What is Haemoglobin?

Haemoglobin is a conjugated protein found inside red blood cells (erythrocytes) and is responsible for transporting oxygen from the lungs to all body tissues. It is called a conjugated protein because it contains both a protein part (globin) and a non-protein part (haem group) working together as one functional unit. Each haemoglobin molecule consists of four globin chains, and each chain carries one haem group containing an iron (Fe²⁺) atom at its centre.

• Conjugated Protein: Haemoglobin contains globin (protein) + haem (non-protein iron-containing group), making it a classic conjugated protein
• Conjugated Lipid: A lipid combined with non-lipid molecules, completely unrelated to haemoglobin structure
• Oligosaccharide: A short chain of sugar molecules, has no connection with haemoglobin whatsoever
• Sterol: A subgroup of steroids like cholesterol, entirely different from haemoglobin in structure and function