Define the following terms : (3 marks)
(i) Nucleotide (ii) Anomers (iii) Essential amnio acids
(i) Nucleotide : A nucleotide contains all the three basic components of nucleic acids, i.e. a
phosphoric acid group, a pentose sugar and a nitrogenous base. These are formed by esterifi-
cation of of the sugar of the nucleoside with phosphoric acid.
Structure of Nucleotide :
(ii) Anomers : A pair of stereoisomers which differ in configuration only around are called
anomers. Two isomers are said to be anomers if the isomerisation in the molecule is at first
(iii) Essential amino acids : Amino acids which the body cannot synthesize are called essential
Example : Valine, leucine etc. Therefore they must be supplied in diet.