A transcription unit in DNA is primarily comprised of:
(A) A Promoter
(B) Origin of replication
(C) The Structural gene
(D) A terminator
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A), (C) and (D) only
A transcription unit is the stretch of DNA that is transcribed into RNA, with the signals that start and stop it.
(A) A Promoter — Part of it. It lies upstream and gives the binding site for RNA polymerase.
(B) Origin of replication — Not part of it. The ori is where DNA replication starts, not transcription.
(C) The Structural gene — Part of it. It is the stretch actually copied into RNA.
(D) A terminator — Part of it. It lies downstream and marks where transcription ends.
Note: A similar question was also asked in CUET (UG) 2026 on 07-06-2026 (Slot 2) and on 29-05-2026 (Slot 1), and in CUET (UG) 2025 on 23-05-2025 (Slot 2).
NCERT Extract:
Transcription Unit – “A transcription unit in DNA is defined primarily by the three regions in the DNA :
(i) A Promoter
(ii) The Structural gene
(iii) A Terminator There is a convention in defining the two strands of the DNA in the structural gene of a transcription unit.”