Structural Classification Of RNA

Structural Classification Of RNA: RNA is polymer of ribonucleotides held together by 3`,5`- phospholdiester briges. Although RNA has certain similarity with DNA structure, they have several specific differences.

• Pentose : the sugar in RNA is ribose in contrast to deoxyribose in DNA.
• Pyrimidine : RNA contains the pyrimidine uracil in place of thymine.
• Single strand : RNA is usually a single stranded polynucleotide. This strand may fold at certain places to give a double stranded structure.
• Chargaff’s  rule not obeyed: Due to the single stranded nature there is no specific relation between purine and pyrimidine contents. Thus the guanine content is not equal to cyosine.
• Susceptibility to alkali hydrolysis : alkali can hydrolyse RNA to 2`, 3`-cyclic diesters.  This is possible due to the presence of hydroxyl group at 2` position.
• Orcinol color Raction:  RNAs can be histological indentified by aricinol color reaction due to the presence of ribose.