What is the function of the Krebs cycle?

The Krebs cycle, also known as the citric acid cycle or the tricarboxylic acid (TCA) cycle, primarily functions to break down acetyl CoA. This molecule is derived from the breakdown of carbohydrates, fats, and proteins, providing a crucial entry point into the cycle. Within the cycle, acetyl CoA combines with oxaloacetate to form citrate, and through a series of enzymatic reactions, it is oxidized and decarboxylated, ultimately regenerating oxaloacetate. This process releases energy stored in the form of ATP, and also produces key electron carriers like NADH and FADH2, which are essential for the electron transport chain where further ATP production occurs.

While other processes such as glycolysis break down glucose and fatty acids may enter the Krebs cycle as acetyl CoA, the cycle itself specifically focuses on the metabolism of this molecule. Therefore, the identification of the Krebs cycle's function as the breakdown of acetyl CoA is integral to understanding how energy is harvested from nutrients in cellular respiration.