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 ...
George Mason: Who Wrote the Bill of Rights? George Mason was a delegate from the state of Virginia, who is credited alongside James Madison with the passing â and subsequent creation â of the Bill of Rights; Mason is noted for his refusal to sign the Constitution.