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What is the difference between a nucleoside and a nucleotide ? |
Answer» Solution :A nucleoside is formed when 1- position of a pyrimidine (cytosine , thymine or URACIL) or 9-position of a purine (guannine or adenine) base is ATTACHED to C-1 of sugar (ribose or deoxyribose ) by a `beta`-linkage. Thus , in general , nucleosides may be represented as : Sugar -Base. For EXAPLE , STRUCTURE (I) represents a nucleoside.  A nucleoside contains all the THREE basic components of nucleic acids ,i.e., a phosphoric acid group , a pentose sugar and a nitrogenous base. These are obtained by estertification of `C_(5)'-OH` group of the pentose sugar by phosphoric acid. Thus , in general , a nucleotide is represented as `"Sugar -Base" -O-overset(O)overset(||)underset(O)underset(||)P-OH` For example , structure (II) represents a nucleotide. |
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