How many NADH molecules are produced during one turn of the citric acid cycle?

During one turn of the citric acid cycle, also known as the Krebs cycle, a total of three NADH molecules are produced. This cycle is a series of enzymatic reactions that occurs in the mitochondrial matrix and plays a crucial role in cellular respiration by oxidizing acetyl-CoA derived from carbohydrates, fats, and proteins into carbon dioxide and capturing high-energy electrons in the form of NADH and FADH2.

In detail, NADH is generated at three specific steps in the cycle:

1. The conversion of isocitrate to alpha-ketoglutarate involves the oxidation of isocitrate, leading to the reduction of NAD+ to NADH.
2. The transformation of alpha-ketoglutarate to succinyl-CoA also produces another molecule of NADH as it is further oxidized.
3. Finally, the conversion of malate to oxaloacetate results in the formation of a third NADH molecule.

Through these three key steps, the cycle effectively captures energy stored in the form of electrons, which can later be utilized in the electron transport chain to produce ATP. Understanding this process highlights the efficiency of cellular respiration and the importance of NADH in energy production.