Ribonucleic Acid (RNA)

Knowledge of the chemistry of a living cells nucleus is thought to have begun in 1869, when the Swiss biochemist Friedrich Miescher (1844–1895) separated the nucleus from the other parts of the cell and isolated phosphorus–containing substances that we now call nucleic acids, the molecular substrate of the genetic code. It was later found that there were two kinds of nucleic acids, according to the bases that were identified. One type of nucleic acid was obtained from animal glands and later called DNA, while the other type, obtained from yeast cells, was called RNA. It was not until the 1940s that biochemists realized that both DNA and RNA are present in all living cells, whether plant or animal. Although DNA Molecular structure of RNA. Illustration by Hans & Cassidy. Courtesy of Gale Group. is present only in the nucleus of the cell, RNA is found in both the nucleus as well as the cytoplasm.

Many key discoveries lead to the identification of the source, structure and function of an organism's genetic material. In 1950, American biochemist Erwin Chargaff (1929–1992) determined that the arrangement of nitrogenous bases in DNA was variable, however, the specific bases seemed to occur in a one–to–one ratio (now known as complementary base pairing). In 1953, British James D. Watson (1928–) and American Francis H. C. Crick (1916–) deciphered the molecular structure of DNA using research from their own lab as well as vital results obtained from colleagues. They determined the structure of DNA to be a double helix with two long molecular threads or strands, twisted around each other. American chemist Marshall Nirenberg (1927–) was later credited with translating the code of life and was awarded the Nobel Prize in 1968. He demonstrated that RNA could be translated into protein. Initially, it was thought that there was only one kind of RNA, but other types of RNA with specialized functions have since then been discovered.