How many nadh molecules are created from the pyruvate molecules that enter the Krebs cycle?

Answer: Three molecules of NADH is produced from every molecule of pyruvate that enters the Krebs cycle.

Explanation: Pyruvate produced from glycolysis is broken down to Acetyl CoA which then enters the Krebs cycle. In Krebs cycle, each molecule of acetyl CoA yields one molecule of GTP (ATP), one molecule of FADH2 and three molecules of NADH. The main purpose of Krebs cycle is to generate NADH needed in the cells. Krebs cycle is a series of eight enzyme catalyzed reactions which oxidizes the Acetyl CoA produced from pyruvate. The NADH molecules are produced by dehydrogenase enzymes:

1). Isocitrate dehydrogenase which converts isocitrate to alpha ketoglutarate.

2). Alpha ketoglutarate dehydrogenase which converts alpha ketoglutarate to succinyl CoA.

3). Malate dehydrogenase which converts malate to oxaloacete.