Anatomy and Physiology II Practice Test

Which enzyme is produced in an inactive form in the stomach and digests protein?

1. Pepsin

2. Amylase

3. Trypsin

4. Cholecystokinin

The correct answer is: Pepsin

Pepsin is the enzyme produced in the stomach and is secreted in an inactive form known as pepsinogen. When pepsinogen is released into the acidic environment of the stomach, it undergoes a biochemical transformation and becomes active pepsin. This active form of pepsin is responsible for digesting proteins by breaking them down into smaller peptides. This process is crucial for protein digestion, as it initiates the breakdown of food proteins into peptides that can be further digested in the small intestine. The acid in the stomach not only activates pepsin from pepsinogen but also helps create an optimal pH environment for the enzyme’s function. The other choices listed represent different enzymes or hormones that perform distinct roles. Amylase, for instance, is primarily involved in the digestion of carbohydrates and is not produced in the stomach. Trypsin, on the other hand, is produced by the pancreas, also in an inactive form called trypsinogen, and does its work in the small intestine. Cholecystokinin is a hormone that aids in digestion by stimulating the gallbladder to release bile but is not an enzyme responsible for protein digestion.