The four nitrogenous bases that make up the DNA structure are divided into two groups, called purines and pyrimidines. Adenine and guanine are purines, and chemically are double-ringed structures - a five cornered ring and a six cornered ring. They are much larger than pyrimidines.
James Mason (I) (1909â1984) James Mason was a great English actor of British and American films. He was born in Yorkshire, and attended Marlborough and Cambridge, where he discovered acting on a lark, and abandoned a planned career as an architect. Following work in stock companies, he joined the Old Vic under the guidance of Sir Tyrone Guthrie and of Alexander Korda, who ...
John Mason, Died 1694. Julian's account of J. Mason: The known facts of his life are scanty. He was the son of a dissenting minister, and the grandfather of John Mason, the author of A Treatise on Self- Knowledge. He was educated at Strixton School, Northants, and Clare Hall, Cambridge. After taking his M.A., he became curate of Isham; and in 1668, Vicar of Stantenburg, Bucks.