Question

Mitochondria and chloroplasts are believed to be bacterial endosymbionts of cells because

• A. They have their own nucleic acids.
• B. Their membranes resemble those of cyanobacteria.
• C. They do arise de novo.
• D. All of the above.

Answer 1

The correct option is A They have their own nucleic acids.

Mitochondria and Chloroplasts are the only cell organelles other than nucleus coated with double membrane. They have their own DNA and protein synthesizing machinery as well. One explanation for a cell organelle to have its own DNA is that these organelles were separate organisms. The chloroplast was an autotrophic cyanobacteria and the mitochondria was a separate heterotrophic organism which later on became lodged into a eukaryotic cell as endosymbionts.