Class 11 NEET Biology Breathing and Exchange of Gases

(b) : Haemoglobin (Hb) is a conjugated protein. It consists of a basic protein globin joined to a nonprotein group heme. Heme is an iron-porphyrin ring. A mammalian Hb molecule is a complex of 4 heme molecules joined with 4 globin molecules. It is present in RBC, and carries O2 from the lungs to the tissues and transports CO2 from the tissues to the lungs.