Consider a double-stranded DNA segment representing a transcription unit. Strand A has 3' 5' polarity and Strand B has 5' 3' polarity. If Strand B acts as the coding strand, identify the regions located at its 5' end and 3' end respectively.

Step-by-step solution

According to the convention in defining a transcription unit, the reference is made with respect to the polarity of the coding strand, which has 5' 3' polarity. The promoter is located towards the 5' end (upstream) of the coding strand. The terminator is located towards the 3' end (downstream) of the coding strand. Therefore, the regions at the 5' and 3' ends of Strand B are the promoter and terminator respectively. The operator is a component of an operon, not a basic transcription unit. Answer: Promoter and Termi