OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What is the location where lipase functions to break down fats?

1. In the intestines

2. In the stomach

3. In the mouth

4. In the liver

The correct answer is: In the stomach

Lipase is an enzyme that specifically breaks down fats into fatty acids and glycerol. While lipase is indeed produced in several locations within the digestive system, its most active function occurs in the intestines where dietary fats are primarily digested. In the small intestine, bile salts emulsify fats, creating a larger surface area for lipase to perform its function efficiently. In the stomach, lipase does start the process of fat digestion, but its activity here is limited due to the acidic environment, and it is not the primary site for fat breakdown. The mouth does contain some lipase, particularly in infants, but it is not significant for adult digestion. The liver produces bile, which aids in fat digestion, but lipase itself is not produced there. Therefore, the intestines stand out as the primary location where lipase effectively breaks down fats, making that the appropriate choice.