AP BIOLOGY

Detailed explanation-1: -Pepsin is a stomach enzyme that serves to digest proteins found in ingested food. Gastric chief cells secrete pepsin as an inactive zymogen called pepsinogen. Parietal cells within the stomach lining secrete hydrochloric acid that lowers the pH of the stomach. A low pH (1.5 to 2) activates pepsin.

Detailed explanation-2: -An enzyme made in the stomach that breaks down proteins in food during digestion. Stomach acid changes a protein called pepsinogen into pepsin.

Detailed explanation-3: -Of these five components, pepsin is the principal enzyme involved in protein digestion. It breaks down proteins into smaller peptides and amino acids that can be easily absorbed in the small intestine.

Detailed explanation-4: -Pepsin is secreted as inactive pepsinogen in the stomach, which is converted to active pepsin first by the acidity of the stomach and then by an autodigestive effect of pepsin itself.