Bile: Function (Edexcel IGCSE Biology: Double Science)
Revision Note
Author
LáraExpertise
Biology Lead
The Role of Bile
- Bile has two main roles:
- Neutralising the hydrochloric acid from the stomach
- The alkaline properties of bile allow for this to occur
- This neutralisation is essential as enzymes in the small intestine have a higher (more alkaline) optimum pH than those in the stomach
- Breaking apart large drops of fat into smaller ones (and so increasing their surface area)
- This is known as emulsification
- Neutralising the hydrochloric acid from the stomach
- The more alkaline conditions and larger surface area allows lipase to chemically break down the fat (lipids) molecules into glycerol and fatty acids at a faster rate
Bile salts break large lipid droplets into smaller ones with a larger surface area
Exam Tip
Emulsification is the equivalent of tearing a large piece of paper into smaller pieces of paper.This is an example of mechanical digestion, not chemical digestion – breaking something into smaller pieces does not break bonds or change the chemical structure of the molecules which make it up, which is the definition of chemical digestion.
You've read 0 of your 0 free revision notes
Get unlimited access
to absolutely everything:
- Downloadable PDFs
- Unlimited Revision Notes
- Topic Questions
- Past Papers
- Model Answers
- Videos (Maths and Science)
Did this page help you?