HUMAN NUTRITION

Detailed explanation-1: -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: -Pepsin is an aspartic protease that acts in food digestion in the mammal stomach. An optimal pH of around 2 allows pepsin to operate in its natural acidic environment, while at neutral pH the protein is denatured.

Detailed explanation-3: -Pepsin enzyme is secreted by gastric glands of the stomach as inactive pepsinogen to protect the cells of these secretory glands from strong protein digesting action of the enzyme. The inactive form of the enzyme is activated by acidic pH of stomach lumen and the stomach wall is protected by mucus lining.

Detailed explanation-4: -The hydrochloric acid in the gastric juice breaks down the food and the digestive enzymes split up the proteins. The acidic gastric juice also kills bacteria. The mucus covers the stomach wall with a protective coating.