Mitochondria and chloroplasts are the other organelles besides the nucleus that contains ___

Mitochondria and chloroplasts are unique organelles that contain their own DNA, which is a key reason why they are essential to cellular function and energy production. Unlike typical cellular organelles, these organelles possess a double membrane structure and have their own genetic material separate from the nuclear DNA of the cell. This DNA is often circular and resembles bacterial DNA, supporting the endosymbiotic theory, which suggests that these organelles originated from free-living prokaryotes that were engulfed by ancestral eukaryotic cells.

While it's true that both mitochondria and chloroplasts also have two membranes, the question specifically requires identifying what they have that is not common among all organelles; DNA is indeed unique to a select group of organelles, while almost all organelles have some form of membrane structure. Chlorophyll is specific to chloroplasts, so it would not apply to both organelles mentioned. Therefore, the presence of DNA is the distinctive characteristic that sets mitochondria and chloroplasts apart in this context.