Final answer:
Carbon dioxide is transported in the blood through dissolution, binding to hemoglobin, or conversion into bicarbonate. The majority is transported as bicarbonate. It first diffuses into red blood cells and is converted into bicarbonate, which is then transported across the membrane, re-enters the red blood cells at the lungs, and is converted back into carbon dioxide.
Step-by-step explanation:
Carbon dioxide can be transported through the blood via three methods: dissolution directly into the blood, binding to hemoglobin, or converted into bicarbonate. The majority of carbon dioxide is transported as part of the bicarbonate system. Carbon dioxide diffuses into red blood cells and is converted into bicarbonate with the help of carbonic anhydrase. This bicarbonate is then transported across the membrane into the plasma, and at the pulmonary capillaries, it re-enters the red blood cells and is converted back into carbon dioxide, which can be expelled from the body.