How does transcription initiation differ between prokaryotes and eukaryotes?

How does transcription initiation differ between prokaryotes and eukaryotes?

• A. Prokaryotes use RNA polymerase directly with promoters; eukaryotes require transcription factors and promoter elements (e.g., TATA box) and RNA polymerase II
• B. Prokaryotes require transcription factors; eukaryotes use RNA polymerase directly
• C. Both use the same initiation mechanism
• D. Prokaryotes do not transcribe DNA

Answer: (D)

Transcription initiation is simpler in prokaryotes and more complex in eukaryotes. In prokaryotes, RNA polymerase works with a sigma factor that helps the enzyme recognize promoter sequences directly, so the polymerase can bind the promoter and start transcription without many extra players. In eukaryotes, initiation requires a set of transcription factors that recognize promoter elements (like the TATA box) and assemble a preinitiation complex with RNA polymerase II. This arrangement, along with the need to navigate a chromatin-packed nucleus, makes initiation in eukaryotes a multi-step process that carefully coordinates regulation before transcription can begin.

Transcription initiation is simpler in prokaryotes and more complex in eukaryotes. In prokaryotes, RNA polymerase works with a sigma factor that helps the enzyme recognize promoter sequences directly, so the polymerase can bind the promoter and start transcription without many extra players. In eukaryotes, initiation requires a set of transcription factors that recognize promoter elements (like the TATA box) and assemble a preinitiation complex with RNA polymerase II. This arrangement, along with the need to navigate a chromatin-packed nucleus, makes initiation in eukaryotes a multi-step process that carefully coordinates regulation before transcription can begin.