Narrative: Mammalian cell-culture products have led the way to new approaches in medical therapeutics and diagnostics. The major stumbling block to the wide-scale use of this methodology is the cost of producing the products. This proposal intends to attack the economic problems in this infant field, via applied mathematics. Phase I of this project initiated efforts toward developing a quantitative model of mammalian cell that hopefully will provide a rational and cost-effective basis for reactor design, operation, control and scale-up for mammalian cell-culture processes. The proposed work intends to further develop the present model and experimentally validate it to enhance the capability for prediction of performance of novel bioreactor design and operation strategies.