As soon as we add even a tiny amount of those H plus ions as soon as even a tiny number of those H plus ions are mixed into our solution. Notice what happens to the curve. The curve drops from seven all the way to two very drastically immediately following the addition of H plus ions. And what that tells us is our cells and the outside portion of cells, even though it does consist of water, it cannot be pure water because pure water isn't a good system because it can prevent these drastic changes in PH from actually taking place. So the curve shows that adding acid to pure water creates an immediate and drastic change in PH. And if the cells of our body and the blood and the various biological systems in our body consisted of pure water and nothing else, then any acid based reaction that took place inside our body would change the PH abruptly destroying the many different types of biological molecules by disrupting their molecular structure.