Body Fluids and Circulation Question 11
11. What is true about RBCs in humans?
[2010]
(a) They carry about 20-25 per cent of $CO_2$.
(b) They transport 99.5 per cent of $O_2$.
(c) They transport about 80 per cent oxygen only and the rest 20 per cent of it is transported in dissolved state in blood plasma.
(d) They do not carry $CO_2$ at all.
Show Answer
Answer : a
Hints & Solutions
(a) Blood transports oxygen from respiratory organs to the tissue cells and also transports carbon dioxide from the tissue cells to the respiratory membrane. About 97% of oxygen is transported by RBCs in the blood while the remaining three percent of oxygen is carried in a dissolved state through plasma. Nearly 20-25% of carbon dioxide is transported by RBCs whereas 70% is carried as bicarbonate. About 7% of $CO_2$ is carried in dissolved state through plasma.
