Physiological chemistry is the chemistry of the organs and tissues of the body and of the various physiological processes incident to life. Physiological chemistry is essentially the precursor to modern biochemistry. In the nineteenth century, physiological chemistry dealt primarily with extracellular chemistry, such as the chemistry of digestion and other body fluids. Modern biochemical methods have allowed a much broader study including the chemistry of proteins and nucleic acids.
Biochemistry is the study of the chemical processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules.
en.wikipedia.org/wiki/Biochemistry.