Fig. 1.

Cell sizes (areas, a) as functions of time (t). (A) Six phase-contrast images of a cell, all taken from a single generation at 15-min intervals, starting from 10 min after the previous division, are shown (respectively labeled I–VI). From such images, the area of each cell as a function of time is inferred from the outlines indicated. (B) The area is plotted as a function of time for many generations of a single cell. The generation indicated in teal and by an arrow indicates time period from which images in A are taken. (C) We plot measured areas on a semilogarithmic scale to make the growth law evident. The data shown are from 5 cells over the course of ∼300 generations each in an experiment conducted at 24 °C in complex medium. More than 4,000 growth curves were obtained from ∼100 cells in this experiment; only a small subset is shown here for clarity. The image acquisition rate was 1 frame per minute.