Question

In: Biology

Which of the following is a form of hemoglobin in which iron is in the Fe+3...

Which of the following is a form of hemoglobin in which iron is in the Fe+3 state and can be reduced back to a Fe+2 state by a RBC pathway?

a. Sulfhemoglobin

b. Deoxyhemoglobin

c. Oxyhemoglobin

d. methemoglobin

Solutions

Expert Solution

The answer is methemoglogin (d)

Methemoglobin is a form of oxygen-carrying metalloprotein hemoglobin in which the iron in the form of Fe+3. Methemoglobin cannot bind oxygen, unlike oxyhemoglobin. In the human blood trace amount of methemoglobin is normally produced spontaneously. The NADH-dependent enzyme methemoglobin reductase converts methemogloin back to hemoglobin, which will bind iron in the form of Fe+2. The presence of methemoglobin causes a disorder known methemoglobinemia, which the iron in the form of Fe+3 and has decreased capacity to bind oxygen. This will lead to an overall reduced ability of red blood cells to release oxygen to tissues.


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