Final answer:
HCl functions to denature proteins and create an acidic environment for enzymatic activity, while the stomach enzyme pepsin breaks down proteins into amino acids.
Step-by-step explanation:
The functions of hydrochloric acid (HCl) in the stomach include aiding in the denaturation of food proteins, which unfolds proteins for more efficient enzymatic action, and providing the acidic environment necessary for certain stomach enzymes, like pepsin, to function effectively. HCl also helps kill pathogens present in food, contributing to the safety of the digestive process.
Pepsin is a stomach enzyme whose function is to catalyze the hydrolysis of peptide linkages within protein molecules, thus initiating their breakdown into individual amino acids which are essential for various bodily functions.