Question

why the higher percentage of co2 transported by water of RBC as compared to water of plasma ? also give the equation of this process.

Answer 1

Carbon dioxide has the ability to attach to hemoglobin molecules. That is why its higher percentage is transported by water of RBCs as compared to water of plasma.

Answer 2

Carbon dioxide $\mathrm{(CO_2)}$ has a high affinity for hemoglobin present in the RBCs or erythrocytes. Majority of the $\mathrm{(CO_2)}$ (96%-97%) released at the end of cellular respiration is taken up by the RBC, whereas only a small portion of it is taken by the plasma (3%-4%).

This is mainly because $\mathrm{(CO_2)}$ forms a compound (carbaminohemoglobin) with hemoglobin with the help of the enzyme carbonic anhydrase. However, most of the $\mathrm{(CO_2)}$ taken up by RBC binds with water to form bicarbonate.

$\bold{\text{Hemoglobin} + \mathrm{CO}_{2} \rightarrow \text{Carbaminohemoglobin}}$

$\bold{\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{H}_{2} \mathrm{CO}_{3}(\text { bicarbonate })}$