<prompt> 1st carbon of pentose sugar of nucleic acid joinsN-9 of pyrimidineN-1 of pyrimidineN-1 of purineN-8 of purine  <response>: The sugars and phosphates in nucleic acids are connected to each other in an alternating chain sugar-phosphate backbone through phosphodiester linkages. In conventional nomenclature, the carbons to which the phosphate groups attach are the 3;-end and the 5;-end carbons of the sugar. This gives nucleic acids directionality, and the ends of nucleic acid molecules are referred to as 5;-end and 3;-end. The nucleobases are joined to the sugars an N-glycosidic linkage involving a nucleobase ring nitrogen N-1 for pyrimidines and N-9 for purines and the 1; carbon of the pentose sugar ring.Ref: Harper;s Biochemistry; 30th edition 