The base in DNA that specifies the first base in the RNA transcript is called a(n) ____ and is numbered ____.
A) promoter; −5
B) enhancer; −35
C) transcription start site; 0
D) transcription start site; +1
E) promoter complex; +5

Question

Quizplus · Accepted Answer

The base in DNA that specifies the first base in the RNA transcript is called the transcription start site (TSS) and is numbered +1. Therefore, the correct answer is D - transcription start site; +1. A promoter is a sequence of DNA that initiates transcription whereas an enhancer is a DNA sequence that can increase transcription levels, both of which are not specific to the first base in the RNA transcript. The other answer options are incorrect because the numbering system for nucleotide positions starts from the TSS, so the correct numbering for the first base is +1, not -5 or +5.

The Base in DNA That Specifies the First Base in the RNA