Question

NADH and FADH are electron carrier molecules with different energy. Being at different energy, how different these molecules donate their electron at the electron transport system (ETC).

Culd someone help to explain to me the process and how it relates to the Complexes used and why NADH produced 3 ATPs and FADH only 2 ATPs? This is for Biochemistry subject.

Answer 1

NADH supplies electrons from complex 1 (electron carrier) to oxygen ( final electron acceptor). Hence NADH contributes to movement of more protons from mitochondria matrix to intermembrane space subsequently produces more number of ATP ( each ATP production requires 3 proton movement from intermembrane space to mitochondria matrix)

FADH supplies electrons from complex II to oxygen. Hence, it causes less to the movement of less protons from mitochondria matrix to intermembrane space, subsequently less number of ATP.