Biochemical reactions are chemical reactions that take place inside the cells of living beings. As we know, the cells inside a living body are composed of different kinds of molecules. During various cellular processes, these molecules combine with other molecules and undergo transformations in their chemical structure. Such a chemical transformation usually happens in the presence of enzymes, which are nothing but biological catalysts that modify the speed of any biochemical reaction. Biochemical reactions are the reactions that underlie all cellular processes inside our bodies, from digestion and respiration to reproduction. Like any other chemical reaction, existing molecules can get decomposed and new molecules can be synthesized during biochemical reactions. During some biochemical reactions, energy is released, usually in the form of ATP. This can be utilized by the cell to carry out various physiological and metabolic activities. Biochemical reactions follow the natural laws of chemical reactions.