Haemoglobin is classified as a conjugated protein because it
- A. consists of four identical polypeptide chains
- B. contains only amino acids joined by peptide bonds
- C. is made in the bone marrow rather than the liver
- D. contains a non protein haem group attached to its polypeptide chains
Explanation
A conjugated protein is a protein permanently joined to a non protein prosthetic group, and in haemoglobin each of the four chains carries an iron containing haem that actually binds the oxygen. Without the haem the globin protein alone could carry nothing. Glycoproteins and lipoproteins are conjugated in the same sense, with a carbohydrate or lipid group instead.