The process in which acetyl CoA reacts with oxaloacetic acid to produce citric acid and finally oxaloacetic acid is called the Krebs cycle. In 1937, the British biochemist Sir Hans Krebs first observed these reactions in the breast meat of pigeons, so it is called the Krebs cycle. Oxaloacetic acid is a stable compound called a resident molecule. Acetyl CoA is the chemical link between glycolysis and the Krebs cycle.
The first compound produced in this cycle is citric acid, also known as the citric acid cycle. Again, some compounds produced in this cycle have three carboxylic (-COOH) groups, so it is called Tricarboxylic Acid cycle. It is also called amphibolic pathway.