Where and how does carbohydrate digestion begin?

Where and how does carbohydrate digestion begin?

• A. In the mouth, the salivary gland releases alpha amylase that initiates hydrolysis of carbohydrate when food enters the mouth.
• B. In the stomach, gastric acid initiates digestion of carbohydrates.
• C. In the small intestine, pancreatic amylase initiates digestion.
• D. In the mouth, lingual lipase initiates carbohydrate digestion.

Answer: (A)

Carbohydrate digestion begins in the mouth with salivary alpha-amylase (ptialin) released by the salivary glands. This enzyme starts breaking down starch by cleaving alpha-1,4 glycosidic bonds, producing smaller sugars like maltose and dextrins as you chew. The stomach’s acidic environment inactivates this enzyme, so most carbohydrate digestion continues in the small intestine, where pancreatic amylase resumes breakdown and brush-border enzymes finish converting to monosaccharides for absorption. The other statements don’t fit because gastric acid doesn’t initiate carbohydrate digestion, pancreatic amylase acts after chewing and in the small intestine, and lingual lipase digests fats, not carbohydrates.

Carbohydrate digestion begins in the mouth with salivary alpha-amylase (ptialin) released by the salivary glands. This enzyme starts breaking down starch by cleaving alpha-1,4 glycosidic bonds, producing smaller sugars like maltose and dextrins as you chew. The stomach’s acidic environment inactivates this enzyme, so most carbohydrate digestion continues in the small intestine, where pancreatic amylase resumes breakdown and brush-border enzymes finish converting to monosaccharides for absorption. The other statements don’t fit because gastric acid doesn’t initiate carbohydrate digestion, pancreatic amylase acts after chewing and in the small intestine, and lingual lipase digests fats, not carbohydrates.