Question

How many ATP molecules are synthesized when a NADH is oxidized through complex 1?

a) 1 ATP

b) 2 ATP

c) 3 ATP

d) 4 ATP

Answer 1

Approximately 3 ATP molecules are synthesized when a NADH molecule is oxidized through Complex I of the electron transport chain.

Step-by-step explanation:

When a NADH molecule is oxidized through Complex I of the electron transport chain (ETC) in the mitochondria during cellular respiration, it generates enough proton motive force to synthesize approximately 3 ATP molecules through oxidative phosphorylation.

This is because NADH, entering the ETC at Complex I, provides a high energy yield as it pumps more protons across the mitochondrial membrane compared to FADH2, which enters at Complex II. Accordingly, the correct answer to the student's question is (c) 3 ATP.