The oxidation of the Hb molecule's iron ions to the ferric state (Fe3+) results in which of the fol-lowing?
1. Form of anemia called sickle cell anemia
2. Formation of methemoglobin (metHb)
3. Inability of metHb to bind with O2
a. 1 and 2 only
b. 1 and 3 only
c. 2 and 3 only
d. 1, 2, and 3
ANS: C
metHb is an abnormal form of the molecule in which the heme-complex normal ferrous iron ion (Fe2+) loses an electron and is oxidized to its ferric state (Fe3+). In the ferric state, the iron ion cannot combine with O2.
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