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How does hemoglobin transport oxygen in the blood?

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Peptide — Protein The molecular structure of a peptide (a small protein) consists of a sequence of amino acids.

Hemoglobin is an iron-containing protein found in red blood cells that facilitates the transport of oxygen throughout the body. Each hemoglobin molecule consists of four heme groups, each containing an iron atom capable of binding one oxygen molecule, and a globin group.21

The process relies on the following mechanisms:

Binding and Release: In the lungs, where oxygen pressure is high, oxygen diffuses into red blood cells and binds to the iron atoms in hemoglobin. In tissues where oxygen levels are lower, hemoglobin releases the bound oxygen.13
Cooperativity: Hemoglobin exhibits cooperativity, meaning the binding of an oxygen molecule to one iron site increases the affinity of the remaining sites for oxygen, resulting in a characteristic S-shaped oxygen-dissociation curve.14
Regulatory Factors: The affinity of hemoglobin for oxygen is influenced by the environment. Factors such as pH, carbon dioxide, and 2,3-diphosphoglycerate can decrease oxygen affinity, shifting the curve to the right and promoting oxygen release to tissues during high demand, such as exercise. The effect of pH on this binding is known as the Bohr effect.13