Question

Redox: The best initial electron donor for an organism performing fermentation would be ___, while the best final electron acceptor would be ___ .

Use the information from the redox couples below to answer the fill in the blank questions, using the letter after each substance. (i.e. if you believe that the answer is CoQ fill in the appropriate blank with the letter A). Each letter (substance) may be used more than once. Hint: put the redox couples into an accurate electron tower first, based on their redox potentials. Redox Couples (potential in volts) CoQ (A)/CoQH2 (B) +0.10 V; Fe3+ (c)/Fe2 (D)- +0.771 V; SO42(E)/S°(F) -0.20 V NO2 (G)/NH4 (H) +0.44 V; CO2 (1)/glucose(U)--0.43 V; CO2(K)/CH4(L) 0.24 V NAD (M)/NADH(N)--0.32 V; H (O)/H2(P)--0.42V; O2 (Q)/H2O(R)- +0.815 V pyruvate(S)/lactate(T) 0.19 V; S°(U)/H2S(V)--0.27 V; NO3(W)/N2(X) +0.74 V. 4. The best initial electron donor for an organism performing fermentation , while the best final electron acceptor would be would be

Answer 1

Flow of electrons takes place from electron donor to the electron acceptor molecule, In a redox reaction, electron move spontaneously from atoms or molecules having a negative or less positive reduction potentials to atoms or molecules having more positive reduction potentials. In case of fermentation, glucose molecule is catabolized in the absence of the oxygen and it does not use O₂ as the final electron acceptor. In fermentation, NADH passes electrons to the pyruvate and it is oxidized to NAD⁺.

4. The best initial electron donor for an organism performing fermentation would be NADH(N), while the best final electron acceptor would be Pyruvate(S).