Which of the following hemoglobin variants cannot combine reversibly with oxygen?
I. reduced hemoglobin
II. oxyhemoglobin
III. methemoglobin
IV. carboxyhemoglobin

Question

Quizplus · Accepted Answer

Methemoglobin and carboxyhemoglobin cannot combine reversibly with oxygen. Methemoglobin is formed when iron in hemoglobin is oxidized to the ferric state and cannot bind with oxygen. Carboxyhemoglobin is formed when carbon monoxide binds with hemoglobin and the binding is so strong that it does not release oxygen. Reduced hemoglobin and oxyhemoglobin can both reversibly bind with oxygen.

Which of the Following Hemoglobin Variants Cannot Combine Reversibly with Oxygen