Peter Dennis Mitchell, was a British biochemist who was awarded the 1978 Nobel Prize in chemistry for his discovery of the chemiosmotic mechanism of ATP synthesis. Josiah Willard Gibbs was an American scientist who made important theoretical contributions to physics, chemistry and mathematics. Free energy concept in thermodynamics was given by him and thus known as Gibbs free energy. Daniel Israel Arnon was a Polish born American plant physiologist whose research led to greater insights into the operation of photosynthesis in plants. Melvin Ellis Calvin was an American chemist most famed for discovering the Calvin cycle along with Andrew Benson and James Bassham for which he was awarded the 1961 Nobel prize in Chemistry.