Tricarboxylic acids (TCA) are organic compounds that contain three carboxyl groups (-COOH) in their molecular structure. They play a crucial role in various biochemical processes, particularly in the Krebs cycle, which is essential for energy production in living organisms. The most well-known tricarboxylic acid is citric acid, commonly found in citrus fruits. These acids are important in metabolism, as they help in the breakdown of carbohydrates, fats, and proteins to produce energy. In addition to citric acid, other examples of tricarboxylic acids include isocitric acid and alpha-ketoglutaric acid, which also participate in metabolic pathways.