1. Mitochondria: These are responsible for cellular respiration and energy production. They have their own circular DNA molecule, which is separate from the nuclear DNA.
2. Chloroplasts: These are found in plant cells and are responsible for photosynthesis. They also have their own circular DNA molecule, separate from the nuclear DNA.
These organelles are thought to have originated from ancient bacteria that were engulfed by eukaryotic cells, a theory known as the endosymbiotic theory. This is why they have their own DNA and ribosomes, similar to bacteria.
