Lipids are energy-rich organic compounds made up of carbon, hydrogen and oxygen. They contain less oxygen than carbohydrates. Some lipids also contain nitrogen and phosphorus. Lipids are non-polar and insoluble in water but soluble in non-polar solvents. Major types of lipids include fats, oils, waxes, phospholipids and steroids. Lipids function to store energy, form cell membranes, act as metabolic water sources, and reduce water evaporation. Fats and oils are triglycerides formed from glycerol and fatty acids bonding through esterification, removing three water molecules. Fats often contain saturated fatty acids while oils contain unsaturated fatty acids.

1. CHAPTER 4
CHEMICAL COMPOSITIONOF
THE CELL
4.4 LIPIDS

2.  Energy rich organic compounds made of :
1) carbon
2) hydrogen
3) oxygen
 The percentage of oxygen in lipids is lower
than in carbohydrate.
 Some lipids contain nitrogen and phosphorus.
 As lipids are non-polar molecules, they are
insoluble in water but dissolve readily in other
lipids and in non-polar solvents such as ether
and ethanol.

3.  Fats and oils (triglycerides)
 Waxes
 Phospholipids
 Steroids

4.  Store large amounts of energy for long
terms.
 Act as sources of energy.
 Form a major part of the structure of cell
membranes.
 Act as a metabolic source of water.
 Reduce the lost of water by evaporation.

5.  Fats are solid at room temperature while oils are
liquid.
 Fats and oils are triglycerides.
 Triglycerides is formed from a condensation
reaction between one molecules of glycerol and
three molecules of fatty acids. The bonds formed
are called ester bonds. Three molecules of
water are removed in this reaction.
 Fats often contain only saturated fatty acids
while oils usually contain unsaturated fatty acids.

6. Glycerol triglycerides
+ condensation +
3 molecules of 3 molecules of
Fatty acids hydrolysis water

7. GLYCEROL
Fatty acid fatty acid
+ condensation
Fatty acid GLYCEROL fatty acid
hydrolysis +
Fatty acid fatty acid 3H2O

8. COMPARING AND CONTRASTING SATURATED
FATS WITH UNSATURATED FATS
SIMILARITIES
 Both are triglycerides.
 They yield 38kJ per gram.
 Their molecules aggregate
into globules because of
their hydrophobic
properties.

9. DIFFERENCES
SATURATED TYPES OF FATS UNSATURATED
FATS FATS
absent PRESENCE OF DOUBLE BONDS presence
IN FATTY ACIDS
unable ABILITY TO REACT WITH able
ADDITIONAL HYDROGEN
ATOMS
Solid CONDITION AT ROOM Liquid
TEMPERATURE
higher MELTING POINT lower
likely CAUSE DISEASES OF THE unlikely
HEART AND ARTERIES
unlikely BECOME RANCID DUE TO likely
OXIDATION
Butter, animal EXAMPLES Olive oil, corn
fats oil

10. CREATE BY : ASMIDAR
MOHD JAMIL
FARY_LURVIST 101’