Protein Structures Are Determined by Their Components and How They Are Assembled

Proteins are made up of long chains of amino acids called polypeptides.

Stick and ball model of the amino acid Glycine.
Glycine, one of the 20 naturally occurring amino acids

Chemical interactions cause segments of the polypeptide chains to fold into α-helices or β-sheets.

A red corkscrew shaped segment, an orange relatively flat segment with an arrow at one end, a green segment with an arrow at one end and a twist at the other, and a yellow spiral segment.
Examples of helices and sheets. Within a protein, these are linked by additional amino acids to form a polypeptide chain

The polypeptide chains fold into a three-dimensional shape or structure.

Many different colored and shaped helices and sheets connected with amino acids to form an example protein.
Example of a three-dimensional structure for the protein alcohol dehydrogenase