Iron is a necessary component of which molecule?

Iron is a necessary component of which molecule?

• A. Hemoglobin
• B. Myoglobin
• C. Collagen
• D. Melanin

Answer: (A)

Iron’s role here is its ability to bind oxygen through the heme group. In hemoglobin, iron sits in the heme and reversibly binds one molecule of oxygen per heme unit. This lets red blood cells pick up oxygen in the lungs and deliver it to tissues throughout the body. Myoglobin in muscle also contains iron in a heme group and helps store and release oxygen there, which adds helpful context, but the standout example for a molecule that relies on iron to transport oxygen in the blood is hemoglobin. Collagen is a structural protein and doesn’t incorporate iron as part of its basic structure, and melanin production involves enzymes that use copper rather than iron. So iron is a necessary component of the molecule that carries oxygen in the bloodstream.

Iron’s role here is its ability to bind oxygen through the heme group. In hemoglobin, iron sits in the heme and reversibly binds one molecule of oxygen per heme unit. This lets red blood cells pick up oxygen in the lungs and deliver it to tissues throughout the body. Myoglobin in muscle also contains iron in a heme group and helps store and release oxygen there, which adds helpful context, but the standout example for a molecule that relies on iron to transport oxygen in the blood is hemoglobin. Collagen is a structural protein and doesn’t incorporate iron as part of its basic structure, and melanin production involves enzymes that use copper rather than iron. So iron is a necessary component of the molecule that carries oxygen in the bloodstream.