Lipids are insoluble in water but soluble in nonpolar solvents. They serve important structural and energy storage functions in biological systems. Lipids can be classified as fatty acids, waxes, triglycerides, phosphoglycerides, sphingolipids, glycolipids, and steroids. Fatty acids are the building blocks of more complex lipids and some must be obtained through diet. Triglycerides are the main form of lipid energy storage. Phosphoglycerides are important components of cell membranes. Cholesterol is an essential steroid lipid that is a precursor for other steroids and bile acids.

1. LIPIDS
KRITIKA CHANDEL

2. WHAT ARE LIPIDS?
• Lipids are insoluble in water but soluble in non polar
solvents.
• Lipids can be dispersed uniformly in water in the form of
minute droplets.
• Lipids are the actual or potential esters of higher fatty
acids.
• Lipids are highly energetic.

3. FUNCTIONS
• Structural components of biological membranes.
• Energy reserves mainly in the form of triacyl-glycerols.
• Serve as vitamins and hormones or their precursors.
• Thermal insulators.
• Wax coating that protects plants.

4. CLASSIFICATION OF LIPIDS

5. FATTY ACIDS
• Fatty acids are long chain aliphatic carboxylic acids.
• Fatty acids in natural fats contain an even number of
carbon atoms.
• The carbon chains may be saturated (all single bonds) or
unsaturated (containing double bonds)
• The double bonds are usually in cis configurations.

6. ESSENTIAL FATTY ACIDS
• Linoleic acid, linolenic acid and arachidonic acid, these
cannot be synthesized in the body and must be obtained
from the diet. These are essential fatty acids.

7. WAXES
• Waxes are esters of fatty acids and long chain or higher
monohydroxy alcohols.
Examples:-
• LANOLIN
• SPERMACETI
• WAX-D
• BEEWAX

8. TRIGLYCERIDES
• These are commonly called simple fats or oils.
• These are particularly present in the adipose tissue of the
body.
• These are the esters of fatty acids and glycerol.

9. HYDROLYSIS OF TRIGLYCERIDES

10. SAPONIFICATION OF TRIGLYCERIDES

11. SOAPS
Each soap molecule has a long hydrocarbon chain,
sometimes called its 'tail', with a carboxylate 'head'. In
water, the sodium or potassium ions float free, leaving a
negatively-charged head.

12. HYDROGENATION OF TRIGLYCERIDES

13. PHOSPHOGLYCERIDES
• These are also called phospholipids.
• These in addition to fatty acid and glycerol, also contain a
phosphate.
• These are the main constituents of the cell membrane
lipids and are also found in brain and cardiac tissues.

14. LECITHINS:-These phospholipids are obtained when a
nitrogenous base choline gets attached to the -OH
group of phosphate of phosphatidic acid.
CEPHALINS:-Phosphoglycerides that contains the amino
alcohols ethanolamine or serine are called cephalins.

15. SPHINGOLIPIDS
• Sphingolipids are complex lipids that contain sphingosine
instead of glycerol.
• One important type of sphingolipids are the
sphingomyelins.

16. GLYCOLIPIDS
• Glycolipids are sphingolipids that contain carbohydrates
(usually monosaccharide).
• They are also referred to as cerebrosides because of their
abundance in brain tissue.
• These are present mainly in the outer part of the cell
membranes.

17. STEROIDS
• Steroids are classified as lipids because they are soluble in
nonpolar solvents, but they are nonsaponifiable.
• The basic steroid structure contains four fused rings.
CHOLESTEROL:-
• It is an essential component of cell membranes, and is a
precursor for other steroids.
• There is apparently a correlation between high levels of
cholesterol in the blood and atherosclerosis.
BILE ACIDS:-
• Bile is a yellowish brown or green fluid produced in the liver.
• Bile salts act like soaps and other emulsifiers.

18. PROSTAGLANDINS
• Prostaglandins are cyclic compounds synthesized from
arachidonic acid.
• Like hormones, they are involved in a host of body
processes, including reproduction, blood clotting,
inflammation, and fever.

19. THANK YOU