Which molecule carries oxygen on red blood cells?

Which molecule carries oxygen on red blood cells?

• A. Hemoglobin
• B. Myoglobin
• C. Fibrinogen
• D. Albumin

Answer: (A)

Oxygen transport on red blood cells is carried primarily by hemoglobin. Hemoglobin is a protein inside red blood cells with four heme groups, each containing iron that binds one oxygen molecule. This lets a single hemoglobin molecule carry up to four oxygen molecules from the lungs to tissues where they’re needed, and release them as blood flows through tissues. Myoglobin, on the other hand, stores oxygen in muscle tissue but isn’t contained in red blood cells, so it doesn’t carry oxygen in the bloodstream. Fibrinogen and albumin are plasma proteins involved in clotting and maintaining blood volume/osmotic balance, not oxygen transport. A small amount of oxygen does dissolve in plasma, but the vast majority is carried bound to hemoglobin.

Oxygen transport on red blood cells is carried primarily by hemoglobin. Hemoglobin is a protein inside red blood cells with four heme groups, each containing iron that binds one oxygen molecule. This lets a single hemoglobin molecule carry up to four oxygen molecules from the lungs to tissues where they’re needed, and release them as blood flows through tissues. Myoglobin, on the other hand, stores oxygen in muscle tissue but isn’t contained in red blood cells, so it doesn’t carry oxygen in the bloodstream. Fibrinogen and albumin are plasma proteins involved in clotting and maintaining blood volume/osmotic balance, not oxygen transport. A small amount of oxygen does dissolve in plasma, but the vast majority is carried bound to hemoglobin.