In which part of the gastrointestinal (GI) tract are disaccharides hydrolyzed into monosaccharides by enzymes?

• A. Esophagus
• B. Small intestine
• C. Stomach
• D. Large intestine

Answer: (B)

Verified step by step guidance

1. Understand the process of carbohydrate digestion: Carbohydrates are broken down into simpler sugars (monosaccharides) for absorption. This involves enzymatic hydrolysis of disaccharides into monosaccharides.
2. Recall the role of disaccharidases: Enzymes like maltase, sucrase, and lactase are responsible for breaking down disaccharides (e.g., maltose, sucrose, lactose) into monosaccharides (e.g., glucose, fructose, galactose).
3. Identify the location of disaccharidase activity: These enzymes are located on the brush border of the small intestine, specifically on the microvilli of the intestinal epithelial cells.
4. Eliminate incorrect options: The esophagus and stomach are primarily involved in mechanical digestion and protein digestion, respectively, and do not produce disaccharidases. The large intestine is involved in water absorption and does not play a role in carbohydrate digestion.
5. Conclude that the small intestine is the correct answer: The small intestine is the site where disaccharides are hydrolyzed into monosaccharides by enzymes on the brush border.