, 2 NADH are produced, each resulting in the generation of 3 ATP (Total: 6 ATP) through the electron transport chain.
• Citric Acid Cycle (per two turns, since each glucose results in two acetyl-CoA):
  
  - ATP production by substrate-level phosphorylation: 2 ATP
  
  - NADH production (3 NADH per cycle x 2 cycles): 6 NADH → 18 ATP
  
  - FADH₂ production (1 FADH₂ per cycle x 2 cycles): 2 FADH₂ → 4 ATP
• Oxidative Phosphorylation:
  
  - From NADH and FADH₂ produced in previous steps: 10 NADH → 30 ATP and 2 FADH₂ → 4 ATP (via the electron transport chain)

This brings the theoretical total amount of ATP produced from one glucose molecule to 4 ATP (substrate-level phosphorylation) and 34 ATP (oxidative phosphorylation), yielding a maximum of 38 ATP. However, the actual yield is often lower due to various factors.