Final answer:
The Cori Cycle and cellular respiration involve multiple stages where ATP is produced from glucose. In glycolysis, ATP is used and pyruvate is formed, which then enters the citric acid cycle, yielding ATP, NADH, and FADH2. These electron carriers contribute to oxidative phosphorylation, where the majority of ATP is generated.
Step-by-step explanation:
The student's question pertains to the Cori Cycle and the generation of ATP molecules during cellular respiration, including phases such as glycolysis and the citric acid cycle. During glycolysis, glucose is phosphorylated at the expense of two ATP molecules, with the end result being two molecules of pyruvic acid. Upon entry into the citric acid cycle, each glucose molecule, which has been converted into two pyruvate molecules, will ultimately yield (per cycle) one ATP from substrate-level phosphorylation, one FADH2, and three NADH molecules. Additionally, in the step involving GTP, it can be converted to ATP in eukaryotic cells, whereas some bacteria can produce ATP directly.
For every glucose molecule, two turns of the citric acid cycle are required, doubling the output to two ATPs, two FADH2, and six NADH, which then enter the oxidative phosphorylation system, further contributing to ATP production. It is important to multiply the number of ATP, NADH, and FADH2 by two after glycolysis to reflect the fact that each glucose molecule produces two pyruvate molecules. The difference in the number of ATP molecules formed through cellular respiration can be attributed to the efficiency of the oxidative phosphorylation system and the energy yield from NADH and FADH2.