Digestion

Question 1

Why are lipids hard to digest?

Answer 1

Lipids (fats and oils) are triglycerides — made of glycerol + 3 fatty acids
They’re hydrophobic, so they clump together in large globules that enzymes can’t easily access

Question 2

What do bile salts do?

Answer 2

• They emulsify large lipid droplets into smaller droplets.
• This massively increases the surface area for enzymes to work on.
• Bile salts = Blender -> They chop up fats to help enzymes get in.

Question 3

What is the role of micelles?

Answer 3

It hydrolyses triglycerides into:
Monoglycerides (glycerol + 1 fatty acid)
Free fatty acids

Question 4

What are micelles?

Answer 4

• After digestion, the monoglycerides + fatty acids stay associated with bile salts, forming micelles.
• Allows the fatty acids and monoglycerides to diffuse directly through the phospholipid bilayer of the epithelial cell (because they’re lipid-soluble).