Which of the following factors are favorable for the formation of oxyhaemoglobin ?
I. high `pO_2`
II. low `pCO_2`
III. lesser `H^+` concentration
IV. lower temperature

Options

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

Answer

To determine which factors are favorable for the formation of oxyhemoglobin, let's analyze each option step by step:

1. **High pO2 (Partial Pressure of Oxygen)**:
- The formation of oxyhemoglobin is directly influenced by the availability of oxygen. A high partial pressure of oxygen (pO2) means that there is a greater concentration of oxygen available for hemoglobin to bind. Therefore, this factor is favorable for the formation of oxyhemoglobin.

2. **Low pCO2 (Partial Pressure of Carbon Dioxide)**:
- The presence of carbon dioxide (CO2) affects the binding of oxygen to hemoglobin. A low partial pressure of carbon dioxide (pCO2) promotes the formation of oxyhemoglobin. This is because high levels of CO2 can lead to a decrease in pH (more acidic conditions), which can hinder the binding of oxygen.

3. **Lesser H+ Concentration**:
- The concentration of hydrogen ions (H+) is related to the pH of the blood. A lower concentration of H+ ions corresponds to a higher pH, which is more favorable for the formation of oxyhemoglobin. High levels of H+ ions (low pH) can lead to the Bohr effect, where hemoglobin's affinity for oxygen decreases, thus making this factor favorable for oxyhemoglobin formation.

4. **Lower Temperature**:
- Temperature also affects hemoglobin's affinity for oxygen. Lower temperatures increase the affinity of hemoglobin for oxygen, thus favoring the formation of oxyhemoglobin. Conversely, higher temperatures decrease this affinity.

**Conclusion**:
All four factors (I. high pO2, II. low pCO2, III. lesser H+ concentration, IV. lower temperature) are favorable for the formation of oxyhemoglobin.

**Final Answer**: D) All of the above factors are favorable for the formation of oxyhemoglobin.

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