Amino acids are necessary to mammalian cell cultures both for protein synthesis and as an energy source. In this study, we present an unstructured mathematical model describing (i) cell growth and death kinetics and (ii) metabolism of glucose and 19 amino acids for HEK-293 and CHO IFN-gamma cell cultures. The proposed mathematical framework is in good agreement with experimental data for both cell lines. It accommodates the inclusion of expressions for other cellular activities, such as the production of recombinant viral vectors or proteins, and can be used as the basis for the development of a model library for mammalian cell cultures.