Each type of protein has its own unique structure and function. The starch and cellulose we previously discussed are polymers of glucose, which in that case, is the monomer. Amino acids are built from a central carbon bonded to four different groups. In the approximately-20 amino acids found in our bodies, what varies is the side chain.
Some side chains are hydrophilic while others are hydrophobic.
Since these side chains stick out from the backbone of the molecule, they help determine the properties of the protein made from them. The chain of amino acids is also known as a polypeptide . Some proteins contain only one polypeptide chain while others, such as hemoglobin, contain several polypeptide chains all twisted together. The sequence of amino acids in each polypeptide or protein is unique to that protein, so each protein has its own, unique 3-D shape or native conformation . If even one amino acid in the sequence is changed, that can potentially change the protein's ability to function.