What is the iron-containing protein in red blood cells that binds oxygen?

What is the iron-containing protein in red blood cells that binds oxygen?

• A. Hemoglobin
• B. Myoglobin
• C. Ferritin
• D. Hematocrit

Answer: (A)

The iron-containing protein in red blood cells that binds oxygen is hemoglobin. Hemoglobin has four subunits, each with a heme group that contains iron. This iron reversibly binds one oxygen molecule, so in the lungs oxygen joins to iron and is carried through the bloodstream, then released to tissues where it’s needed. This reversible binding is essential for efficient oxygen transport. For context, myoglobin also binds oxygen but is found in muscle tissue and serves as a stored oxygen reserve there, not in red blood cells. Ferritin stores iron inside cells, not oxygen, and hematocrit is a lab value that indicates the proportion of red blood cells in blood rather than a protein.

The iron-containing protein in red blood cells that binds oxygen is hemoglobin. Hemoglobin has four subunits, each with a heme group that contains iron. This iron reversibly binds one oxygen molecule, so in the lungs oxygen joins to iron and is carried through the bloodstream, then released to tissues where it’s needed. This reversible binding is essential for efficient oxygen transport.

For context, myoglobin also binds oxygen but is found in muscle tissue and serves as a stored oxygen reserve there, not in red blood cells. Ferritin stores iron inside cells, not oxygen, and hematocrit is a lab value that indicates the proportion of red blood cells in blood rather than a protein.