Question

What are the two ways in which new bicarbonate ions are generated?

1) Through the reaction of carbon dioxide with water
2) Through the dissociation of carbonic acid

Answer 1

Bicarbonate ions are generated through the reaction of carbon dioxide with water to form carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. These biochemical reactions are facilitated by carbonic anhydrase and occur predominantly in erythrocytes, being essential for pH regulation in blood.

Step-by-step explanation:

Bicarbonate ions play a crucial role in maintaining the acid-base balance in the body and are generated primarily through reactions involving carbon dioxide (CO₂) and water. There are two main ways in which bicarbonate ions are formed:

1. The first method is the direct reaction of carbon dioxide with water to form carbonic acid (H₂CO₃), which is catalyzed by the enzyme carbonic anhydrase, primarily in erythrocytes (red blood cells). This reaction can be represented as:
2. CO₂ (dissolved) + H₂O → H₂CO₃
3. The produced carbonic acid then dissociates into bicarbonate ions (HCO₃⁻) and hydrogen ions (H+). This is the second way bicarbonate ions are formed and can be represented as:
4. H₂CO₃ → HCO₃⁻ + H+

These reactions are reversible, allowing bicarbonate ions to recombine with hydrogen ions to form carbonic acid, which subsequently converts back into carbon dioxide and water, particularly at the pulmonary capillaries during the process of exhalation.