The Terminator in transcription unit is located at

Options

A. 3' end downstream of the coding strand
B. 5' end downstream of the coding strand
C. 5' end upstream of the coding strand
D. 3' end upstream of the coding strand

Answer

To answer the question about the location of the terminator in a transcription unit, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Components of a Transcription Unit**:
- A transcription unit consists of three main components: the promoter, the structural gene, and the terminator.

2. **Identify the Role of the Terminator**:
- The terminator is a specific region of DNA that signals the end of transcription. It contains sequences that code for the RNA polymerase binding site and the actual stop point for transcription.

3. **Locate the Terminator in Relation to the Coding Strand**:
- The terminator is located downstream of the coding strand, which means it is found towards the 3' end of the DNA sequence.

4. **Clarify the Directionality**:
- In a transcription unit, the coding strand runs in the 5' to 3' direction, while the template strand runs in the 3' to 5' direction. The terminator is positioned at the 3' end of the coding strand.

5. **Evaluate the Options**:
- Given the options, we can conclude that the terminator is located at the 3' end downstream of the coding strand.

6. **Select the Correct Answer**:
- Based on our analysis, the correct answer is that the terminator is located at the 3' end downstream of the coding strand.

### Final Answer:
The terminator in a transcription unit is located at the **3' end downstream of the coding strand**.

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