They possess their own DNA and ribosomes.
Explanation
Mitochondria are double-membrane-bound organelles found in the cytoplasm of eukaryotic cells. They are primarily responsible for cellular respiration and the production of energy in the form of ATP (Adenosine Triphosphate). A unique characteristic of mitochondria, shared only with plastids (in plants), is their semi-autonomous nature.
Detailed Analysis:
- They can survive outside the cell in pond water. is Incorrect: While mitochondria have evolutionary origins related to bacteria (Endosymbiotic Theory), they are integral parts of the eukaryotic cell and cannot survive or replicate independently outside the cellular environment (e.g., in pond water).
- They possess their own DNA and ribosomes. is Correct: Mitochondria possess their own single circular DNA molecule and ribosomes (70S type). This genetic machinery allows them to synthesize some of their own proteins, making them semi-autonomous organelles. This feature distinguishes them from most other organelles like the Golgi apparatus or Endoplasmic Reticulum, which lack their own genetic material.
- They lack a membrane covering unlike other organelles. is Incorrect: Mitochondria are bound by a double membrane envelope (outer and inner membranes). Organelles that lack a membrane covering include ribosomes and centrosomes.
- They are found only in animal cells and not in plant cells. is Incorrect: Mitochondria are present in both plant and animal cells. While plant cells also contain chloroplasts for photosynthesis, they still require mitochondria for cellular respiration.
Key Takeaway:
Mitochondria and Plastids are distinct from other organelles because they are semi-autonomous, possessing their own circular DNA and ribosomes, which enables them to synthesize specific proteins required for their function.