What is a physiological role of bicarbonate ions in the body?

• A. They act as a primary energy source
• B. They regulate blood pH by neutralizing acids
• C. They enhance oxygen transport
• D. They promote digestive enzyme activity

Answer: (B)

Bicarbonate ions play a crucial physiological role in the regulation of blood pH. They are a key component of the bicarbonate buffer system, which helps maintain the blood's acidic or alkaline balance. By neutralizing excess acids in the blood, bicarbonate ions help prevent significant fluctuations in pH levels, ensuring that the body remains within a narrow pH range that is vital for normal cellular function.

When acids are produced in the body, whether through metabolic processes or the ingestion of acidic foods, bicarbonate ions can react with these acids to form carbonic acid, which can then be converted to carbon dioxide and water. This reaction effectively reduces acidity, thereby stabilizing pH levels. This buffering action is essential for maintaining homeostasis, particularly in the respiratory and renal systems, where bicarbonate can be regulated to meet the body’s changing acid-base needs.

The other options, while important bodily functions, do not relate directly to the role of bicarbonate ions. Energy source, oxygen transport, and digestive enzyme activity involve different biological systems and components, such as carbohydrates, hemoglobin, and various digestive enzymes, respectively.