Question

he FoF1 synthesis of ATP depends on delivery of electrons carried by NADH and FADH2 to electron transport systems in the inner mitochondrial membrane in eukaryotic cells . What is the maximum number of ATPs generated for the following?
a. one molecule of FADH2 produced during the citric acid cycle
b. one molecule of NADH produced during the citric acid cycle
c. one molecule of NADH produced by glycolysis in a muscle cell that uses the mitochondrial glycerol phosphate shuttle
d. one molecule of NADH and one molecule of FADH₂ produced in the Krebs Cycle?

Answer 1

The FoF1 synthesis is based upon transfer of electrons from NADH and FADH2 to various complexes used in electron transport chain.

The NADH molecule transfers its electrons to a higher energy complex which is complex 1 and produces 3 molecules of ATP.

Tge FADH2 molecule releases its electrons to a relatively low energy complex, the complex 2 of ETC and gives rise to only two molecules of ATP.

A.) So one molecule of FADH2 obtained from citric acid cycle will produce 2 molecules of ATP.

B.) One molecule of NADH will produce 3 molecules of ATP.

C.) NADH produced by glycolysis will also produce only 3 molecules of ATP. Only the electron is transfered during electron transport chain, irrespective of it origin.

D.) One molecules of NADH will always produce 3 ATP and 1 FADH2 will produce 2 ATP.