Question

The synthesis of ATP as a result of the electron transport system is dependent on the delivery of electrons and hydrogen ions by NADH and FADH2 to the inner membrane of the mitochondria in eukaryotic cells or the cell membrane of prokaryotic cells. For each of the situations below, give the maximum number of ATP generated.

a. one molecule of FADH2 produced during the TCA cycle
b. one molecule of NADH produced during the TCA cycle
c. one molecule of NADH produced by glycolysis in a muscle cell that has a very low cytoplasmic level of NADH
d. one molecule of NADH produced by glycolysis in a liver cell using the malate-aspartate shuttle
e. one molecule of FADH2 produced during the TCA cycle in a prokaryotic cell
f. one molecule of NADH produced by glycolysis in a prokaryotic cell

Answer 1

The number of ATP molecules produced varies: FADH2 during the TCA cycle generally yields 2 ATP, while NADH during the TCA cycle yields 3 ATP. Glycolysis-derived NADH provides 2 ATP in muscle cells using shuttle systems, but 3 ATP in liver cells using the malate-aspartate shuttle. Prokaryotic cells yield similar numbers, but without the need for shuttling.

Step-by-step explanation:

ATP Yield from Various Electron Donors

The synthesis of ATP via the electron transport system (ETS) in cellular respiration involves the transfer of electrons from NADH and FADH2 to produce ATP. The amount of ATP produced can vary, especially when considering different cellular conditions, tissues, and organisms.

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These ATP yields are subject to cellular variability and the specific shuttle mechanisms present in different tissues.