AAMC FL Practice Exam 2025 - Free Practice Questions and Study Resources.

Hydrochloric acid plays a crucial role in the stomach by creating an acidic environment that is essential for protein denaturation and digestion. When food enters the stomach, the high acidity (pH of about 1.5 to 3.5) helps unfold proteins. This unfolding, or denaturation, increases the accessibility of the protein's peptide bonds, facilitating subsequent enzymatic action. The main digestive enzyme in the stomach, pepsin, is secreted in an inactive form known as pepsinogen. The low pH activates pepsinogen into pepsin, enabling it to cleave the peptide bonds in proteins, further contributing to their digestion into smaller peptides.

In contrast, while carbohydrates begin to be digested by salivary amylase in the mouth, hydrochloric acid does not play a significant role in their digestion in the stomach. Bile salts, produced in the liver and stored in the gallbladder, are primarily involved in fat emulsification and are released in the small intestine, not activated by gastric acid. Absorption of nutrients occurs mainly in the small intestine, not the stomach, where the environment is geared more towards digestion rather than absorption. Therefore, the correct option regarding the role of hydrochloric