NEETZoologyBreathing and Exchange of Gases
What is a sigmoid curve in relation to hemoglobin?
Options
- AA plot of saturation of hemoglobin with CO₂ against pCO₂
- BA plot of saturation of hemoglobin with O₂ against pO₂
- CA plot of saturation of hemoglobin with H⁺ concentration against pO₂
- DA plot of saturation of hemoglobin with temperature against pO₂
Correct answer
B. A plot of saturation of hemoglobin with O₂ against pO₂
Step-by-step solution
Hemoglobin is a red coloured iron containing pigment present in the RBCs. O2 can bind with hemoglobin in a reversible manner to form oxyhaemoglobin. Each haemoglobin molecule can carry a maximum of four molecules of O2. Binding of oxygen with haemoglobin is primarily related to partial pressure of O2. Partial pressure of CO2, hydrogen ion concentration and temperature are the other factors which can interfere with this binding . A sigmoid curve is obtained when percentage saturation of haemoglobin with O2 is plotte