question_answer 16)

  A nucleoside differs from a nucleotide. It lacks the (a) base                                                (b) sugar                              (c) phosphate group      (d) hydroxyl group

Answer:

                  (c) A nitrogenous base is attached to the pentose sugar by an N-glycosidic linkage to form a nucleoside, i.e., Nucleoside=Nitrogen base Pentose sugar. When a phosphate group is attached to the 5'-OH of a nucleoside through phosphodiester linkage, a nucleotide is formed, i.e., Nucleotide = Nitrogen base+ Pentose sugar +Phosphate (PO4). So, a nucleoside differs from a nucleotide as it lacks the phosphate group.