Question

Given below are two statements about transport of \(\text{O}_{2}\) and \(\text{CO}_{2}\).
Statement (I): In the alveoli, where \(\text{ppO}_{2}\) is high and \(\text{ppCO}_{2}\) is low, the oxygen binds to haemoglobin.
Statement (II): In the alveoli under low \(\text{ppCO}_{2}\), hydrogen ion and bicarbonate ions recombine under the influence of the enzyme carbonic anhydrase and release \(\text{CO}_{2}\).
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

In alveoli, high oxygen pressure favours oxyhaemoglobin and low carbon dioxide pressure reverses bicarbonate formation.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
Gas transport follows partial pressures. Alveoli have high oxygen pressure and low carbon dioxide pressure.

Step 2: Check Statement I
High oxygen pressure and low carbon dioxide pressure favour binding of oxygen with haemoglobin to form oxyhaemoglobin. This statement is correct.

Step 3: Check Statement II
Where carbon dioxide pressure is low, carbonic anhydrase drives the reaction backwards. Hydrogen ions and bicarbonate ions combine to give \(\text{CO}_{2}\), which diffuses out into the alveoli. This statement is correct.

Step 4: Conclude
Both statements are correct.

Final Answer:
Both Statement I and Statement II are correct. \[ \boxed{\text{(A) }\text{Both Statement (I) and Statement (II) are correct.}} \]