Define7 marksChallenge
A biology student is studying the structure of haemoglobin and collagen. Haemoglobin is a globular protein with quaternary structure, consisting of four polypeptide chains (two alpha and two beta), each containing a haem group with an iron ion. Collagen is a fibrous protein made of collagen molecules arranged into fibres. Using the information above and your knowledge, write definitions for the key features of protein structure illustrated by haemoglobin and collagen. Your definitions should cover the different levels of protein organization, the distinction between globular and fibrous proteins, and the significance of the iron ion in haemoglobin's function.