Fig. 5.

(A) The equilibrium configuration of the MB is calculated as a function of renormalized tension $\sigma R_0^3/{\kappa }_r$ and renormalized MB length $L/R_0$, in which the volume of the cell is $\frac{4}{3}\pi R_0^3$. The gray dots indicate the simulations performed to calculate the diagram. The configuration of the MB is indicated by colors: white, flat; red, buckled; and pink, bistable (i.e., buckled or flat). The topmost scale indicates the shape parameter of the cell (isotropy $r/R$), at equilibrium in the case where the MB is flat and has a length equal to the cell perimeter. (B) A cut through the phase diagram, for a MB of length $L=7.5R_0$. The degree of coiling (see Methods for definition) is indicated as a function of tension, for a cell that is initially flat (black dots) or buckled (gray dots). In the metastable region, the two trajectories are separated, and the arrows illustrate hysteresis in the system.