Protein molecules are composed of long chains of?

Protein molecules are composed of long chains of amino acids. Amino acids are arranged in a linear sequence to form a protein or polypeptide chain. The structure is held together by peptide bonds that happen during protein biosynthesis.

Protein molecules serve many functions in many living organisms. Among others, they can be found transporting ions and molecules across membranes in the cell; they provide cells its unique shape; and they are also the building blocks of hormones in the body.