Question

Explain the structure, kinds and functions of Ribonucleic acid.

Answer 1

Ribonucleic acid or RNA is of 3 types

1. Messenger RNA or mRNA

It is always single-stranded without any base pairing. Structural components of mRNA are-

CAP(at 5' end) , non-coding region 1, Initiation codon AUG, Coding region, Termination codon, Non-coding region 2 and poly-A sequence (at 3'end ).

Function- mRNA convey genetic information from DNA of chromosomes to the ribosomes, where it takes part in protein synthesis.

2. Ribosomal RNA or rRNA

This RNA is constituent of ribosomes and developed from the nucleolar organiser region of chromosomes in eukaryotes.

It plays a structural and catalytic role during translation. This RNA is seen as compact rod or coil or in the form of extended regions but the structure actually depends upon various factors like ionic strength, pH, temperature etc.

3. Transfer RNA or tRNA

tRNA contains five arms each with a loop and a stem which are:

Acceptor arm(without a loop), D-arm, Anticodon arm, Variable arm and TΨU arm.

The function of tRNA is to align the required amino acid according to the nucleotide sequence of mRNA.

It also carries the activating enzyme of amino acid.