The element central to the heme group that binds oxygen is which?

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Multiple Choice

The element central to the heme group that binds oxygen is which?

In the heme group, oxygen binding is driven by a single iron atom nestled in the porphyrin ring. This iron is in the ferrous state (Fe2+) and can reversibly attach one O2 molecule, forming a Fe2+-O2 complex that enables oxygen uptake in the lungs and release in tissues. If the iron is oxidized to ferric state (Fe3+), it no longer binds O2 effectively, which is why conditions that raise Fe3+ reduce oxygen transport. Magnesium is the central metal in chlorophyll, not in heme, so it doesn’t serve as the oxygen-binding site in blood. Zinc and copper participate in various enzymes and proteins, but they do not act as the primary oxygen-binding center in human hemoglobin or myoglobin.

In the heme group, oxygen binding is driven by a single iron atom nestled in the porphyrin ring. This iron is in the ferrous state (Fe2+) and can reversibly attach one O2 molecule, forming a Fe2+-O2 complex that enables oxygen uptake in the lungs and release in tissues. If the iron is oxidized to ferric state (Fe3+), it no longer binds O2 effectively, which is why conditions that raise Fe3+ reduce oxygen transport.

Magnesium is the central metal in chlorophyll, not in heme, so it doesn’t serve as the oxygen-binding site in blood. Zinc and copper participate in various enzymes and proteins, but they do not act as the primary oxygen-binding center in human hemoglobin or myoglobin.

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