Mode of DNA replication in E. coli is :-

Options

A. Conservative and unidirectional
B. Semi conservative and unidirectional
C. conservative and bidirectional
D. Semi conservative and bidirectional

Answer

### Step-by-Step Solution:

1. **Understanding DNA Replication**:
- DNA replication is the process by which a cell makes an exact copy of its DNA. This is essential for cell division and occurs in both prokaryotes (like E. coli) and eukaryotes.

2. **Types of DNA Replication**:
- In eukaryotes, DNA replication is described as **semi-conservative** and **semi-discontinuous**.
- **Semi-conservative** means that each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.
- **Semi-discontinuous** refers to the fact that one strand (the leading strand) is synthesized continuously, while the other strand (the lagging strand) is synthesized in short segments called Okazaki fragments.

3. **DNA Replication in Prokaryotes**:
- In prokaryotes, such as E. coli, DNA replication is also **semi-conservative**.
- However, it is primarily **continuous** and **bi-directional**.
- **Bi-directional** means that replication occurs in two directions away from the origin of replication.

4. **Conclusion**:
- Therefore, the mode of DNA replication in E. coli is **semi-conservative**, **bi-directional**, and **continuous**.

### Final Answer:
The mode of DNA replication in E. coli is semi-conservative, bi-directional, and continuous.

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