Question

How does electronegativity of an oxygen atom compare to the electronegativity of other molecules in the electron transport chain?

Answer 1

The electron transport chain (ETC) is the last part of aerobic respiration and is the only component of aerobic respiration that employs atmospheric oxygen. The ETC is a series of proteins that transfer electrons from donor molecules to acceptor molecules via redox reactions. ETC reduces molecular oxygen (atmospheric oxygen, O₂) to water (H₂O) while other molecules like NADH and FADH₂ are oxidized to the corresponding oxidized species. Infact, ETC oxidized protons (H⁺) to water.

The electronegativity of atomic oxygen is key to the redox processes taking place in ETC. It is known that oxygen is the second most electronegative element in the periodic table (fluorine is the most electronegative element) and as such, has a strong tendency to attract electrons from other molecules toward itself. This attraction for electrons is the reason that NADH is oxidized to NAD⁺ or FADH₂ is oxidized to FAD while oxygen is reduced.