In which human digestive organ do proteases (e.g., pepsin) primarily function to begin protein digestion?

• A. Esophagus
• B. Stomach
• C. Large intestine (colon)
• D. Oral cavity (mouth)

Answer: (B)

Verified step by step guidance

1. Understand that proteases are enzymes that break down proteins into smaller peptides or amino acids.
2. Recall that pepsin is a specific protease that is active in an acidic environment.
3. Identify the organ in the digestive system where the environment is acidic enough for pepsin to function effectively; this is the stomach.
4. Recognize that the esophagus, large intestine, and oral cavity do not provide the acidic conditions necessary for pepsin activity.
5. Conclude that proteases like pepsin primarily begin protein digestion in the stomach.