During digestion, hydrochloric acid (HCl) lowers the stomach's pH and this causes the enzyme pepsinogen to be converted to its active form, called pepsin. Pepsin is a proteolytic enzyme, which means it cleaves (breaks) peptide bonds assocciated with food particles. The enzyme pepsin can also cleave pepsinogen into pepsin, and this causes the rate at which pepsinogen is converted to pepsin to increase. This is an example of:.
A) A negative feedback loop
B) A positive feedback loop
C) The importance of keeping your stomach pH high during digestion
D) The importance of hormones in activating pepsin

B) A positive feedback loop

Explanation:

In a feedback loop, when an action continues to occur due to the end product of an action, then, a positive feedback loop has taken place. The main action is triggered or enhanced by a positive feedback loop.

It is mainly stopped by a negative feedback loop.

In this case, since hydrochloric acid (HCl) lowers the stomach's pH during digestion and this causes the enzyme pepsinogen to be converted to pepsin and the enzyme pepsin can also cleave pepsinogen into pepsin, then this causes the rate at which pepsinogen is converted to pepsin to increase, it can be said that a positive feedback loop has taken place. It is a positive feedback loop because it enhances the action (when pepsinogen is converted to pepsin).

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