Branch of biology that shares the methods of physics to the study of biological processes and structures is defined as bio-physics. Bio-physicists conduct research concerned with understanding the connections between the various systems of a cell, including the interactions between DNA, RNA and protein biosynthesis, as well as how these interactions are controlled. It is a multifaceted science using methods of, and theories from, physics to study biological systems. Biophysics reserves all scales of biological organization, from the molecular scale to entire organisms and ecosystems.