Question

These factors are favourable for the formation of oxyhaemoglobin:
I. High ${pCO}_2$
II. High ${pO}_2$
III. Lesser H$^+$ concentration and lower temperature
IV. Higher H$^+$ concentration and higher temperature

• A. II and III
• B. I and IV
• C. III and IV
• D. I and III

Hint:

Remember, the Bohr effect plays a crucial role in the release of oxygen from haemoglobin in tissues. Conversely, high ${pO}_2$ and low H$^+$ concentration favour the binding of oxygen to haemoglobin in the lungs.

Answer 1

The Correct Option is A

Step 1: Oxyhaemoglobin formation occurs when oxygen binds to haemoglobin in the lungs. For this to happen, the following conditions are favourable: 
Step 2: High ${pO}_2$ (II): A high partial pressure of oxygen is crucial for the formation of oxyhaemoglobin, as it promotes the binding of oxygen to haemoglobin in the lungs. 
Step 3: Lesser H$^+$ concentration and lower temperature (III): Lower hydrogen ion concentration (which results in higher pH) and cooler temperatures facilitate the binding of oxygen to haemoglobin, as this reduces the tendency of haemoglobin to release oxygen. 
Step 4: On the other hand, high ${pCO}_2$ (I) and higher H$^+$ concentration and higher temperature (IV) favour the release of oxygen from oxyhaemoglobin, as these factors promote the Bohr effect, where haemoglobin releases oxygen more readily in tissues with high CO2 levels, high temperature, and low pH. 
Conclusion: The factors that favour the formation of oxyhaemoglobin are high ${pO}_2$ (II) and lesser H$^+$ concentration and lower temperature (III).