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Resp. Physio
Hemoglobin and Oxygen Transport
Question | Answer |
---|---|
O2 transport | oxygen is transported in blood in two ways: dissolved in plasma (only 1.5% because O2 is poorly soluble in plasma) bound to hemoglobin inside RBCs (98.5% is carried this way) |
Hemoglobin | hemoglobin (Hb) is a protein composed of 4 polypeptide chain subunits each subunit is bound to an iron-containing heme group since iron ions serve as oxygen-binding sites, each hemoglobin can rapidly and reversibly bind 4 oxygen molecules |
Hemoglobin II | a hemoglobin molecule bound with oxygen is called oxyhemoglobin (HbO2) a hemoglobin molecule that has released its oxygen is called deoxyhemoglobin (HHb) |
Hemoglobin and Oxygen Transport | when the first oxygen molecule binds the first iron molecule, the hemoglobin changes shape and the affinity for the other 3 oxygen molecules progressively increases |
Hemoglobin and Oxygen Transport II | similarly, when the first oxygen is unloaded, the affinity for oxygen is decreased and it becomes progressively easier for the other 3 oxygen molecules to dissociate from the hemoglobin |
Hemoglobin and Oxygen Transport III | hemoglobin is fully saturated when all four heme groups are bound to oxygen if fewer than all four heme groups are bound, the hemoglobin is said to be partially saturated |