Q. Why is the Krebs cycle also called the final common pathway of the degradation of organic compounds?
The Krebs cycle is known as the final common pathway of the degradation of organic compounds because it is also possible to generate acetyl CoA from the degradation of lipids and proteins.
Since acetyl CoA is the substrate that triggers the Krebs cycle this process is called the final common pathway for being activated by other organic molecules (proteins and lipids) and not only by glucose.
The organism uses energetic reserves of proteins and fat to cycle the Krebs cycle when undergoing malnutrition or when there is no glucose available for the cells.