Question:
Read the following passage and answer the questions that follow :
The process of copying genetic information from template strand of DNA into RNA is called transcription. It is mediated by RNA polymerase. Transcription takes place in the nucleus of eukaryotic cells. In transcription, only a segment of DNA and only one of the strands is copied into RNA.
(b) (ii) Mention the two additional processes which hnRNA needs to undergo after splicing to become functional.
Read the following passage and answer the questions that follow :
The process of copying genetic information from template strand of DNA into RNA is called transcription. It is mediated by RNA polymerase. Transcription takes place in the nucleus of eukaryotic cells. In transcription, only a segment of DNA and only one of the strands is copied into RNA.
(b) (ii) Mention the two additional processes which hnRNA needs to undergo after splicing to become functional.
Show Hint
Think of what is added to the two ends of the spliced RNA.
Updated On: Oct 22, 2026
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Solution and Explanation
Step 1: Recall the steps after transcription:
In eukaryotes the primary transcript (hnRNA) is processed before it leaves the nucleus.
Splicing is the first step. Two more changes are then made to the spliced RNA.
Step 2: Name the two additional processes:
Capping: an unusual nucleotide, methyl guanosine triphosphate, is added to the \( 5^{\prime} \) end of the hnRNA.
Tailing: about 200-300 adenylate residues (poly A) are added to the \( 3^{\prime} \) end.
Step 3: Result:
After splicing, capping and tailing, the hnRNA is a fully processed, functional mRNA.
It is then transported out of the nucleus for translation.
Final Answer:
The two additional processes are capping at the \( 5^{\prime} \) end and tailing (poly A addition) at the \( 3^{\prime} \) end.
In eukaryotes the primary transcript (hnRNA) is processed before it leaves the nucleus.
Splicing is the first step. Two more changes are then made to the spliced RNA.
Step 2: Name the two additional processes:
Capping: an unusual nucleotide, methyl guanosine triphosphate, is added to the \( 5^{\prime} \) end of the hnRNA.
Tailing: about 200-300 adenylate residues (poly A) are added to the \( 3^{\prime} \) end.
Step 3: Result:
After splicing, capping and tailing, the hnRNA is a fully processed, functional mRNA.
It is then transported out of the nucleus for translation.
Final Answer:
The two additional processes are capping at the \( 5^{\prime} \) end and tailing (poly A addition) at the \( 3^{\prime} \) end.
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