Figure 2: Sample traces of exocytosis in eggs for different external calcium concentrations. For each series, the number of newly emerged exocytosis disks in each image frame was counted. This number plus the numbers from all previous frames gave the cumulative number for this time point. Each line correspond to different values of external calcium: 0.4, 2 and 10mM for blue, orange and green points respectively. For fitting we use β = 1x10-6 s-1, ω = 223:6 s-1 in equation (2). Other parameters appear in the box inside the text.