Here's why:
* Mitochondria and Chloroplasts: These are the organelles most often associated with the term "autonomous". They have their own DNA (mtDNA and cpDNA respectively) and can replicate independently. However, they still depend on the host cell for many essential proteins and other components needed for their function. For example, most of their proteins are encoded by nuclear DNA and translated in the cytoplasm, then imported into the organelle.
* Other Organelles: Other organelles like the endoplasmic reticulum, Golgi apparatus, lysosomes, and peroxisomes do not have their own DNA and cannot replicate independently. They are completely dependent on the host cell for their formation, function, and maintenance.
The Endosymbiotic Theory: The presence of DNA in mitochondria and chloroplasts is explained by the endosymbiotic theory, which proposes that these organelles were once free-living bacteria that were engulfed by eukaryotic cells and established a symbiotic relationship. This theory explains why they have their own DNA and can replicate independently, but it also emphasizes their reliance on the host cell.
In Summary: While mitochondria and chloroplasts can replicate independently, they are not autonomous entities. They still depend on the host cell for many crucial functions, making them integrated parts of the cell's overall system.
