DNA of E.Coli is :

Options

A. ds circular
B. ss circular
C. ds Linear
D. ss Linear

Answer

To solve the question regarding the DNA of E. coli, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**:
- E. coli stands for Escherichia coli, which is a type of bacteria.

2. **Determine the Structure of E. coli DNA**:
- E. coli has a unique DNA structure that is different from eukaryotic organisms. The DNA is circular.

3. **Count the Base Pairs**:
- The approximate number of base pairs in the E. coli genome is about 4.6 x 10^6 base pairs.

4. **Characterize the DNA**:
- The DNA of E. coli is double-stranded, which means it consists of two strands that form a double helix.

5. **Understand the Arrangement**:
- The DNA is organized into a structure known as the nucleoid, as bacteria do not have a defined nucleus.

6. **Identify the Type of DNA**:
- The DNA in E. coli is classified as B-type DNA, which is the most common form of DNA found in living organisms.

7. **Summarize the Key Features**:
- E. coli DNA is:
- Circular
- Double-stranded (dsDNA)
- Approximately 4.6 million base pairs
- Organized in a nucleoid structure
- Right-handed double helix with about 10 nucleotides per turn

8. **Select the Correct Answer**:
- Based on the characteristics identified, the correct answer to the question is that E. coli DNA is double-stranded and circular.

### Final Answer:
The DNA of E. coli is double-stranded (dsDNA) and circular.

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