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BIO NMDCAT Ribonucleic acid (RNA)
nmdcat.online July 3, 2026

88. A mutation in the gene encoding the sigma factor subunit of prokaryotic RNA polymerase would directly impair the

A. Elongation of the nascent RNA transcript chain
B. Recognition and binding to the promoter sequence
✓
C. Cleavage of the polycistronic mRNA transcript
D. Addition of the terminal amino acid to the tRNA

📝 Explanation

The sigma subunit is a transient initiation factor that grants the core prokaryotic RNA polymerase structural specificity to bind promoters.

📖 Additional Information

  • Elongation of the nascent RNA transcript chain
  • Recognition and binding to the promoter sequence
  • Cleavage of the polycistronic mRNA transcript
  • Addition of the terminal amino acid to the tRNA

The sigma subunit is a transient initiation factor that grants the core prokaryotic RNA polymerase structural specificity to bind promoters.

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