Figure 1. Experimental Design for Precision Measurements of O₂ Uptake and CO₂ Production in Time.

(A) A conceptual schematic of the method used for precision measurements of O₂ and CO₂ fluxes in low–density yeast cultures; C_in are the concentrations of gases in the air entering the reactor at rate J_in, and the C_out are the concentrations of gases existing the reactor at rate J_out.

(B) The respiratory quotient (RQ) estimated from O₂ and CO₂ concentrations measured in a low–density yeast culture growing on ethanol as a sole source of carbon and energy equals the RQ estimate from mass-conservation (2/3); the culture was inoculated at a density of 1000 cells/ml and measurements began 70 hours after inoculation, when the cultured had reached a density of about 10⁵ cells/ml. Error bars denote standard deviations. See Figure S1 and the Supplemental Information for more control experiments and details.

See also Figure S1.