AbstractThe kinetics of radioactive SO2uptake byS. cerevisiaevar.ellipsoideus, the effect of temperature on the uptake, the irreversible thermal inactivation of the uptake and the specificity for the molecular form of SO2in the process indicate that mediated transport is operative in this uptake. Both the transport and toxicity of SO2in this yeast are strongly pH‐dependent and the dependence is based on the determining effect pH exerts on the distribution of the forms which SO2assumes in solutio