Question

Reduction in pH in blood will do which of the following:
A. Reduce the rate of heartbeat
B. Reduce the blood supply to the brain
C. Decrease the affinity of hemoglobin with oxygen
D. Release bicarbonate ions by the liver

Answer 1

Hint: The small variation in pH influences the structure of the hemoglobin molecule and this difference itself is responsible for bringing about a shift in the structure of the hemoglobin that is essential for its primary role in our body.

Complete answer:
> The effect of pH on the transport pathways occurring in the blood first needs to be understood to understand this. The pH balance in the blood is often referred to as its acid-base balance and there is an acceptable amount in the human body for acids and bases in our blood at which the body will usually conduct its functions. The human body retains this optimal pH with the help of organs like the lungs and kidneys.
> In our bodies, there are many biochemical processes that are susceptible to pH. The concentration of carbon dioxide primarily influences our blood's pH. As it reacts with water, carbonic acid is formed in the presence of the enzyme carbonic anhydrase.
> This carbonic acid ends up losing a hydrogen ion and become the carbonate ion as seen in the reaction below –
\[C{O{_2}}+{H{_2}}O \leftrightarrow {H{_2}}C{{O_3}} \leftrightarrow {{H}^{+}}+ HC{O_3}^{-}\]
> As the consequences of this bicarbonate ion, the pH of the blood decreases, and this decrease in pH causes such change in the structure of hemoglobin that promotes the dissociation. In this way, to fulfill their demands and perform functions, the surrounding tissues receive the required amount of oxygen.
> Thus, it is now clear that if the blood pH decreases, hemoglobin's affinity to oxygen is also decreased and its dissociation occurs.

Thus, the correct response is C-'decrease hemoglobin's affinity to oxygen.'

Note: The loss of hydrogen ions from particular amino acids occurs at key locations in the hemoglobin structure, as the pH value rises in the blood. As a result of this, there is a transition in the hemoglobin structure that increases its capacity to bind oxygen. But hemoglobin takes up hydrogen ions and its affinity for oxygen is decreased in the opposite case as pH decreases.