What are the main components of cell culture media?

Cell culture media contains: carbon source (glucose, glycerol) for energy and biomass, nitrogen source (ammonia, amino acids, yeast extract) for protein synthesis, minerals and trace elements (phosphate, sulfate, iron, zinc) as enzyme cofactors, vitamins (B vitamins, biotin) for coenzyme function, buffers (phosphate, HEPES) for pH stability, and oxygen (for aerobes). Mammalian cell media additionally requires serum or serum replacements, growth factors, and lipids. Media can be defined (chemically characterized) or complex (containing undefined components like yeast extract). Selection depends on organism, product requirements, regulatory considerations, and cost.