Hemoglobin is a protein in red blood cells that carries oxygen from the lungs to the rest of the body. Its function depends on its iron-containing heme groups. Here’s how it works:
- Oxygen binding in the lungs – In the lungs, oxygen molecules attach to the iron (Fe²⁺) in the heme part of hemoglobin. Each hemoglobin can carry four oxygen molecules.
- Transport through the blood – Hemoglobin carries the bound oxygen safely through the bloodstream without it dissolving into the plasma.
- Oxygen release in tissues – When hemoglobin reaches tissues that need oxygen, it releases the oxygen, which then diffuses into cells for energy production.
- CO₂ transport back to lungs – Hemoglobin also helps carry some carbon dioxide back to the lungs for exhalation.
In short, hemoglobin acts like a delivery truck, picking up oxygen in the lungs, transporting it through the blood, and unloading it where the body needs it most.