Give an account of post transcriptional modifications of a eukaryotic  $m-RNA$ .

Vedclass pdf generator app on play store
Vedclass iOS app on app store

The primary transcripts ($hn$-$RNA$) contain both the exons and the introns and are non-functional. Hence, it is subjected to a process called splicing where the introns are removed and exons are joined in a defined order. Intron is the portion of gene which is transcribed but not translated. In prokaryotes $hnRNA$ is absent so splicing in not required. $hnRNA$undergoes additional processing called as capping and tailing.

In capping an unusual nucleotide (methyl guanosine triphosphate) is added to the $5^{\prime}$-end of $hnRNA$. In tailing, adenylate residues ($200$-$300$) are added at $3^{\prime}$-end in a template independent manner. It is the fully processed $hnRNA$, now called $mRNA$, that is transported out of the nucleus for translation.

968-s125

Similar Questions

What is meant by monocistronic $mRNA$

One strand of the given segment of $DNA$ codes for $mRNA$ having the sequence $AUC, GCG, UCA$ needed for synthesis of proteins. The strand by which $DNA$ molecule will be responsible for the above $mRNA$ sequence is

$A$ : $5\;S rRNA$ and surrounding protein complex provides binding site of $tRNA$.
$R$ : $tRNA$ is soluble $RNA$ with unusual bases

In eukaryotes $mRNA$ transcribed is called

A geneticist isolates a gene for a specific traits under study, she also isolate the corresponding $mRNA$. Upon comparison, the $mRNA$ is found to contain $1,000$ fewer bases than the $DNA$ sequence. Did the geneticist isolate the wrong $DNA$?