What they do is they catalyze all of their different types of biological processes and reactions that take place inside our cells. And without the enzymes catalyzing the reactions, cellular processes would essentially hold to a rate that would make life impossible, at least in the way that we know life today. So the first thing you have to know about enzymes is an enzyme is a biological molecule that catalyzes speeds up the rate of reactions. Now, in our discussion on hemorrglobin, we mentioned one important enzyme, namely carbonic anhydrase. And we said that it was carbonic anhydrase that essentially speeds up and allows the conversion of carbon dioxide into its polar form, namely bicarbonate ions. And this is exactly what allows us to actually store the carbon dioxide inside our blood plasma.