RBCs and Hemoglobin

• Developing red blood cell loses all intracellular organelles not involved with its primary functions: oxygen and carbon dioxide transport
• Hemoglobin (Hb) molecules make up more than 95 percent of the RBC's proteins
• Hemoglobin is responsible for the cell's ability to transport oxygen and carbon dioxide
• Heme, a nonprotein pigment that forms a ring
• Each heme unit holds iron, forming oxyhemoglobin
• Blood that contains RBCs filled with oxyhemoglobin is bright red
• A hemoglobin molecule whose iron is not bound to oxygen is called deoxyhemoglobin, which appears dark red