The precursor to pepsin found in the gastric cells is known as?

Pepsinogen is the precursor to pepsin and is produced by the gastric cells, specifically the chief cells in the stomach lining. This inactive form, or zymogen, is crucial for protecting the tissues of the stomach from the damaging effects of digestive enzymes, as pepsin itself is active and capable of breaking down proteins. Once pepsinogen is secreted into the gastric lumen, it is activated by hydrochloric acid (HCl) in the stomach to become pepsin.

The other options listed are also zymogens, but they serve different roles in digestion. Procarboxypeptidase, chymotrypsinogen, and trypsinogen are precursors to other digestive enzymes that operate in the small intestine rather than the stomach. Procarboxypeptidase is converted to carboxypeptidase, chymotrypsinogen is activated to chymotrypsin, and trypsinogen is turned into trypsin, all of which play essential roles in further protein digestion after the initial breakdown in the stomach. However, in the context of gastric cells specifically, pepsinogen is the relevant precursor to pepsin.