Assertion: Mitochondrial DNA is similar to prokaryotic DNA.
Reason: Mitochondria are thought to have evolved from the prokaryotes.

Options

A. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
B. If both Assertion and Reason are true and the Reason is not
the correct explanation of the Assertion.
C. If Assertion is true but the Reason is false.
D. If both Assertion and Reason are false.

Answer

To solve the assertion-reason question, we will analyze both the assertion and the reason step by step.

### Step 1: Analyze the Assertion
**Assertion:** Mitochondrial DNA is similar to prokaryotic DNA.

- Mitochondrial DNA (mtDNA) is indeed similar to prokaryotic DNA. Both types of DNA are circular and double-stranded.
- Additionally, mitochondrial DNA is not associated with histone proteins, which is a characteristic of prokaryotic DNA (also known as prochromosome). This lack of histones is a significant similarity.

### Step 2: Analyze the Reason
**Reason:** Mitochondria are thought to have evolved from the prokaryotes.

- This statement is supported by the endosymbiotic theory, which suggests that mitochondria originated from free-living prokaryotic cells that were engulfed by ancestral eukaryotic cells.
- This evolutionary relationship explains why mitochondrial DNA shares similarities with prokaryotic DNA.

### Step 3: Conclusion
- Both the assertion and the reason are true.
- The reason provides a correct explanation for the assertion, as the evolutionary origin of mitochondria from prokaryotes accounts for the similarities in their DNA.

### Final Answer
Since both the assertion and reason are true, and the reason explains the assertion, the correct option is A.

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