Figure 1.

Schematic model and an example of the basic properties of cell regulation, which can be simulated using PyEcoLib. (A) The division is modeled as a stochastic process that occurs after completion of the M stages. During division, the cell resets the stages to zero. The transition rate from any stage m to another stage $m+1$ is given by ${k{d}^S}^{\lambda }$, where $k_d$ is a constant, s is the cell size, and $\lambda >0$ defines the strength of division control. Throughout the cell cycle, the cell grows exponentially with an exponential growth rate μ and is halved during division. (B) Cell size dynamics. Top: time series of a cell growing and dividing. one of the two descendant cells (gray) is discarded. Bottom: example of cell size trajectories that can be simulated using PyEcoLib. These trajectories can include different sources of noise, such as initial size noise, growth rate noise, and partition noise. (C) The adder division strategy for simulated trajectories. Following this strategy, the cell size added during each cell cycle does not show a correlation with the cell size at birth.