In E.coli replication starts at :

Options

A. Replication fork
B. Template strand
C. Promoter region
D. Origin of replication

Answer

To solve the question regarding where replication starts in E. coli, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: E. coli is a prokaryotic organism, which means it has a simpler structure compared to eukaryotic cells.

2. **Identify Key Terms**: The question mentions several terms: replication fork, template strand, promoter region, and origin of replication. We need to determine which of these is the correct starting point for replication in E. coli.

3. **Define the Origin of Replication**: In prokaryotes like E. coli, replication begins at a specific location known as the "Origin of Replication" (often abbreviated as "ori"). This is a designated site on the DNA where the replication process is initiated.

4. **Consider Other Options**:
- **Replication Fork**: This is the area where the DNA is unwound and replication occurs, but it is not the starting point.
- **Template Strand**: This refers to the strand of DNA that is used as a template for synthesizing the new strand, not where replication starts.
- **Promoter Region**: This is involved in the initiation of transcription, not replication.

5. **Conclusion**: Since E. coli has only one origin of replication, the correct answer to the question is "Origin of Replication".

### Final Answer:
In E. coli, replication starts at the **Origin of Replication**.

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