Which of the following processes produces the most ATP in cellular respiration?

• A. Electron Transport Chain
• B. Krebs Cycle
• C. Fermentation
• D. Glycolysis

Answer: (A)

Verified step by step guidance

1. Begin by understanding the overall process of cellular respiration, which includes Glycolysis, the Krebs Cycle, and the Electron Transport Chain. Each of these stages contributes to ATP production.
2. Glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate, producing a small amount of ATP. Specifically, it generates 2 ATP molecules per glucose molecule.
3. The Krebs Cycle, also known as the Citric Acid Cycle, takes place in the mitochondria. It processes pyruvate to produce electron carriers (NADH and FADH2) and a small amount of ATP, typically 2 ATP molecules per glucose molecule.
4. Fermentation is an anaerobic process that occurs when oxygen is not present. It allows glycolysis to continue by regenerating NAD+, but it does not produce additional ATP beyond what glycolysis generates.
5. The Electron Transport Chain is the final stage of cellular respiration, located in the inner mitochondrial membrane. It uses electrons from NADH and FADH2 to create a proton gradient that drives ATP synthesis through oxidative phosphorylation, producing the most ATP, approximately 34 ATP molecules per glucose molecule.