NANP Board Practice Exam

Which of the following is NOT a function of Glucosaminoglycans (GAGs)?

1. Cell signaling

2. Collagen fibrogenesis

3. Gas exchange

4. Ion transport

The correct answer is: Gas exchange

Glucosaminoglycans (GAGs) are long chains of disaccharides that play several important roles in the body, particularly in connective tissues. They are known to contribute to various biological functions, including cell signaling, as they can bind to proteins and influence cellular processes. GAGs also assist in collagen fibrogenesis, which is vital for the formation of collagen in the extracellular matrix, providing structural support to tissues. Gas exchange, however, is not a function of GAGs. This process primarily occurs in the lungs and involves the exchange of oxygen and carbon dioxide between the air and blood, which is facilitated by the respiratory system and does not involve GAGs directly. Similarly, while ion transport is essential for cellular functions and is mediated by different mechanisms such as ion channels and transporters, it is not a specific role attributed to GAGs. Therefore, the identification of gas exchange as the answer reflects an understanding that while GAGs are crucial for many biological processes, they do not participate in the respiratory gas exchange mechanism.