Cell model for simulation, molecular diffusion rates, and receptor movement. (A) The cell model used for simulation. See text for details. (B) Distribution of diffusion rates (υ). For details, see text. (C,D) Movement of R was plotted for 1 × 104 steps at intervals of 10 steps. The diffusion rates of R used were υ(C) and 0.1υ(D). The numbers of subspaces were 600 × 600 × 1 (C) and 300 × 300 × 1 (D).