Dr. Claude discovered mitochondria, which store energy, and Dr. Palade discovered ribosomes, the protein factories within cells. The Karolinska Institute, in awarding the Nobel, credited the three scientists as having founded the field of modern cell biology.

Christian René de Duve was born on Oct. 2, 1917, in Thames Ditton, England, near London. His parents were Belgians who had fled to England during World War I. When the war ended, his family returned to Belgium and settled in Antwerp. Dr. de Duve received his medical degree from the Catholic University of Louvain in 1941.

During World War II he was a medic in the Belgian Army. After German forces captured his unit in France, he managed to escape and made his way back to Belgium.

Dr. de Duve soon resumed his medical training at the Catholic University of Louvain’s Cancer Institute while pursuing graduate studies in chemistry. He wrote a book on insulin, the subject of his thesis. He received his doctorate in chemistry in 1945.

Intent on a career in research, he set off for labs in Sweden and the United States to study biochemistry. Over the next two years, he studied under Hugo Theorell at the Medical Nobel Institute in Stockholm and Carl Cori and Gerty Cori at Washington University in St. Louis, all of whom would later receive Nobel Prizes. Dr. de Duve returned to the Catholic University of Louvain in 1947 to teach physiological chemistry. He became a full professor in 1951.

His research continued to focus on insulin, a hormone involved in the regulation of blood sugar. Working with liver cells, he used Dr. Claude’s recently developed centrifugal techniques to separate cell parts. Centrifuges are spinning devices that speed up the rate at which particles settle in liquid. Dr. Claude’s technique called for using a pestle to break open cells before placing them in the centrifuge.

In one experiment, Dr. de Duve noticed that acid phosphatase, an enzyme he had included as a control, was less active than in earlier experiments in which he had used an electric blender instead of a pestle to break up cells. He was intrigued and pursued his chance finding.