Question

Increase in the body temperature makes oxygen haemoglobin curve to shift
A. Right
B. Left
C. Central
D. None of these

Answer 1

Hint: The significance of oxygen haemoglobin curve is we can know the amount of oxygen carried and released by the haemoglobin. In other words, we can say that this curve relates the oxygen saturation and partial pressure of the oxygen in the blood. This helps in the finding out the affinity of the haemoglobin towards oxygen.

Complete Answer:
The oxygen-haemoglobin dissociation curve is the curve or graph between the amount of haemoglobin in its saturated form on the Y-axis and on X-axis amount of oxygen tension.
This graph has a sigmoidal shape and there are some factors that affect this curve.
- pH: When there is a decrease in the pH, the amount of H+ increases and amino acid that is histidine at position 146, gets stabilized and removes the oxygen molecule from the haemoglobin. Thus, the graph shifts to the right. And when pH increases, the graph shifts to left.
- Carbon dioxide: Amount of the carbon dioxide affects the pH of the blood and which can shift the graph. Now, if the amounts of the carbon dioxide are high then it forms bicarbonates and other compounds which decreases the pH and ultimately leads to the shift to right. And in case of low amounts of carbon dioxide, pH increases and the graph shifts to left.
- Temperature: Whenever we increase the temperature, keeping the amount of oxygen the same, then the bond formation decreases and weakens the bond between the haemoglobin molecule and oxygen and bonds break thus, the graph shifts to the right. And when temperature decreases, the graph shifts to the left.

Thus, we can conclude that option ‘A’ is correct. Graph will shift to the right when temperature will increase.

Note: In humans, haemoglobin is the protein molecule which is responsible for the transportation of the oxygen from the lungs to all other parts of the body. Oxygen molecule binds to the iron atom of the heme prosthetic group.