Carbon dioxide is transported in the blood in the following ways

Carbon dioxide is transported in the blood in the following ways

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Carbon dioxide is transported in the blood in the following ways:  A small amount of CO 2  (5 percent) is carried in the plasma as a dissolved  gas.  Some CO 2  (10 percent) binds to Hb in red blood cells, forming  carbaminohemoglobin (HbCO 2 ). (The CO 2  binds to the amino acid portion of  hemoglobin instead of to the iron portion.)  Most CO 2  (85 percent) is transported as dissolved bicarbonate ions  (HCO 3 ) in the plasma. The formation of HCO 3 , however, occurs in the red  blood cells, where the formation of carbonic acid (H 2 CO 3 ) is catalyzed by the  enzyme carbonic anhydrase, as follows: 
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Unformatted text preview: CO 2 + H 2 O H 2 CO 3 H + + HCO 3 Following their formation in the red blood cells, most H + bind to hemoglobin molecules (causing the Bohr effect) while the remaining H + diffuse back into the plasma, slightly decreasing the pH of the plasma. The HCO 3 ions diffuse back into the plasma as well. To balance the overall increase in negative charges entering the plasma, chloride ions diffuse in the opposite direction, from the plasma to the red blood cells (chloride shift)....
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