How is the bulk of carbon dioxide transported in blood?
A) as carbonic acid in the plasma
B) as bicarbonate ions in plasma after first entering the red blood cells
C) chemically combined with the heme portion of hemoglobin
D) chemically combined with the amino acids of hemoglobin as carbaminohemoglobin in the red blood cells

Question

Quizplus · Accepted Answer

The majority of carbon dioxide is transported in blood as bicarbonate ions formed by the reaction of carbon dioxide with water in red blood cells, which are then transported in the plasma. A small amount is also transported as carbaminohemoglobin (choice D), but this is not the primary mode of transport. Carbonic acid (choice A) is only a temporary intermediate in the formation of bicarbonate ions.

How Is the Bulk of Carbon Dioxide Transported in Blood