Oxygen binds to the [tex]\(Fe^{2+}\)[/tex] (ferrous) ion in the heme group of hemoglobin.
Here's a detailed explanation:
1. Hemoglobin is a protein in red blood cells responsible for carrying oxygen from the lungs to the tissues and returning carbon dioxide from the tissues to the lungs.
2. Each hemoglobin molecule is made up of four subunits, and each subunit contains a heme group. Therefore, a single hemoglobin molecule can bind up to four oxygen molecules.
3. Heme Group: The heme group consists of a porphyrin ring which coordinates an iron ion at its center. This iron ion is in the ferrous ( [tex]\(Fe^{2+}\)[/tex] ) oxidation state under normal physiological conditions.
4. Binding of Oxygen: Oxygen binds specifically to the [tex]\(Fe^{2+}\)[/tex] ion in the heme group. When oxygen binds to [tex]\(Fe^{2+}\)[/tex], it forms an octahedral complex where oxygen is the sixth ligand to the iron ion.
Thus, the correct answer is:
- the [tex]\(Fe^{2+}\)[/tex] of the heme.
