How do RBCs carry oxygen?

The oxygen transport in blood is carried out by 2 methods:1. A small amount of oxygen is dissolved in plasma and is transported as dissolved oxygen(typically 2–5 %). But remember this dissolution increases drastically with high partial pressure of oxygen in blood and in hyperbaric states. 2. 95–98% oxygen is transported by reversible binding to the heme moiety of hemoglobin. Hemoglobin is a tetrameric protein each monomer consisting of a iron (heme) group encapsulated by a protein moiety. The Fe(II) in heme binds oxygen reversibly which depends on Po2, pH , temperature etc… These factors play a vital role in release of oxygen and in binding of carbon di oxide to heme in tissues, too