Where does digestion begin for proteins and which pancreatic enzymes continue it?

Where does digestion begin for proteins and which pancreatic enzymes continue it?

• A. Digestion begins in the mouth with amylase and continues with pancreatic amylase.
• B. Digestion begins in the stomach with pepsin, and continues in the small intestine with pancreatic proteases trypsin, chymotrypsin, and carboxypeptidases.
• C. Digestion begins in the stomach with lipase, and continues in the small intestine with pancreatic lipases.
• D. Digestion begins in the colon with pancreatic proteases.

Answer: (B)

Protein digestion starts in the stomach, where acid denatures proteins and pepsin begins cutting peptide bonds to produce smaller peptides. As the chyme moves into the small intestine, pancreatic proteases take over: trypsin and chymotrypsin cleave internal peptide bonds, while carboxypeptidases trim amino acids from the ends of the chains. These pancreatic enzymes are released as inactive zymogens and are activated in the intestinal lumen to prevent damage to the tissues. This pathway explains why protein digestion begins in the stomach and continues in the small intestine with pancreatic proteases. Other options miss this sequence: the mouth mainly digests starch with salivary amylase, fats are acted on by pancreatic lipase, and the colon is not where this primary proteolytic digestion occurs.

Protein digestion starts in the stomach, where acid denatures proteins and pepsin begins cutting peptide bonds to produce smaller peptides. As the chyme moves into the small intestine, pancreatic proteases take over: trypsin and chymotrypsin cleave internal peptide bonds, while carboxypeptidases trim amino acids from the ends of the chains. These pancreatic enzymes are released as inactive zymogens and are activated in the intestinal lumen to prevent damage to the tissues. This pathway explains why protein digestion begins in the stomach and continues in the small intestine with pancreatic proteases. Other options miss this sequence: the mouth mainly digests starch with salivary amylase, fats are acted on by pancreatic lipase, and the colon is not where this primary proteolytic digestion occurs.