Explain the difference between mechanical and chemical digestion and provide an example.

Explain the difference between mechanical and chemical digestion and provide an example.

• A. Mechanical digestion is physical breakdown (chewing, peristalsis); chemical digestion is enzymatic breakdown (amylase on starch)
• B. Mechanical digestion occurs by bile salts; chemical by acid
• C. Mechanical digestion is enzymatic; chemical digestion is physical
• D. Mechanical digestion occurs only in mouth; chemical only in stomach

Answer: (C)

Mechanical digestion is the physical breakdown of food into smaller pieces, done by actions like chewing in the mouth and the stomach’s muscular churning and peristalsis. These processes don’t change the chemical nature of the molecules—they just make the food easier to handle and expose more surface area for later digestion. Chemical digestion, on the other hand, uses enzymes and acids to break chemical bonds, turning large molecules into smaller, absorbable units. A classic example is saliva’s amylase acting on starch in the mouth, starting the chemical breakdown of carbohydrates. Other examples include stomach acid and enzymes like pepsin breaking down proteins, and pancreatic enzymes finishing the job in the small intestine. So, the key difference is physical shattering versus chemical bond-breaking by enzymes. The statement that mechanical digestion is enzymatic and chemical digestion is physical isn’t correct because mechanical processes are physical, while chemical digestion relies on enzymes to hydrolyze macromolecules.

Mechanical digestion is the physical breakdown of food into smaller pieces, done by actions like chewing in the mouth and the stomach’s muscular churning and peristalsis. These processes don’t change the chemical nature of the molecules—they just make the food easier to handle and expose more surface area for later digestion.

Chemical digestion, on the other hand, uses enzymes and acids to break chemical bonds, turning large molecules into smaller, absorbable units. A classic example is saliva’s amylase acting on starch in the mouth, starting the chemical breakdown of carbohydrates. Other examples include stomach acid and enzymes like pepsin breaking down proteins, and pancreatic enzymes finishing the job in the small intestine.

So, the key difference is physical shattering versus chemical bond-breaking by enzymes. The statement that mechanical digestion is enzymatic and chemical digestion is physical isn’t correct because mechanical processes are physical, while chemical digestion relies on enzymes to hydrolyze macromolecules.