Chloroplasts are the organelles other than the nucleus and mitochondria that contain their own DNA. Chloroplasts are found in plants and certain forms of protists. Their DNA and ribosomes are located in the stroma.
Chloroplasts are the site of photosynthesis in plants and contains the green pigment known as chlorophyll. Their DNA are large circular molecules which contain approximately 120 genes, depending on the plant species. Much of the structure of the chloroplast is similar to mitochondria and like mitochondria, it is believed that chloroplasts evolved from bacteria. The gene sequence of several types of chloroplast DNA have been sequenced, including tobacco and liverwort.