Aspen Institute. The Aspen Institute is an international nonprofit organization founded in 1950 as the Aspen Institute of Humanistic Studies. The organization is dedicated to fostering enlightened leadership, the appreciation of timeless ideas and values, and open-minded dialogue on contemporary issues.
Nitrogen occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids (DNA and RNA) and in the energy transfer molecule adenosine triphosphate. The human body contains about 3% by mass of nitrogen, the fourth most abundant element in the body after oxygen, carbon, and hydrogen.
One major distinction is between natural and synthetic compounds. Organic compounds can also be classified or subdivided by the presence of heteroatoms, e.g., organometallic compounds, which feature bonds between carbon and a metal, and organophosphorus compounds, which feature bonds between carbon and a phosphorus.