Dr. George Palade, shown in a 1966 file photo, won a Nobel Prize in Physiology or Medicine in 1974 for his discoveries on the structural and functional organization of the cell. (Anthony Camerano/Associated Press)

Dr. George Palade, who won a Nobel Prize in 1974 for his work isolating and identifying cell structure and who helped create one of the leading cell biology programs in the U.S. at the University of California, San Diego, has died.

He was 95.

Palade died Tuesday, the university announced.

He was born in Romania, earned his medical degree there and went to the United States in 1946.

During the 1950s and '60s, Palade took advantage of new techniques to understand the structure of the cell, its function and chemistry.

Using those techniques, he identified the function of, among other things, mitochondria, the power plants of the cell, and ribosomes, the protein-making machinery.

"George Palade was not only one of the leading scientists of his era, but was a pioneer in modern cell biology, using electron microscopy to study and describe subcellular structures for the first time," said Dr. David A. Brenner, UCSD's vice-chancellor for health sciences.

Working with Albert Claude at what is now known as Rockefeller University in New York, Palade began developing ways to separate cellular components.

Palade also discovered and studied the endoplasmic reticulum, a system of folded membranes that permeates the cytoplasm of cells and provides a large surface area for chemical reactions.

He showed that the endoplasmic reticulum is a vital component of all types of body cells except the mature red blood cell.

The work of Palade and his fellow scientists earned them the 1974 Nobel Prize in Physiology or Medicine.

In 1973, he left Rockefeller for Yale University, where he was chairman of the new department of cell biology. In 1990, he moved to UCSD, where he became the founding dean for scientific affairs. He retired in 2001 but remained a consultant.

Among his many other honours were the National Medal of Science, the Albert Lasker Award for Basic Medical Research and the Louisa Gross Horwitz Prize.