The functional equivalent of the TATA binding protein in prokaryotes is:
A)a sigma subunit.
B)a holoenzyme.
C)the Rho factor.
D)TFIID.
E)hairpin loops.

Question

Quizplus · Accepted Answer

In prokaryotes, the functional equivalent of TATA binding protein is a sigma subunit, which is a component of the RNA polymerase holoenzyme. The sigma subunit recognizes the promoter sequence in prokaryotic DNA, just as TBP recognizes the TATA box in eukaryotic DNA. Therefore, choice A is the best answer. Holoenzyme (choice B) refers to the RNA polymerase complex itself, and is not specifically related to promoter recognition. The Rho factor (choice C) is involved in transcription termination in prokaryotes, not promoter recognition. TFIID (choice D) is a eukaryotic transcription factor that includes TBP, among other subunits, and is not present in prokaryotes. Hairpin loops (choice E) are secondary structures formed in RNA, and are not directly involved in promoter recognition.

The Functional Equivalent of the TATA Binding Protein in Prokaryotes