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: -Listen to pronunciation. (PEP-sin) 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: -Once a protein source reaches your stomach, hydrochloric acid and enzymes called proteases break it down into smaller chains of amino acids. Amino acids are joined together by peptides, which are broken by proteases.

Detailed explanation-4: -In the presence of acid, both forms of pepsinogen are converted to pepsin by removal of a short amino-terminal peptide. Pepsin is an endopeptidase that preferentially hydrolyzes peptide linkages where one of the amino acids is aromatic and accounts for approximately 20% of the protein digestion in the GI tract.

Detailed explanation-5: -Protease breaks down protein into amino acids.