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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
Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.
Explain the process of transcription in Eukaryotes.
Explain the process of making heterogeneous nuclear RNA (hnRNA) into a fully functional mRNA in eukaryotes. Where does this process occur in the cell?
Answer the following question.
Construct and label a transcription unit from which the RNA segment given below has been transcribed. Write the complete name of the enzyme that transcribed this RNA.
Methyl guanosine triphosphate is added at 5' end of hn-RNA in a process of ______.
If the base sequence of a codon in mRNA is 5'-AUG-3', the sequence of tRNA pairing with it must be ______.
The amino acid attaches to the tRNA at its ______.
Ribozyme is a/an:
Which of the following pair lack the unit membrane?
Refer the given diagram. What does it represent?
Identify the correct statement.
What are the functions of poly-A “tail” in a mature on RNA?
What is the consensus sequence of the –10 region (Pribnow Box) in bacterial promoters?
In which direction does RNA polymerase move along the template strand during bacterial transcription elongation?
During bacterial transcription elongation, what happens to the two DNA strands as RNA polymerase moves forward?
How many DNA strands are read simultaneously by RNA polymerase during bacterial transcription?
Which mechanism of transcription termination in bacteria does not require a protein factor?
Which single enzyme in bacteria synthesizes all types of RNA (mRNA, tRNA, and rRNA)?
