Biochemistry is the science that studies the chemical reactions that take place within organisms. This science combines different elements from biology and chemistry. In the early twentieth century, this knowledge was recognized as a separate science. Biochemists or biochemists study large molecules such as proteins, lipids, and carbohydrates that are important in the metabolic reactions of various organisms and that affect cellular activity. Biochemists, on the other hand, study the structure and function of molecules such as enzymes and DNA.