Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.…
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: During the transportation of gases, about $20-25$ percent of $\mathrm{CO}_2$ is carried by Haemoglobin as carbamino-haemoglobin.
Reason R: This binding is related to high $\mathrm{pCO}_2$ and low $\mathrm{pO}_2$ in tissues.
In the light of the above statements, choose the correct answer from the options given below.
A is true but $R$ is false.
A is false but $R$ is true.
Both A and R are true and R is the correct explanation of A .
Both A and R are true but R is NOT the correct explanation of A .
Solution
The correct answer is option (3) as nearly $20-25$ precent of $\mathrm{CO}_2$ is transported by RBCs whereas 70 percent of it is carried as bicarbonate. About 7 percent of $\mathrm{CO}_2$ is carried in a dissolved state through plasma.
The binding of $\mathrm{CO}_2$ with haemoglobin is related to the partial pressure of $\mathrm{CO}_2 . \mathrm{pO}_2$ is a major factor which could affect this binding. When $\mathrm{pCO}_2$ is high and $\mathrm{pO}_2$ is low as in the tissues, more binding of $\mathrm{CO}_2$ occurs. Percentage of a gas transported depends upon its partial pressure. If partial pressure decreases, the transportation of gases also decrease with haemoglobin. So, Reason is the correct explanation of Assertion.