Question

Dissociation of oxyhaemoglobin in blood increases when there is

• A. increase in pH and decrease in ${\mathrm{CO}}_2$ concentration
• B. decrease in temperature and increase in $O_2$ concentration
• C. increase in $O_2$ concentration and decrease in ${\mathrm{CO}}_2$ concentration
• D. decrease in pH and increase in ${\mathrm{CO}}_2$ concentration

Answer 1

The correct option is D decrease in pH and increase in ${\mathrm{CO}}_2$ concentration

$O_2$ can bind with haemoglobin in a reversible manner to form oxyhaemoglobin.
In the tissues, low ${\mathrm{pO}}_2$, high ${\mathrm{pCO}}_2$, high $H^{+}$ concentration (low pH) and higher temperature exist. These conditions are favourable for dissociation of oxygen from the oxyhaemoglobin.

In the alveoli, there is high ${\mathrm{pO}}_2$, low ${\mathrm{pCO}}_2$, lesser $H^{+}$ concentration (high pH) and lower temperature. These factors are all favourable for the formation of oxyhaemoglobin.