What is protein primarily composed of?

Protein is primarily composed of amino acids, which are organic molecules that serve as the building blocks of proteins. Each protein is made up of a specific sequence and combination of amino acids, which determine its structure and function in the body. There are 20 different amino acids that can be combined in various ways to create the diverse range of proteins necessary for life.

Amino acids themselves contain an amino group, a carboxyl group, and a unique side chain that defines each amino acid. These properties allow them to link together through peptide bonds, forming polypeptides that eventually fold into functional proteins.

The other options refer to different macromolecules: polysaccharides are complex carbohydrates made up of sugar molecules, fatty acids are components of lipids (fats), and sugars are simple carbohydrates. Each of these plays different roles in the body but they do not constitute proteins. Understanding the fundamental structure of proteins, including the role of amino acids, is essential in fields like nutrition and biochemistry.