The promoter site and the terminator site for transcription are located at :a)3 (downstream) end and 5 (upstream) end, respectively of the transcription unitb)5 (upstream) end and 3 (downstream) end, respectively of the transcription unitc)the 5 (upstream) end of the transcription unitd)the 3 (downstream) end of the transcription unitCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

The promoter site and the terminator site for transcription are located at the 5' (upstream) end and 3' (downstream) end, respectively, of the transcription unit.

Promoter Site:
The promoter site is a specific DNA sequence that initiates the transcription process. It is located upstream of the transcription unit, which means it is found towards the 5' end of the DNA molecule. The promoter site provides a binding site for RNA polymerase, the enzyme responsible for transcription. It contains specific sequences of nucleotides recognized by the RNA polymerase, such as the TATA box in eukaryotes. The binding of RNA polymerase to the promoter site marks the initiation of transcription.

Terminator Site:
The terminator site is a specific DNA sequence that signals the end of transcription. It is located downstream of the transcription unit, which means it is found towards the 3' end of the DNA molecule. The terminator site contains sequences that cause the RNA polymerase to dissociate from the DNA and release the newly synthesized RNA molecule. This allows the RNA molecule to be processed and eventually translated into a protein in the case of protein-coding genes.

Transcription Unit:
The transcription unit refers to the DNA segment that is transcribed into RNA. It includes the promoter site, the coding region, and the terminator site. The coding region contains the actual sequence of nucleotides that will be transcribed and translated into a functional protein or a functional RNA molecule.

Summary:
In summary, the promoter site, which marks the initiation of transcription, is located at the 5' (upstream) end of the transcription unit, while the terminator site, which marks the end of transcription, is located at the 3' (downstream) end of the transcription unit. These sites play crucial roles in the regulation and control of gene expression.

Similar Class 12 Doubts

Assertion: A transcription unit in DNA defined primarily by the three regions in the DNA, viz, a promoter, the structural gene and a terminator. Reason: The promoter is located Lowards S'end of structural gene and it is a DNA sequence that provides binding site for RNA polymerase.?

Assertion: The terminator is located towards 3' end of the coding strand and it usually defines the end of the process of transcription. Reason : During transcription, the DNA strand which runs in 5' - 3' is called the template strand?

Transcription unit three regions what are they?

Why the both strands of DNA are not copied during transcription.?

Which of the following enzyme binds to the promoter and initiates the process of transcription?

Top Courses for Class 12

Suggested Free Tests

Related Content

Schools

Competitive Examinations

Quick Access Links

Technical Exams