Organic chemistry is most commonly and simply defined as the chemistry of carbon compounds. Compared with hydrogen and helium, carbon is not an abundant element in the universe, nor in the solar system; but it is an essential element of life. Indeed, four elements: carbon, hydrogen, nitrogen and oxygen make up most of the matter found in living organisms. Trace elements such as sulfur, phosphorous, sodium, potassium and iron, to name a few, also play an important role in the chemistry of life; but it is the unique properties of carbon that pemfits the immense diversity of compounds associated with life. From simple single-carbon compounds such as methane and carbon dioxide to the more complex structures found in vitamins, hormones and enzymes, and ultimately to very large macromolecules like DNA, carbon is the underlying essential structural component...