Which statement accurately contrasts prokaryotic and eukaryotic transcription initiation?

• A. Prokaryotic transcription uses RNA polymerase with sigma factor to recognize promoters; Eukaryotic transcription requires transcription factors, promoter elements, chromatin remodeling, and occurs in the nucleus.
• B. Prokaryotic transcription requires promoter elements and transcription factors, with no sigma factor.
• C. Prokaryotic transcription uses RNA polymerase without sigma factor; Eukaryotic transcription uses sigma factor to recognize promoters.
• D. Prokaryotic transcription occurs in the nucleus and uses transcription factors; Eukaryotic transcription occurs in the cytoplasm with no transcription factors.

Answer: (C)

Transcription initiation differs in how the polymerase is guided to promoters. In bacteria, a sigma factor bound to RNA polymerase recognizes promoter sequences, helping the polymerase locate where to start transcription and begin synthesis; this happens in the cytoplasm. In contrast, eukaryotes require general transcription factors to assemble at promoter elements and recruit RNA polymerase II, with chromatin remodeling needed to make the DNA accessible, and transcription occurs in the nucleus with RNA processing afterward. So the accurate description is that prokaryotic transcription uses RNA polymerase with a sigma factor to recognize promoters, while eukaryotic transcription relies on transcription factors, promoter elements, and chromatin remodeling in the nucleus. The alternative mixes up these roles by saying prokaryotes lack sigma factors and that eukaryotes use sigma factors.