We are modifying existing N-response networks to explain the effects of changing NO_3- uptake rate and cellular concentrations (metabolic output) on transcript and metabolite levels. The inputs for this level include kinetic parameters of the N response models of Arabidopsis, specific gene perturbations, and NO_3- concentrations predicted from the molecular level model. The outputs of this level will include semi-quantitative predictions for changes in levels of transcripts, metabolites, and proteins, which will be used as both input for subsequent models and feedback model inputs for the molecular level.