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प्रश्न
Give an account of post transcriptional modifications of a eukaryotic mRNA.
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उत्तर
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′-end of hnRNA. In tailing, adenylate residues (200 - 300) are added at 3′-end in a template-independent manner. It is the fully processed hnRNA, now called mRNA, that is transported out of the nucleus for translation.
Process of Transcription in Eukaryotes
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संबंधित प्रश्न
Explain the process of making heterogeneous nuclear RNA (hnRNA) into a fully functional mRNA in eukaryotes. Where does this process occur in the cell?
If the base sequence of a codon in mRNA is 5'-AUG-3', the sequence of tRNA pairing with it must be ______.
In eukaryotes, the process of processing of primary transcript involves ______.
On the ribosome, mRNA binds ______ and two sites in the ______ for subsequent amino acids to bind to be close enough to each other for the formation of a peptide bond.
Ribozyme is a/an:
The most abundant type of RNA in the cell is ______.
The most likely method, used to determine the structural details of the cell organelle is ______.
Sigma factor is a component of ______.
A ribozyme is an:
The exon part of mRNA has code for ______
Identify the correct statement.
Identify the correct statement.
What are the functions of methylated guanasine cap?
What are the functions of poly-A “tail” in a mature on RNA?
Observe the segment of mRNA given below.
(a) Explain and illustrate the steps involved to make fully processed hnRNA?
(b) Gene encoding RNA Polymerase I and III have been affected by mutation in a cell. Explain its impact on the synthesis of a polypeptide, stating the reasons.
During bacterial transcription elongation, what happens to the two DNA strands as RNA polymerase moves forward?
Which mechanism of transcription termination in bacteria does not require a protein factor?
