Question

Why 2.5 ATP for NADH but 1.5 ATP for FADH2?

A) NADH has more energy-rich electrons
B) FADH2 undergoes more oxidation-reduction reactions
C) NADH participates in different stages of cellular respiration
D) FADH2 is more efficient in ATP synthesis

Answer 1

NADH produces 2.5 ATP, while FADH2 produces 1.5 ATP in the electron transport chain. This difference is due to NADH having more energy-rich electrons, participating in different stages of cellular respiration, and FADH2 being less efficient in ATP synthesis.

Step-by-step explanation:

In the electron transport chain (ETC), NADH produces 2.5 ATP, while FADH2 produces 1.5 ATP. This difference in ATP production is due to the following reasons:

1. NADH has more energy-rich electrons: NADH enters the ETC at Complex I and donates its electrons at a higher energy level compared to FADH2, which enters at Complex II. The higher energy electrons from NADH pump more protons across the membrane and generate a larger proton gradient, resulting in the production of more ATP.
2. NADH participates in different stages of cellular respiration: NADH is produced in glycolysis, the pyruvate dehydrogenase complex, and the citric acid cycle, while FADH2 is only produced in the citric acid cycle. NADH's participation in multiple stages leads to the production of more ATP.
3. FADH2 is less efficient in ATP synthesis: FADH2 donates its electrons at a lower energy level, resulting in the pumping of fewer protons and the production of fewer ATP molecules during oxidative phosphorylation.