What is the name of the protein molecule that transports oxygen in red blood cells?

The protein molecule responsible for transporting oxygen in red blood cells is hemoglobin. Hemoglobin is a complex protein made up of four subunits, each containing an iron atom that can bind to oxygen molecules. This binding allows hemoglobin to carry oxygen from the lungs to the tissues throughout the body, where it is needed for cellular respiration and energy production.

Furthermore, hemoglobin's structure allows it to efficiently pick up oxygen in areas of high concentration (like the lungs) and release it in areas of low concentration (such as tissues with high metabolic activity). This property is crucial for maintaining the body's oxygen levels and overall metabolic function.

Other proteins listed in the options have different roles. Myoglobin, for instance, is found in muscle tissue and helps store oxygen for muscle use, but it is not responsible for oxygen transport in the bloodstream. Albumin is a protein found in blood plasma that helps maintain osmotic pressure and transport various substances, but it does not transport oxygen. Collagen is a structural protein in connective tissues and has no role in oxygen transport at all. Thus, hemoglobin is specifically designed and adapted for the essential function of carrying oxygen in red blood cells.