Figure 9.

The irrRAFs schema of the two examples presented in the text. Yellow and green circles are the substances that can pass through the membrane (the concentrations of the yellow ones being keep fixed during the simulations), whereas diamonds and white circles represent, respectively, the reaction and the reaction products. Reactions indeed occur on both sides of the membrane, but because the different size of protocell and environment their effects are significant only on the interior of the protocell, while on the other side they are quickly (in our model, instantaneously) diluted—see Section 6 for a discussion