Biochemistry is the branch of science that deals with the study of the chemical processes and substances that occur within living organisms. It combines the principles and techniques of biology and chemistry to understand the molecular mechanisms underlying various biological functions and processes.

Biochemists investigate the structure, function, and interactions of biological molecules such as proteins, carbohydrates, lipids, and nucleic acids. They study how these molecules are synthesized, modified, and degraded within cells, as well as the chemical reactions and pathways that govern these processes.