In biology, the term is sometimes used in the context of a chemical reaction, in particular to describe the energy source for the chemical synthesis of ATP. More generally, however, it is used to characterize the inclined tendency of solutes to simply diffuse across a membrane, a process involving no chemical transformation.
Another way to describe osmosis... which is primarily described as a balancing between the internal and external cell environment.
Reading the whole article and doing a little research the acid/alkaline balancing principles that moreless speaks of becomes more clear.