LIPID MICELLE FORMATION Amphipathic lipids Examples Structure Micelles Micelle formation Conditions influence micelle formation Importance of micelles

1. z
Lipid micelle
formation

2. z
Amphipathic lipids
 Lipids are insoluble in water, that is hydrophobic
in nature due to the presence of hydrocarbon
groups.
 However, some of the lipids possess polar or
hydrophilic groups which tend to be soluble in
water.
 Molecules which contain both hydrophobic and
hydrophilic groups are known as amphipathic.

3. z
Examples of amphipathic lipids
 Among the lipids, fatty acids, phospholipids,
sphingolipids, bile salts and cholesterol (to some extent)
are amphipathic in nature.

4. z
Fatty acids contain a hydrocarbon chain with a
carboxyl group. The carboxyl group is polar in
nature with affinity to water (hydrophilic) while the
hydrocarbon chain of fatty acid is hydrophobic.

5. z
Phospholipids have a hydrophilic head (phosphate
group attached to choline, ethanolamine, inositol etc.)
and long hydrophobic tail.

6. z
Structure of amphipathic lipid
The general structure of an amphipathic lipid may be
represented as a polar or hydrophilic head with a non-polar
or hydrophobic tail

7. z
Micelles
 Micelles are the amphipathic lipid molecules that arrange
themselves in a spherical form in aqueous solutions.

8. z
Micelle formation
 When amphipathic lipids are
mixed in water (aqueous phase),
the polar groups (heads) Orient
themselves towards aqueous
phase while the non-polar groups
(tails) Orient towards the
opposite directions. This leads to
the formation of micelles.

9. z
Conditions influence micelle formation
 Kraft temperature
It is the minimum temperature above which the formation of
micelles takes place.
 Critical micelle concentration (CMC)
It is the concentration of surfactants above which micelles
formation takes place

10. z Importance of micelles
 Micelles act as emulsifiers that allows a compound that is usually insoluble in water to dissolve.
 They help the small intestine to absorb essential lipids and vitamins from the liver and gall
bladder.
 They carry complex lipids such as lecithin and lipid soluble vitamins (A, D, E and K) to the
small intestine.
 Micelles help clean the skin. Many facial washes use micelles to perform this task. They clean
the skin by removing oil and other substances without the need of being washed afterward.
 Micelles can increase reaction yield, create conditions more favorable to specific reaction
products (e.g. Hydrophobic molecules), and reduce required solvents, side products, and
required conditions.
 Micelle formation may also inhibit chemical reactions, such as when reacting molecules form
micelles that shield a molecular component vulnerable to oxidation.