How do metabolic pathways keep from reaching equilibrium?

The metabolic chemical reaction is reversible, and they too would attain equilibrium if they take place in a test tube separately. However, if a cell attains metabolic equilibrium it is considered as dead. Thus, a cell in the body is not in equilibrium.  

The spontaneous flow of substances within and outside of the cell prevents the metabolic pathways from attaining an equilibrium, and the cell persists to perform the work all through its life. This principle is demonstrated by the open hydroelectric system.