Dietetic Technician Practice Test

Protein digestion begins in the:

1. jejunum

2. stomach

3. small intestines

4. brush border

The correct answer is: stomach

Protein digestion begins in the stomach due to the action of gastric enzymes and hydrochloric acid. When proteins enter the stomach, the acidic environment facilitates the unfolding of protein structures, a process known as denaturation. This allows the enzyme pepsin, which is secreted in the inactive form pepsinogen and activated by the acid, to start breaking down the protein into smaller peptides. The stomach is critical for initiating protein digestion, as it provides the necessary acidity and enzyme action to break down complex proteins. After the stomach, protein digestion continues in the small intestines, where pancreatic enzymes further process the peptides into amino acids and smaller peptides, ultimately allowing for absorption. However, the initiation of this process clearly takes place in the stomach, making it the point where protein digestion first begins.