Fig. 3. pH_i during the cell cycle. Phluorin-expressing wild-type or cdc2-1w cells were grown to early logarithmic phase in EMM pH 5.5 and the pH_i and cell length measured for each individual cell. Top: scatter plots of internal pH as a function of cell length. Open diamonds indicate binucleate cells, whereas closed diamonds indicate uni-nucleates. The linear line of best fit is shown in red. Approximate cell-cycle phases are indicated. Bottom: cells were classified into arbitrary 1 µm size classes and the mean internal pH of the created classes calculated. Error bars indicate s.d.