BN
CHAPTER 5
LIPID CHEMISTRY
1) DEFINITION AND CLASSIFICATION OF LIPIDS
2) FUNCTIONS OF LIPIDS
3) DEFINITION AND CLASSIFICATION OF FATTY ACIDS
4) NOMENCLATURE OF FATTY ACIDS
5) PUFAs
6) GLYCEROL
7) CHOLESTEROL
8) TRIGLYCERIDES
9) IDENTIFICATION OF FATS AND OILS / LIPID INDICES
10) PHOSPHOLIPIDS
11) GLYCOLIPIDS
12) AMPHIPATHIC LIPIDS
13) LIPOSOMES
14) PROSTAGLANDINS
15) PROSTACYCLINS AND THROMBOXANES
16) LEUKOTRIENES
, LIPID CHEMISTRY
DEFINITION OF LIPIDS
Lipids are organic substances, relatively insoluble in water, soluble in
organic solvents (alcohol, ether), related to fatty acids and utilized by living
cells
CLASSIFICATION OF LIPIDS
Lipids are classified into the following groups
SIMPLE LIPIDS
These are esters of fatty acids with alcohol.
They are of two types:
1. Fats and oils (triacylglycerol)
These are esters of fatty acids with glycerol.
The difference between fat and oil is only physical.
Thus, oil is a liquid while fat is a solid at room
temperature
2. Waxes
These are esters of fatty acids with alcohol other than
glycerol.
Cetyl alcohol is most commonly found in waxes
,COMPLEX OR COMPOUND LIPIDS
These are esters of fatty acids with alcohols containing additional groups
such as phosphate, nitrogenous base, carbohydrate and protein.
They are further divided as
PHOSPHOLIPIDS
These are lipids containing fatty acid, alcohol, phosphoric acid and
nitrogenous base.
They are of the following types:
1. Glycero-phospholipids –
They contain glycerol as the alcohol e.g.
a) Phosphatidyl choline (lecithin)
b) Phosphatidyl ethanolamine (cephalin)
2. Sphingo-phospholipid
They contain sphingol as the alcohol. e.g.
Sphingomyelin
3. Phosphoinositide
They contain inositol as the alcohol. e.g.
Phosphatidyl inositol
, GLYCOLIPIDS
These are lipids containing fatty acid, sphingol, nitrogenous base and
carbohydrate e.g.
1. Cerebroside
2. Ganglioside
LIPOPROTEIN
They are a combination of lipids and proteins e.g.
1. Chylomicron
2. VLDL
3. LDL
4. HDL
DERIVED LIPIDS
These are the derivatives obtained by the hydrolysis of simple and
compound lipids. e.g.
1. Glycerol
2. Fatty acid
3. Fat soluble vitamins
4. Steroid hormones
5. Hydrocarbons
6. Ketone bodies
CHAPTER 5
LIPID CHEMISTRY
1) DEFINITION AND CLASSIFICATION OF LIPIDS
2) FUNCTIONS OF LIPIDS
3) DEFINITION AND CLASSIFICATION OF FATTY ACIDS
4) NOMENCLATURE OF FATTY ACIDS
5) PUFAs
6) GLYCEROL
7) CHOLESTEROL
8) TRIGLYCERIDES
9) IDENTIFICATION OF FATS AND OILS / LIPID INDICES
10) PHOSPHOLIPIDS
11) GLYCOLIPIDS
12) AMPHIPATHIC LIPIDS
13) LIPOSOMES
14) PROSTAGLANDINS
15) PROSTACYCLINS AND THROMBOXANES
16) LEUKOTRIENES
, LIPID CHEMISTRY
DEFINITION OF LIPIDS
Lipids are organic substances, relatively insoluble in water, soluble in
organic solvents (alcohol, ether), related to fatty acids and utilized by living
cells
CLASSIFICATION OF LIPIDS
Lipids are classified into the following groups
SIMPLE LIPIDS
These are esters of fatty acids with alcohol.
They are of two types:
1. Fats and oils (triacylglycerol)
These are esters of fatty acids with glycerol.
The difference between fat and oil is only physical.
Thus, oil is a liquid while fat is a solid at room
temperature
2. Waxes
These are esters of fatty acids with alcohol other than
glycerol.
Cetyl alcohol is most commonly found in waxes
,COMPLEX OR COMPOUND LIPIDS
These are esters of fatty acids with alcohols containing additional groups
such as phosphate, nitrogenous base, carbohydrate and protein.
They are further divided as
PHOSPHOLIPIDS
These are lipids containing fatty acid, alcohol, phosphoric acid and
nitrogenous base.
They are of the following types:
1. Glycero-phospholipids –
They contain glycerol as the alcohol e.g.
a) Phosphatidyl choline (lecithin)
b) Phosphatidyl ethanolamine (cephalin)
2. Sphingo-phospholipid
They contain sphingol as the alcohol. e.g.
Sphingomyelin
3. Phosphoinositide
They contain inositol as the alcohol. e.g.
Phosphatidyl inositol
, GLYCOLIPIDS
These are lipids containing fatty acid, sphingol, nitrogenous base and
carbohydrate e.g.
1. Cerebroside
2. Ganglioside
LIPOPROTEIN
They are a combination of lipids and proteins e.g.
1. Chylomicron
2. VLDL
3. LDL
4. HDL
DERIVED LIPIDS
These are the derivatives obtained by the hydrolysis of simple and
compound lipids. e.g.
1. Glycerol
2. Fatty acid
3. Fat soluble vitamins
4. Steroid hormones
5. Hydrocarbons
6. Ketone bodies
