Ochoa, Severo (1905-1993), a Spanish-born American biochemist shared the 1959 Nobel Prize in physiology or medicine with Arthur Kornberg for discovering an enzyme that can synthesize RNA (ribonucleic acid). Nucleic acids, complex chemicals found in the cells of all living things, play essential roles in cell development and heredity. Ochoa's discovery was one of the linchpins of modern molecular biology.

The youngest son of a lawyer, Ochoa was encouraged to pursue his interest in chemistry by a high school teacher. After completing his undergraduate work at Malaga College (1921), he earned a medical degree from the University of Madrid (1929) in order to ground himself in the life sciences. Never having intended to treat patients, he immediately began a career as a researcher at institutions in Spain, Germany, England, and the United States. In 1945, he joined the faculty of New York University's department of biochemistry and, in 1956, he became an American citizen. He retired from NYU in 1974. He returned to his native Spain in 1985, where he was appointed honorary director of Madrid's Molecular Biology Institute.

Upon settling in the United States in 1940, Ochoa continued his studies of enzymes, which he had begun the previous decade while a researcher in Europe. In 1955, Ochoa discovered in a sewage bacterium, a bacterial enzyme that could synthesize RNA in a test tube. RNA, which is important in the creation of proteins in the cell, transmits the genetic information encoded in DNA. The following year, in collaboration with Wendell Meredith Stanley, a virologist at the University of California, Ochoa applied his discovery by using RNA material to create an artificial virus in a test tube.

In collaboration with other American biochemists, Ochoa helped decipher the code in which RNA is written. His work shed light on the nature of viruses, cell reproduction, protein synthesis, and the continuity of life.