The linkage that joins two adjacent nucleotides in RNA is
(a) phosphate ester (b) phosphodiester
(c) phosphate anhydride (d) N-glycoside
(b) A phosphodiester bond is a group of strong covalent bonds between the phosphorus atom in a phosphate group and two other molecules over two ester bonds. Phosphodiester bonds are central to all life on Earth as they make up the backbone of the strands of DNA. In DNA and RNA, the phosphodiester bond is the linkage between the 3' carbon atom and the 5' carbon of the ribose sugar.