The Living State
All the living organisms contain tens and thousands of chemical compounds. They are called as metabolites or biomolecules. These are present at concentrations characteristic of each of them.
For example, the blood concentration of glucose in a normal healthy individual is 4.5-5.0 mM (mmol/L, i.e., millimoles/litre), while that of hormones would be nanograms / mL (millilitre).
All living organisms exist in a steady-state characterised by concentrations of each of these biomolecules. These biomolecules are in a metabolic flux. Any physical or chemical process moves spontaneously to equilibrium. The steady state is a non-equilibrium state. As living organisms work continuously, they cannot afford to reach equilibrium. Hence the living state is a non-equilibrium steady-state to be able to perform work. All living process has a constant effort to prevent falling into equilibrium. This is achieved by energy input. This is because, the energy input is equal to the work done by the organisms. So, metabolism (the chemical processes that change food) provides a mechanism for the production of energy. Hence the living state and metabolism are synonymous. Without metabolism there cannot be a living state.