Although a cell is composed of seventy to ninety percent water, most of the rest of the cell contains carbon-based compounds. DNA, proteins, carbohydrates, and other molecules that distinguish living matter from inanimate material are composed of carbon atoms that are bonded to one another and to atoms of other elements. It is carbon that accounts for the endless diversity of biological molecules. The percentage of major elements of life-P, S, C, H, O and N are quite uniform from the individual to individual. The atoms of organic molecules can be arranged in so many different ways that uniqueness of each organism is ensured.
Carbon atoms are the most versatile building blocks of molecules.
The versatility allows a limited assortment of atomic building blocks, taken roughly the same portions, to be used to build an inexhaustible variety of organic molecules. In the nineteenth century chemist had learned to make many simple compounds in the laboratory by combining elements under the right conditions. Around this time Swedish Chemist Jons Jakob Berzelius first made the distinction between organic compounds, those that seemingly could arise only within living compounds and inorganic compounds. The new discipline of organic chemistry was first built on a foundation of vitalism. Soon chemist began to delve into the foundation of vitalism when they learned to synthesis organic compounds in their laboratories.