Molecular Genetics

DNA carries hereditary info, controls cellular process and tightly packed into chromosomes

DNA can pass down characterstics to the next generation, as stated in Griffith's Transforming Principle.

The theory suggests that some eukaryotic cell organelles (mitochnondria & chloroplast) are evolved from free living prokaryotes.

This explains why Mitochondria and Chloroplast has their own hereditary information.