Molecular biology is a field of science concerned with studying the chemical structures and processes of biological phenomena that connect the basic units of life, molecules. It is a branch that studies the molecular basis of biological activity showing how living organisms perform the functions of life. The field of molecular biology is concentrated specially on nucleic acids and proteins. Macromolecules that are essential to life processes and how these molecules communicate and behave within cells. Molecular biology primarily focusses on the understanding of structures, functions, and internal communications intra and inter for individual cells, all of which targets new drugs, diagnose disease, and better understand cell physiology. Clinical research and medical therapies based on molecular biology are dealt as gene therapy whereas molecular biology or cell biology is now referred to as molecular medicine in medicine.