What is the role of enzymes in digestion?

• A. They store energy for later use
• B. They transport nutrients to cells
• C. They help chemical reactions take place
• D. They regulate heartbeat

Answer: (C)

Enzymes act as biological catalysts, speeding up the chemical reactions that break down food in digestion. They enable large molecules to be split into smaller, absorbable units by catalyzing hydrolysis reactions. For example, starch is broken down by amylase, proteins by proteases, and fats by lipase. They are specific to their substrates and work best at particular pH and temperature conditions within the digestive tract, often produced in the mouth, stomach, and pancreas.

This catalytic role—making digestion occur efficiently at body conditions—is why this option is the best fit. They don’t store energy, transport nutrients, or regulate heartbeat, which are different functions.