(a) (b)Figure 2. Temporal evolution of donor population towards steady state. PrgB is a protein made by the donor cell in response to the signal dispatched by the recipient which facilitates transfer of plasmid. The “on” cells are ready to transfer plasmid while the “off” cells are not. Note the substantial difference in the steady states predicted by the population balance model and the single cell model. (a) Population balance model. (b) Single cell model