As I'm not so eloquent with words, I'm copying another forum: The statement, "one molecule away from plastic" is meaningless. Both inorganic and organic compounds can differ radically even if the stereoisometry (left-right handedness) is different. Even with basic inorganic compounds, one atom can make all the difference. Take H20 and H2O2. Water and Hydrogen Peroxide. One is required by mammals to sustain life, the other when consumed in the same manner will kill them in 30 minutes. Another example is the stereoisomers Quinine and Quinidine. Quinine is a harmless compound used to treat malaria and is even included in some brands of tonic water. Quinidine, on the other hand is used to treat heart arrhythmias and can be toxic in high doses. Finally, organic chemistry is mother nature's true mad scientist. Take testosterone and estrogen. One can readily convert to another by a single one-step reaction via aromatase enzyme. 19 carbons and you can grow a beard. 18 carbons and you can give birth.