Figure 2

The relationship of the biomass production and electron transfer rates. The reducing equivalent supplying rates in the (A) DET, (B) MET and (C) Mixed modes, and the NADH consumption rate for cellular use in the (B) MET and (C) Mixed modes, as functions of biomass yield. The line represents the maximal electron transfer rates and biomass production rate, while any point within the pink area represents all allowable electron transfer rates and biomass production rates. The blue area represents the total NADH-consuming flux for normal cellular function. The distance between the two lines across the pink and blue areas represents the total available NADH flux in the cell at a metabolic state related to a specific biomass production rate; inset, enlargement of boxed area. The reducing equivalent represents NADH in the MET mode, whereas it denotes an assumed product of the reaction catalysed by cytochrome c reductase for the DET mode.