Question

The promoter site and the terminator site for transcription are located at

• A. $3^{\prime }$ (downstream) end and $5^{\prime }$ (upstream) end, respectively of the transcription unit
• B. $5^{\prime }$ (upstream) end and $3^{\prime }$ (downstream) end, respectively of the transcription unit
• C. the $5^{\prime }$ (upstream) end
• D. the $3^{\prime }$ (downstream) end

Answer 1

Answer: (B)

The promoter sequence needs to lie in front of the start site or upstream to it in the $5$' end and the terminator should lie in the $3$' end downstream as transcription proceeds in the $5$' to $3$' direction.
So, the correct answer is, '$5$ (upstream) end and $3$ (downstream) end, respectively of the transcription unit'.