[Campbell Biology P.956] According to Figure 41.10 and the accompanying text, what is the co... | Practice Question

According to Figure 41.10 and the accompanying text, what is the correct sequence of events for the activation of pepsin within the stomach lumen?

  • A: Chief cells release pepsinogen; HCl converts pepsinogen to pepsin; Pepsin then activates more pepsinogen.
  • B: Parietal cells release pepsinogen; Pepsin converts HCl to active pepsin; HCl then activates more pepsinogen.
  • C: HCl is released; Pepsinogen is released; Pepsin then activates HCl.
  • D: Pepsinogen and pepsin are simultaneously released; HCl then denatures them.

Explanation

Chief cells secrete pepsinogen, an inactive precursor. Hydrochloric acid HCl converts this inactive pepsinogen into active pepsin. Once active, pepsin can then activate more pepsinogen, creating a positive feedback loop and initiating further protein digestion.