series of degrading reactions catabolism in the aerobic cell there are two routes for atp synthesis 1 substrate level phosphorylation where an energy rich phosphoryl group is transferred directly from a high energy intermediate metabolite to adp and 2 oxidative phosphorylation where the free energy is first transformed into redox free energy by oxidizing the energy source then into a proton gradient by respiration and finally the proton gradient is used by the h atpase to drive atp synthesis from adp and inorganic phosphate in other cases e g anaerobic growth there is only the first route substrate level phosphorylation that can be used for atp synthesis an example hereof is the homolactic lab where lactose is converted through the glycolytic pathway to lactic acid which is excreted from the cells and thereby lowers the ph of the growth medium usually milk products with respect to atp generation homolactic fermentation is a very inefficient process and only four moles of atp are produced from 1 mole of lactose through substrate level phosphorylation the anabolic atp consuming and catabolic atp producing fluxes are normally well balanced in the living cell and therefore in the wild type cell under normal growth conditions the catabolic fluxes will be proportional to the anabolic fluxes if a reaction is introduced that for instance hydrolyzes atp in the cell and thereby lowers the cellular energy state i e the atp adp ratio then either catabolism should increase or anabolism growth should decrease in order to make the consumption rate equal the production rate again which of these two scenarios will take place depends on whether.