Fig. 4. Simulated profiles of the concentrations of intraflagellar materials (solid lines) and dynein ATPase activity (broken lines; relative values) along flagella. The simulation was executed based on the model by Tombes et al. (Tombes et al., 1987). The lengths of flagella were set to 40 µm (A,C) and 100 µm (B,D). The ATP diffusion coefficients of 150 (A,B) and 60 µm² s^–1 (C,D) were used. The diffusion coefficients of other molecules are shown in Table 2. In A and B, where we used D=150 µm² s^–1, we obtained almost the same results as those previously reported by Tombes et al. (Tombes et al., 1987).