Which substance is secreted by chief cells in an inactive form?

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Multiple Choice

Which substance is secreted by chief cells in an inactive form?

Chief cells produce pepsinogen, an inactive enzyme precursor (a zymogen). This design keeps the protein-digesting activity from harming the cells that secrete it. In the stomach’s acidic environment, pepsinogen is activated by hydrochloric acid and converted into pepsin, the active protease that begins digesting dietary proteins. The activation can be amplified by pepsin itself in a positive feedback loop. The other substances aren’t inactive precursors from chief cells: mucin is secreted by mucus-secreting cells to protect the lining, hydrochloric acid is produced by parietal cells as active acid, and gastric lipase is secreted (and acts) as an active enzyme.

Chief cells produce pepsinogen, an inactive enzyme precursor (a zymogen). This design keeps the protein-digesting activity from harming the cells that secrete it. In the stomach’s acidic environment, pepsinogen is activated by hydrochloric acid and converted into pepsin, the active protease that begins digesting dietary proteins. The activation can be amplified by pepsin itself in a positive feedback loop. The other substances aren’t inactive precursors from chief cells: mucin is secreted by mucus-secreting cells to protect the lining, hydrochloric acid is produced by parietal cells as active acid, and gastric lipase is secreted (and acts) as an active enzyme.

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