Extra chromosomal DNA molecules present in bacterial cells are

Options

A. plasmids
B. Nucleoid
C. Ribosomes
D. Chromatophores

Answer

To answer the question, "Extra chromosomal DNA molecules present in bacterial cells are," we need to analyze the options provided and identify the correct one.

### Step-by-Step Solution:

1. **Understanding the Question**: The question is asking for the type of extra chromosomal DNA found in bacterial cells. Extra chromosomal DNA refers to DNA that is not part of the chromosomal DNA.

2. **Analyzing Option 1 - Plasmids**:
- Plasmids are small, circular, double-stranded DNA molecules that exist independently of chromosomal DNA in bacteria.
- They often carry genes that provide bacteria with advantageous traits, such as antibiotic resistance.
- Therefore, this option is correct.

3. **Analyzing Option 2 - Nucleotides**:
- Nucleotides are the building blocks of DNA and RNA, not extra chromosomal DNA themselves.
- They do not exist as independent DNA molecules in bacterial cells.
- Thus, this option is incorrect.

4. **Analyzing Option 3 - Ribosomes**:
- Ribosomes are cellular structures that synthesize proteins and are not DNA molecules.
- They do not contain any genetic material, making this option incorrect.

5. **Analyzing Option 4 - Chromatophores**:
- Chromatophores are pigment-bearing cells found in certain organisms, not in bacterial cells.
- They are not related to DNA and therefore this option is also incorrect.

6. **Conclusion**: Based on the analysis of all options, the correct answer is **Option 1 - Plasmids**.

### Final Answer:
Extra chromosomal DNA molecules present in bacterial cells are **Plasmids**.

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