The things we eat and drink must be broken down into smaller molecules before our cells can use them for energy, growth and healing. This process is called digestion. Digestion starts in our mouths when our teeth chew food into a soft pulp. This is called mechanical digestion because the food is physically broken down into smaller pieces, but its chemical composition remains the same. A bit of chemical digestion, or the breakdown of nutrients into smaller molecules by proteins called enzymes, also starts in the mouth. The chewed up food then moves through your esophagus into your stomach where more enzymes break it down further, and your body extracts nutrients from the food. What’s leftover after the digestion process moves into your small intestine, then your large intestine, and finally expelled as a waste material called feces.

Question

Which of the following is an example of chemical digestion?

A
A whole grape enters your mouth and your teeth break it up into smaller pieces that are easier to swallow.

B
The bagel you ate this morning eventually leaves your body as a waste material called feces.

C
Your body uses the eggs you had for breakfast for energy, growth and healing.

D
Little pieces of chewed up hamburger are broken down into smaller molecules by enzymes.

Answer 1

D. Little pieces of chewed up hamburger are broken down into smaller molecules by enzymes.

This is an example of chemical digestion, as it involves the breakdown of food into smaller molecules by enzymes, which changes the chemical structure of the food.