Intracellular protein Dietary protein Amino acids NH Carbon skeletons Biosynthesis of amino acids, 4/ nucleotides, and biological amines v Carbamoyl phosphate a-Keto acids Aspartate- arginine- Urea Citric succinate cle acid CO2+H2O shunt of cycle ATE citric acid cle Oxaloacetate U (nitrogen excretion product) Glucose (synthesized in gluconeogenesis)