[Campbell Biology P.424] Based on Figure 18.11 and its description, which of the following s... | Practice Question

Based on Figure 18.11 and its description, which of the following statements accurately describe the roles of the components involved in the formation of an active transcription initiation complex in eukaryotes?

  • A: Activator proteins directly bind to the TATA box within the promoter to initiate transcription.
  • B: Enhancers are DNA sequences that can be located far from the gene but influence its transcription through DNA bending.
  • C: Mediator proteins serve as a bridge, connecting activators to general transcription factors and RNA polymerase II.
  • D: RNA polymerase II binds directly to the distal control elements to begin RNA synthesis.
  • E: The TATA box is a critical component of the enhancer, serving as the primary binding site for activators.

Explanation

According to Figure 18.11 and the accompanying text, enhancers are DNA sequences that can be located far from the gene hundreds or even thousands of nucleotides away and influence transcription through DNA bending mediated by a DNA-bending protein. Mediator proteins act as a crucial link, connecting activator proteins bound to enhancers with general transcription factors and RNA polymerase II to form the transcription initiation complex. Activator proteins bind to distal control elements on the enhancer, not the TATA box. The TATA box is located within the promoter. RNA polymerase II binds to the promoter indirectly via other factors, not directly to distal control elements.