Hans Adolf Krebs

Hans Adolf Krebs was born in Germany on 25 August 1900 and trained as a physician and biochemist before the war pushed him to Britain. He spent years tracing how cells metabolize nutrients, first cracking the urea cycle - the body's way of disposing nitrogen waste - then the citric acid cycle, the central engine of cellular respiration that allows oxygen-breathing organisms to harvest vastly more energy than fermentation ever could. That second discovery, often called the Krebs cycle, earned him the Nobel Prize in Physiology or Medicine in 1953. Later, working with Hans Kornberg, he identified the glyoxylate cycle, a variant pathway in plants and microbes. He spent his final academic years at Oxford, retiring in 1967 and dying there in 1981.