What are proteins primarily composed of?

Proteins are primarily composed of hydrogen, oxygen, nitrogen, and carbon, with nitrogen being a distinguishing element that sets proteins apart from carbohydrates and fats. The building blocks of proteins are amino acids, which contain an amino group (–NH2) that includes nitrogen. Each amino acid also contains carbon, hydrogen, and oxygen atoms, contributing to the overall structure of proteins.

The focus on hydrogen, oxygen, and nitrogen in this answer highlights the essential components that make up amino acids, which are linked together through peptide bonds to form proteins. This contrasts with other macronutrients such as carbohydrates and fats, which do not contain nitrogen and are composed of different combinations of these elements. Understanding the composition of proteins is fundamental to grasping their role in biological processes, such as muscle repair, enzyme function, and immune response.