Molecular biology is the study of molecular underpinnings of the process of replication, transcription, translation and cell function. It is a branch of science that investigates biological activity at the molecular level, particularly the interactions between various systems of a cell and the structure, function and regulation of proteins and nucleic acids essential to life. It overlaps with biochemistry and genetics with particular focus on DNA, RNA and protein biosynthesis.
In more recent years, there has been a strong shift in interest from DNA to RNA, whose functions range from serving as a temporary working copy of DNA to actual structural and enzymatic functions.