Which enzyme digests starch in saliva, and which enzyme digests protein in the stomach?

• A. Amylase digests protein; Pepsin digests starch
• B. Amylase digests starch; Pepsin digests protein
• C. Lactase digests starch; Lipase digests protein
• D. Protease digests starch; Amylase digests fat

Answer: (B)

Enzymes have specific targets and work in particular places in the digestive tract. In saliva, the enzyme that begins breaking down starch is amylase, which cleaves starch into smaller sugars such as maltose. In the stomach, the enzyme that digests proteins is pepsin, which cuts peptide bonds to form shorter peptides, and it is activated by the acidic gastric environment. The other options mix up substrates and locations: lactase targets lactose (a sugar), lipase targets fats, and protease is a general protein-digesting term that doesn’t describe starch digestion. Salivary amylase doesn’t function effectively in the stomach because the strong acid inactivates it, cementing the idea that starch digestion starts in the mouth and proceeds differently than protein digestion in the stomach.