[Campbell Biology P.392] Based on the provided figures and text, how does the initiation of ... | Practice Question

Based on the provided figures and text, how does the initiation of transcription in eukaryotes primarily differ from that in bacteria?

  • A: Eukaryotic RNA polymerase directly binds to the promoter, while bacterial RNA polymerase requires transcription factors.
  • B: In eukaryotes, transcription factors must bind to the DNA before RNA polymerase II can bind, whereas in bacteria, RNA polymerase directly binds to the promoter.
  • C: Eukaryotic transcription always results in a usable mRNA immediately, unlike bacterial transcription which requires processing.
  • D: The TATA box is present only in bacterial promoters, not eukaryotic ones.

Explanation

Figure 17.9 and its accompanying text explicitly state that in eukaryotic cells, transcription factors mediate the initiation of transcription by RNA polymerase II, which involves several transcription factors binding to the DNA, including one recognizing the TATA box, before RNA polymerase II can bind. Conversely, Figure 17.8 implies a more direct binding of RNA polymerase to the promoter in bacteria. The text also mentions that in bacteria, the RNA transcript is immediately usable, while in eukaryotes, it must first undergo processing.