Question

Oxyhaemoglobin is converted into hemoglobin during the internal respiration because
A. An enzyme splits oxyhemoglobin
B. Oxygen tension in tissues is less than capillary blood reaching tissues
C. CO tension is low in the blood that reaches tissues
D. Oxyhaemoglobin is unstable

Answer 1

Hint: Hemoglobin is the substance present in the red blood cells, and it is made up of two parts such as heme and globin, and the function of hemoglobin is to carry the oxygen to from the lungs to different parts of the body and also to carry the deoxygenated blood to lungs to gets oxygenated.

Complete answer:
Each hemoglobin contains 4 irons molecules which means that each hemoglobin can carry 4 oxygen molecules.
During internal respiration, an exchange of gases takes place between the body tissues and capillary blood.
Normally partial pressure of oxygen is more in the blood, that coming from the lungs, where here the blood is 100% saturated with oxygen.
When coming to the tissues, various metabolic activities are generally taken part in the tissues, and most of the oxygen, at least 25% of oxygen is utilized and so that in tissues, the partial pressure of oxygen falls, and the CO$_2$ is increased.
So the O$_2$ tension is more in capillary blood when compared to the O$_2$ tension in tissues.
As we know that gases are always diffused from high tension lower ones so that oxygen is dissociated with hemoglobin and diffuses to tissues.

So the correct option is B.

Note: The partial pressure of oxygen is more in capillary blood that is 100mm of Hg, and the partial pressure of oxygen in tissues is 40mm of Hg, so this is the reason where the oxygen is diffused from the capillary blood to tissues, by dissociating with hemoglobin present in capillary blood.