Creation and Reproduction of Model Cells with Semipermeable Membrane

A high activity of reactions can be confined in a model cell with a semipermeable membrane in the Schl\"ogl model. It is interpreted as a model of primitive metabolism in a cell. We study two generalized models to understand the creation of primitive cell systems conceptually from the view point of the nonlinear-nonequilibrium physics. In the first model, a single-cell system with a highly active state confined by a semipermeable membrane is spontaneously created from an inactive homogeneous state by a stochastic jump process. In the second model, many cell structures are reproduced from a single cell, and a multicellular system is created.