Summary
Chemical digestion is the breakdown of large, insoluble molecules into small, soluble molecules that can be absorbed by the body.
- Amylase — an enzyme that breaks down starch into maltose. Example: Amylase is secreted in the mouth and acts on starch.
- Protease — an enzyme that breaks down proteins into amino acids. Example: Pepsin is a protease that works in the stomach, while trypsin works in the small intestine.
- Lipase — an enzyme that breaks down fats into fatty acids and glycerol. Example: Lipase acts in the small intestine.
- Bile — an alkaline liquid that neutralizes stomach acid and emulsifies fats. Example: Bile is produced in the liver and stored in the gallbladder.
- Hydrochloric Acid — provides an acidic environment in the stomach for enzyme activity. Example: It helps pepsin function and kills harmful microorganisms.
Exam Tips
Key Definitions to Remember
- Chemical digestion: Breakdown of large insoluble molecules into small soluble molecules.
- Emulsification: Process of breaking down fats into smaller droplets.
Common Confusions
- Confusing mechanical digestion with chemical digestion.
- Misunderstanding the role of bile as an enzyme.
Typical Exam Questions
- What is the role of amylase in digestion? Amylase breaks down starch into maltose.
- How does bile aid in digestion? Bile neutralizes stomach acid and emulsifies fats.
- Where does protein digestion begin? Protein digestion begins in the stomach with pepsin.
What Examiners Usually Test
- Understanding of enzyme functions and locations.
- The role of bile and hydrochloric acid in digestion.