Cell Polarity — Wave-Pinning Model

Cell polarity arises from a reaction-diffusion system where an active membrane-bound form (u, blue) converts slowly diffusing cytoplasmic form (v, red) via autocatalytic feedback f(u) = (a + u²)/(1 + u²). Mass is conserved: ∫(u+v)dx = const. Wave-pinning: a traveling wave self-traps when cytoplasmic protein is depleted. Click canvas to apply local stimulus. High Du/Dv ratio prevents polarization.