Previous calcium simulation results match the qualitative trends in these results. (a) We fitted the trend in peak values with a linear function against the cytoplasm volume; r2 = 0.8776 for the linear fit. We fixed the y intercept at zero. (b) We fitted the decay dynamics of each calcium transient with c · exp(−kt) and report the decay time constant, k. We fitted the trend in decay time constants as a function of cytosolic volume with an exponential a · exp(−bV), where V is the cytosolic volume; r2 = 0.4283 for the fit. (c) We fitted the trend in peak values with a linear function against the volume-to-surface-area ratio; r2 = 0.3492 for the linear fit. (d) We fitted the trend in decay time constants as a function of volume-to-surface-area ratio with an exponential a · exp(−bζ), where ζ is the volume-to-surface-area ratio; r2 = 0.9054 for the fit.
