Which of the following facts does NOT provide evidence for the endosymbiotic theory?

• A. Mitochondria and chloroplasts have double membranes.
• B. Mitochondria and chloroplasts are involved in protein synthesis in the cytoplasm.
• C. Mitochondria and chloroplasts replicate independently of the cell cycle.
• D. Mitochondria and chloroplasts contain their own circular DNA.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the endosymbiotic theory. This theory suggests that mitochondria and chloroplasts originated from free-living prokaryotic cells that were engulfed by ancestral eukaryotic cells, forming a symbiotic relationship.
2. Step 2: Review the evidence supporting the endosymbiotic theory. Key evidence includes: (a) Mitochondria and chloroplasts have double membranes, which is consistent with the engulfing process. (b) They contain their own circular DNA, similar to prokaryotic cells. (c) They replicate independently of the cell cycle, resembling prokaryotic division.
3. Step 3: Analyze the statement 'Mitochondria and chloroplasts are involved in protein synthesis in the cytoplasm.' This does not align with the endosymbiotic theory because protein synthesis in the cytoplasm is a general cellular function and does not specifically relate to the unique characteristics of mitochondria and chloroplasts.
4. Step 4: Compare the statement 'Mitochondria and chloroplasts are involved in protein synthesis in the cytoplasm' with the other options. The other options directly support the endosymbiotic theory, while this statement does not provide evidence for it.
5. Step 5: Conclude that the statement 'Mitochondria and chloroplasts are involved in protein synthesis in the cytoplasm' does NOT provide evidence for the endosymbiotic theory, as it does not highlight the unique features of mitochondria and chloroplasts that support their prokaryotic origin.