What substrates are fed into the Citric Acid Cycle?

The substrates that enter the Citric Acid Cycle include acetyl-CoA and oxaloacetate. Acetyl-CoA is derived from the breakdown of carbohydrates, fats, and proteins, and it is the primary fuel that feeds into the cycle, combining with oxaloacetate to form citrate, the first compound in the cycle. Oxaloacetate, which is regenerated at the end of the cycle, is essential in accepting the acetyl group to continue the cycle.

This combination of acetyl-CoA and oxaloacetate is crucial for the cycle to function properly, as it allows the entire process of energy production to proceed, facilitating the conversion of substrates into high-energy electron carriers like NADH and FADH2, which are utilized in the electron transport chain for ATP production. The other options do not accurately represent the substrates that enter the Citric Acid Cycle.