Q.36 Given below are two statements:
Statement I: Messenger RNA capping, polyadenylation and splicing are coupled to transcription in eukaryotes.
Statement II: Transcription and translation are compartmentalized in prokaryotes.
In the light of the above statements, choose the
correct answer from the options given below:
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct
Messenger RNA processing couples to transcription in eukaryotes, while prokaryotes couple transcription and translation spatially.
Both statements accurately reflect molecular biology principles: eukaryotic mRNA maturation occurs co-transcriptionally, and prokaryotes lack nucleus-cytoplasm compartmentalization.
Question Breakdown
Statement I correctly describes how capping (at ~20-30 nt), splicing, and polyadenylation in eukaryotes are functionally coupled to RNA Pol II transcription via its CTD domain. Statement II accurately notes prokaryotes’ lack of compartmentalization, allowing simultaneous transcription-translation on the same mRNA molecule.
Option Analysis
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Both Statement I and Statement II are correct: Correct answer. I reflects co-transcriptional processing; II describes prokaryotic coupling without nuclear barrier.
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Both incorrect: Wrong. Both hold textbook validity.
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I correct, II incorrect: False. Prokaryotes truly lack compartmentalization—polysomes form directly on nascent transcripts.
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I incorrect, II correct: Wrong. Eukaryotic coupling is well-established.
Correct Answer
Both Statement I and Statement II are correct.
Eukaryotic mRNA Processing
Messenger RNA capping, polyadenylation and splicing are coupled to transcription in eukaryotes. The RNA Pol II CTD recruits capping enzymes immediately, splicing factors to exons, and cleavage/poly(A) machinery to AAUAAA signals—all co-transcriptionally for efficiency and quality control.
Prokaryotic Coupling
Transcription and translation are compartmentalized in prokaryotes? No—absence of nucleus means ribosomes bind nascent mRNA directly, enabling coupled processes in cytoplasm. Polycistronic operons exemplify this spatial unity.
Key Differences Table
Feature Eukaryotes Prokaryotes mRNA Processing Coupled to transcription (nucleus) None (direct translation) Transcription-Translation Spatially separated Coupled, non-compartmentalized CTD Role Recruits processing factors Absent (σ70 instead) Exam Strategy
GATE/NEET hallmark: Eukaryotes = temporal/spatial coupling of processing; Prokaryotes = transcription-translation coupling. Both statements test this fundamental contrast perfectly.
Ideal for your molecular biology revision pattern.
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