Question

Which of the following is true of carbon dioxide exchange? Select one: a. Carbon dioxide is produced in the mitochondria and cytoplasm of every living cell during respiration b. Carbon dioxide diffuses from cells into the blood plasma before entering erythrocytes. c. Carbonic acid is able to ionize and release protons into its environment, which has an effect of raising the pH. d. Hemoglobin helps maintain a constant pH in the blood by binding with H* ions released from bicarbonate ions.

Answer 1

Answer:

d. Hemoglobin helps maintain a constant pH in the blood by binding with H⁺ions released from bicarbonate ions.

Explanation:

The presence (CO₂) in in the erythrocytes lowers its pH as a result the affinity of hemoglobin decreases for oxygen. The carbon dioxide (CO₂) reacts with water to form carbonic acid in the presence of the enzyme carbonic anhydrase which is present in the erythrocytes or red blood cells. The carbonic acid then changes into two ions hydrogen ion (H⁺) and bicarbonate ion (HCO₃⁻).  As a result of H⁺ ions, the pH of blood drops. Haemoglobin pick up hydrogen ions to balance the decrease in pH. Thus, haemoglobin helps in maintaining constant pH or keep pH of blood in buffer.