Biology is all about chemistry. Biological processes are chemical reactions.
A huge amount of chemical reactions occur in the living organisms.
The living organisms have proteins, carbohydrates, lipids (fats) and nucleic acids. Their structure, functions and mechanisms are described in chemical terms.
Metabolism is the name of the set of chemical reactions that transform food into energy and other molecules.
The structure of the biomolecules, their functions, bonds, reactions, the effect of drugs, the defficiency of vitamins and minerals effect, the function of the organs, and more, are complex and can only be understood with an adequate understanding of chemistry.