Question

What would happen if blood is acidic?
A) Binding of oxygen and haemoglobin increases.
B) Red blood corpuscles are formed in higher numbers.
C) Binding of oxygen with haemoglobin decreases.
D) There is no change in oxygen binding nor number of red blood cells.

Answer 1

The blood becomes acidic due to increase in concentration of carbon dioxide in it. This is caused due to imbalance in homeostasis.

Complete Answer:
The homeostatic regulation of the pH of the body's extracellular fluid (ECF) is known as acid-base homeostasis. Its balance is very important for the normal physiological functioning of the body. Various extracellular proteins such as the proteins of plasma and membrane are very sensitive to the extracellular pH. An increase in blood carbon dioxide concentration leads to a decrease in blood pH causing it to be acidic. The acidification results in release of oxygen from haemoglobin proteins. This causes decreased affinity of haemoglobin molecules towards oxygen.
In order to maintain the pH within very narrow limits, the body has developed various mechanisms. The enzymes and ion channels can lose their function if proteins involved get denatured. An increase in blood carbon dioxide concentration leads to a decrease in blood pH causing it to be acidic. The acidification results in release of oxygen from haemoglobin proteins. This causes decreased affinity of haemoglobin molecules towards oxygen.
The imbalance can be balanced by chemical buffers which are called the first line of action for maintaining acid base homeostasis. The bicarbonate buffer system is an example of a buffer system used in maintaining acid-base homeostasis. Other examples are the phosphate buffer system, and the protein buffer system.
The carbonic acid concentration in the ECF is the second line of defence for regulation of acid-base homeostasis. Changes in the rate and depth of controls the homeostasis by blowing off or retaining carbon dioxide which is present as carbonic acid in the blood plasma.
The renal system is the third defence system, which removes or adds bicarbonate ions from or to the ECF. The bicarbonate is enzymatically converted to carbonic acid in the renal tubular cells, it is derived from metabolic carbon dioxide which. The carbonic acid spontaneously dissociates into hydrogen ions and bicarbonate ions.

Thus, the correct answer is- C. Binding of oxygen with haemoglobin decreases.

Note: In contrast to decreased affinity of haemoglobin for oxygen in acidic pH, increase in pH can be observed due to decrease in carbon dioxide concentration in ECF. This results in increased affinity of haemoglobin towards oxygen.