Question

Net gain of ATP molecules per hexose during aerobic respiration is

• A. 12
• B. 18
• C. 36
• D. 30

Answer 1

Answer: (C)

36

Answer 2

Net gain of ATP during aerobic respiration.
(i) Glycolysis provides 2 ATP molecules and $2 NADH +H^{+}$
(ii) Pyruvate oxidation yields $2 NADH +2 H^{+}$
(iii) Krebs cycle produces 2 GTP molecules, $6 NADH +H^{+}$ and $2 F A D H_{2}$ molecules.
(iv) Electron transport system one NADH $+H^{+}$ produce 3ATP and $F A D H_{2}$ produce 2 ATP molecules in ETS.
Hence, ETS alone produces 32 or 34 ATP. 2 ATP from glycolysis + 2 GTP from TCA cycle and $32 / 34$ ATP from ETS/ETC $=38 / 36$ ATP molecule.