Origin of Life

All organisms rely on the same kinds of organic (carbon-containing) compounds; the same 20 amino acids combine to make up all the enormous diversity of proteins occurring in living things. DNA and RNA, furthermore, are essential to all life. Into these molecules is encoded the information needed to synthesize specific proteins from amino acids. One class of proteins, known as enzymes, acts to regulate the activity of nucleic acids and other biochemical functions essential to life. Enzymes do this by greatly increasing the speed of (i.e., catalyzing) specific chemical reactions. Other proteins provide structure for cells, regulate the passage of ions through the cell membrane, and perform numerous other functions. Nucleic acids and proteins are so universally essential to modern life-forms that many scientists assume that either they, or closely related precursor compounds, were present in the first life-forms.