The morphology, function and activity of a cell are all dependent on the proteins it expresses.
Proteins perform a huge variety of roles.
The key to appreciating how different proteins function in these different ways lies in an understanding of protein structure. The following topics very briefly introduce some of the key concepts relating to protein structure and function, and accompany a collection of interactive 3D molecular models of various biologically active proteins considered in the 2nd year BMedSc Cell Biology module . Depending on the nature and arrangement of the amino acids present, different parts of the molecule form secondary structure such as the alpa helices or beta sheets shown below. Further folding and reorganisation within the molecule results in higher order or tertiary structure . Different regions of the protein, often with distinct functions, may form structuraly distinct domains .