(a) : The 1992 Nobel prize for medicine was awarded to Edmond H. Fischer and Edwin J. Krebs for their work concerning reversible protein phosphorylation as biological regulation mechanism. The winners of 1992 Noble prize in Physiology and Medicine discovered a 'life switch" that turns on and off a variety of biological functions of the cell, including the breakdown of fats and the generation of chemical energy. The prize - winning discovery is known as "reversible protein phosphorylation".