Biology / Unit 12 Bio 2775 short lesson, about 20 seconds
Stomach: Acid Environment and Pepsin
Captions available
The idea
The stomach digests protein in a highly acidic environment, pH 1.5 to 2.5, where pepsin — activated from inactive pepsinogen by hydrochloric acid — cleaves proteins into peptides.
In practice
Parietal cells secrete the hydrogen and chloride ions that combine into the stomach's hydrochloric acid.
Where people slip
Pepsin is made inactive as pepsinogen specifically to protect the stomach's own lining from digesting itself.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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