  We investigate the properties of large random conservative chemical reaction
networks composed of elementary reactions endowed with either mass-action or
saturating kinetics, assigning kinetic parameters in a
thermodynamically-consistent manner. We find that such complex networks exhibit
qualitatively similar behavior when fed with external nutrient flux. The
nutrient is preferentially transformed into one specific chemical that is an
intrinsic property of the network. We propose a self-consistent proto-cell toy
model in which the preferentially synthesized chemical is a precursor for the
cell membrane, and show that such proto-cells can exhibit sustainable
homeostatic growth when fed with any nutrient diffusing through the membrane,
provided that nutrient is metabolized at a sufficient rate.
