During the Krebs cycle, how many carrier molecules are produced?

The Krebs cycle, also known as the citric acid cycle, is a crucial metabolic pathway that occurs in the mitochondria and plays a vital role in cellular respiration. During each turn of the Krebs cycle, various carrier molecules are generated that facilitate the transfer of electrons to the electron transport chain, ultimately aiding in ATP production.

In this cycle, for each acetyl-CoA molecule that enters the cycle, three NADH molecules and one FADH2 molecule are produced, along with one ATP (or GTP, depending on the cell type). Since one molecule of glucose is converted into two acetyl-CoA molecules during glycolysis, the Krebs cycle runs twice for every single glucose molecule.

Thus, per glucose molecule, the total yield from the Krebs cycle is:

• 6 NADH (3 per acetyl-CoA x 2)

• 2 FADH2 (1 per acetyl-CoA x 2)

• 2 ATP (or GTP, 1 per acetyl-CoA x 2)

This aligns with the selected answer of 6 NADH and 2 FADH2, which accurately reflects the total number of these electron carriers that are produced during the Krebs cycle per molecule of glucose metabolized.