Молекулы связываются с железом в гемовой группе, облегчая транспорт. Cross-sectional diagram of a red blood cell showing hemoglobin, with alpha (? ) and beta (? ) polypeptide chains and heme groups containing iron ions (Fe²? ). Oxygen molecules bind to iron in the heme group, facilitating transport and release. Insets detail oxygen binding and transport processes from lungs to tissues. Vibrant red and blue denote oxygenated and deoxygenated states, respectively, with chemical structures illustrating the biochemical interactions. The image provides a clear visualization of hemoglobin's role in oxygen transport within the human body.