1. A method of optimizing one or more biological activities in cells in a cell culture, comprising: a. calculating one or more optimal cell culture parameters for one or more biological activities in a cell in a cell culture by applying an optimization method to a list of one or more reactions representing or affecting the one or more biological activities, wherein the optimization method uses an intracellular molecular crowding parameter for one or more elements of the one or more reactions to calculate a cell culture parameter for the one or more biological activities in the cells; and b. initiating and/or maintaining the one or more optimal cell culture parameter in a culture of the cells.