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Biochemistry · Transcription: RNA polymerase II
Sample itemAt a protein-coding gene, TBP within TFIID binds the TATA box. TFIIB and TFIIF then bring in which enzyme to complete the preinitiation complex?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
D. RNA polymerase II
The general transcription factors assemble at the core promoter in order, and TFIIF escorts the polymerase to it. TFIIH then unwinds DNA and phosphorylates the tail domain, allowing promoter escape. Primase and DNA polymerases belong to replication.
Option by option
A. DNA polymerase epsilon
DNA polymerase epsilon takes part in leading-strand DNA synthesis.
B. Primase
Primase makes short RNA primers for DNA replication and is not part of this complex.
C. Poly(A) polymerase
Poly(A) polymerase acts at the 3-prime end after transcription and is not part of initiation.
D. RNA polymerase II (correct)
Correct. TFIIF delivers this enzyme to the promoter to complete the preinitiation complex.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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