Breathing and Exchange of Gases Question 9
9. Bulk of carbon dioxide $(CO_2)$ released from body tissues into the blood is present as
[2011M]
(a) bicarbonate in blood plasma and RBCs
(b) free $CO_2$ in blood plasma
(c) 70% carbamino- haemoglobin and 30% as bicarbonate
(d) carbamino-haemoglobin in RBCs
Show Answer
Answer : a
Hints & Solution
(a) 70% to 75% $CO_2$ is transported as primary buffer of the blood bicarbonate ion $(HCO_3)$ in blood plasma. When $CO_2$ diffuses from tissues into blood then it is acted upon by the enzyme carbonic anhydrase.
