Biology Module 1 - 1.aspects of biochemistry 1.8 explain the meanings of the terms primary, secondary, tertiary and quaternary structures of proteins

1.8 explain the meanings of the terms primary, secondary, tertiary and quaternary structures of proteins


Diagrams of structures



source

1. Primary structure - sequence of amino acids and the most basic structure of a polypeptide                                                                                                                                                                                                                                                     
2. Secondary structure - alpha helix which is a right handed                                    helix                                                                                  - beta pleated sheet which is folded back and forth to form a flat sheet or contorted bed                                                                                                                                                                                                                         
3. Tertiary structure - this is further folding of the polypeptide to give a 3D complex shape. This structure has both alpha helix and beta pleated sheets in the one single polypeptide                                                                                                                                                                                                                                                                     
4. Quaternary structure - this is two or more polypeptides which associate to form a protein. The polypeptides can be identical or different but are two or more separate polypeptides which are 'bundled' together