Circular DNA is found in

Options

A. Bacteria
B. Chloroplast
C. Mitochondria
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding Circular DNA**: Circular DNA is a form of DNA that is shaped like a circle. This type of DNA is typically found in certain organisms, particularly prokaryotes and some organelles in eukaryotic cells.

2. **Bacteria**: Bacteria are prokaryotic organisms that possess a single, circular DNA molecule. This DNA is not enclosed within a nucleus and is directly in contact with the cytoplasm. The size of bacterial genomes can vary widely, ranging from approximately 130 kilobase pairs (kbp) to 14 megabase pairs (mbp).

3. **Chloroplasts**: Chloroplasts are organelles found in eukaryotic cells, specifically in plants and some protists. They contain their own circular DNA, often referred to as chloroplast DNA (ctDNA). This DNA is involved in the synthesis of proteins necessary for photosynthesis and other functions.

4. **Mitochondria**: Mitochondria are also membrane-bound organelles found in eukaryotic cells. They contain their own circular DNA, known as mitochondrial DNA (mtDNA). This DNA plays a crucial role in energy production and cellular respiration.

5. **Conclusion**: Since circular DNA is found in bacteria, chloroplasts, and mitochondria, the correct answer to the question "Circular DNA is found in?" is "all of these."

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