BIO 203 Lecture Notes - Lecture 17: Respiratory Pigment, Partial Pressure, Hemoglobin
8 Dec 2017
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Across pulmonary capillaries; partial pressure gradients established. Blood leaving lungs in high o2 and low co2. Partial pressure of o2 relatively low, and co2 relatively high. Blood leaving tissues relatively low in o2 and high in co2. Blood fills up on o2 and dump off co2. Reversibly bind oxygen with loading and unloading at physiologically appropriate po2. Exist as various biochemical compounds in different organisms and tissues in different developmental stages. 90% if the o2 transported in the blood is associated with a respiratory pigment. Hemoglobin: fe2+ based, tetrameric, 4 goblin protein monomers (2 alpha and 2 beta in adult humans, each monomeric hb subunit binds one o2 molecule, contained in erythrocytes. Cooperativity leads to sigmoid shaped o2 binding curve. P50 describes the oxygen partial pressure at 50% of the pigment is oxygenated. At low po2 only one o2 is bound to hemoglobin. When one o2 is bound to hemoglobin, the protei(cid:374)"s affi(cid:374)ity for o2 is greater.
