Question

In eukaryotic transcription, A. RNA polymerase does not require a template. B. all RNA is synthesized in the nucleolus. C. consensus sequences are the only known promoter elements. D. phosphodiester bond formation is favored because there is pyrophosphate hydrolysis. E. RNA polymerase requires a primer.

Short answer

Answer: Phosphodiester bond formation is favored because there is pyrophosphate hydrolysis.

Step-by-step solution

Option A: RNA polymerase does not require a template

RNA polymerase requires a DNA template to synthesize RNA. This statement is false.

Option B: All RNA is synthesized in the nucleolus

The nucleolus is involved in the synthesis of ribosomal RNA (rRNA), but other types of RNA such as mRNA and tRNA are synthesized elsewhere in the nucleus. Therefore, this statement is false.

Option C: Consensus sequences are the only known promoter elements

In eukaryotic transcription, there are various promoter elements, such as TATA box, CAAT box, and GC-rich sequences. Consensus sequences are essential promoter elements, but they are not the only ones. This statement is false.

Option D: Phosphodiester bond formation is favored because there is pyrophosphate hydrolysis

During RNA synthesis, RNA polymerase catalyzes the formation of phosphodiester bonds between nucleotides, which is energetically favored due to the hydrolysis of pyrophosphate (a byproduct of the reaction). This statement is true.

Option E: RNA polymerase requires a primer

Unlike DNA polymerases, which require a primer to initiate synthesis, RNA polymerase can initiate RNA synthesis without a primer. This statement is false. The correct answer is option D: Phosphodiester bond formation is favored because there is pyrophosphate hydrolysis.