Proteins are large, complex molecules that are made in the polar, watery environment of the cell. They are made by joining amino acids together in a particular sequence. Because each of the 20 amino acids is different in shape and chemical property, proteins fold up into amazingly complex 3-dimensional shapes following basic principles of chemistry.

Proteins are large, complex molecules that are made in the polar, watery environment of the cell. They are made by joining amino acids together in a particular sequence. Because each of the 20 amino acids is different in shape and chemical property, proteins fold up into amazingly complex 3-dimensional shapes following basic principles of chemistry.

In the interactive Jmol window to the right, a single beta-globin protein is shown in a "spacefilled format". In this format, each atom of this 146-amino acid protein is shown as a color-coded sphere;