Question

Assertion : In human beings, the respiratory pigment is haemoglobin present in red blood cells.
Reason (R) : Haemoglobin has a very high affinity for carbon dioxide.

• A. Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Oxygen binds to haemoglobin to form oxyhaemoglobin. While some \(CO_{2}\) can bind to it (carbaminohemoglobin), its primary high-affinity role is for Oxygen.

Answer 1

The Correct Option is C

The assertion given is: "In human beings, the respiratory pigment is haemoglobin present in red blood cells." This statement is accurate. In humans, haemoglobin, which is present in red blood cells (RBCs), serves as the respiratory pigment. It is responsible for carrying oxygen from the lungs to the rest of the body and facilitating the return transport of carbon dioxide from the tissues back to the lungs.

The reason provided is: "Haemoglobin has a very high affinity for carbon dioxide." This statement is incorrect. Haemoglobin primarily has a high affinity for oxygen, which allows it to effectively bind and transport oxygen. While haemoglobin can bind carbon dioxide, it does not do so with high affinity compared to oxygen. Carbon dioxide is mainly transported in the blood as bicarbonate ions. Therefore, the reason given is false.

Let's evaluate the options:

• Option 1: "Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A)." – This is incorrect because the reason is false.
• Option 2: "Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A)." – This is also incorrect because the reason itself is false.
• Option 3: "Assertion (A) is true, but Reason (R) is false." – This option is correct because the assertion is true, but the reason is inaccurate.
• Option 4: "Assertion (A) is false, but Reason (R) is true." – This is incorrect as the assertion is true while the reason is false.

In conclusion, the correct answer is: Assertion (A) is true, but Reason (R) is false.