1. Bioorganic
Lipids
12/5/2019
Dr Seemal Jelani Chem-160

2. Introduction
Structurally heterogeneous class of bioorganic compounds include diverse types of molecules as
Fats and oils
Waxes
Cholesterol and its derivatives
Some vitamins
Prostagladins
All of them have limited solubility in water
12/5/2019
Dr Seemal Jelani Chem-160

3. Lipids are esters of long chain fatty acids and alcohols.
Monomer : Fatty acids are lipids’ building blocks
Definition: It can be defined as nonpolar organic compound insoluble in polar solvent but soluble in organic solvents such as benzene ,ether, chloroform and boiling alcohol.
Biological role of lipids: Lipids are found naturally in all living organisms.
1) It represents in cell structure and has a structural function in the cell. It is present in cell membranes.
2) An essential source of energy in the body. It gives more energy than carbohydrate and proteins.

4. Characteristics of Lipids
Large class of water-insoluble bioorganic compounds
In humans and many animals excess carbohydrates and other energy-yielding foods are converted to, and stored in the body as lipids known as fats
This is a major way of storing chemical energy and carbon atoms in the body
12/5/2019
Dr Seemal Jelani Chem-160

5. Lipids function as covering for nerve fibres
Fats and other lipids surround and insulate vital body organs, providing protection from mechanical shock and helping to maintain correct body temperature
Lipids function as covering for nerve fibres
Basic structural components of all cell membranes
Many chemical messengers in the human body “ hormones” are lipids
12/5/2019
Dr Seemal Jelani Chem-160

6. Classification By structure: Simple: fats, oils, waxes, steroids.
Complex: phospholipids, spingolipids, glygolipids.
The derivatives: hormones, fat-solubility vitamins
On the basis of whether they undergo hydrolysis reactions in alkaline solution:
Saponifiable lipids can be hydrolyzed under alkaline conditions to yield salts of fatty acids.
Nonsaponifiable lipids do not undergo hydrolysis reactions in alkaline solution.
12/5/2019
Dr Seemal Jelani

7. Lipids Lipids at a Glance Glycerol esters Hydrolysis products
Saponifiable lipids
Can be hydrolysed under alkaline conditions
Nonsaponifiable Lipids
Glycerol esters
Hydrolysis products
Non Glycerol esters
Not a Hydrolysis products
12/5/2019
Dr Seemal Jelani Chem-160

8. Waxes Triacylglycerols Fats and Oils 12/5/2019
Dr Seemal Jelani Chem-160

9. Phosphoacylglycerols
Sphingolipids
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Dr Seemal Jelani Chem-160

10. Nonsaponifiable Lipids
Steroids
Fat Soluble vitamins
Eicosanoids
Terpenes
Pheromones
12/5/2019
Dr Seemal Jelani Chem-160

11. Structure and occurrence
Fatty acids are monocarboxylic acids that contain long, unbranched hydrocarbon chains generally 12 to 26 carbon atoms in length
They are rarely found free in nature but rather occurs mostly in esterified form in the structure of Saponifiable lipids
12/5/2019
Dr Seemal Jelani Chem-160

12. Fats can be divided according to their chemical composition to:
Simple lipids:
These compounds are: esters of fatty acids with glycerol.
The triacylglycerol (TAG) is the simplest and most common fat. It is the form in which lipids are stored in the cell.

13. Saturated fatty acid Hexadecanoic acid (Palmitic acid)
12/5/2019
Dr Seemal Jelani Chem-160

14. Alternative notations Condensed and Sawtooth
Condensed structure
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Dr Seemal Jelani Chem-160

15. Monounsaturated fatty acids
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Dr Seemal Jelani Chem-160

16. Trans
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Dr Seemal Jelani Chem-160

17. Saturated and unsaturated fatty acids
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Dr Seemal Jelani Chem-160

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Dr Seemal Jelani Chem-160

20. Polyunsaturated fatty acids Omega-3 and Omega-6 Fatty acids
Multiple double bonds
12/5/2019
Dr Seemal Jelani Chem-160

21. Omega-3 and Omega-6 Fatty acids important in human body chemistry
Classification
The basis for the omega classification system involves the following considerations
A fatty acid has two ends
Methyl (CH3) end
Carboxyl (COOH) end
12/5/2019
Dr Seemal Jelani Chem-160

22. O CH3-(CH2)4-(CH=CH-CH2)4-(CH2)2-C OH Methyl end Carboxyl end
12/5/2019
Dr Seemal Jelani Chem-160

23. This is the way by which tracking of fatty acids is done
In omega classification system, the carbon chain is numbered beginning at the methyl end, which is the reverse of the usual way.
This reverse numbering system is used because of the mechanism by which fatty acid carbon chains are lengthened during biotransformations within the body
Lengthening involves adding carbon atoms, two at a time at the carboxyl end of the chain
This is the way by which tracking of fatty acids is done
12/5/2019
Dr Seemal Jelani Chem-160

24. Omega-3 and Omega-6 Fatty acids
Polyunsaturated fatty acid with its endmost double bond three carbons away from its methyl end
Omega-6 Fatty acids
Polyunsaturated fatty acid with its endmost double bond six carbons away from its methyl end
12/5/2019
Dr Seemal Jelani Chem-160

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26. Lauric acid Palmitic acid Myristic acid Palmitoleic acid 12/5/2019
Dr Seemal Jelani Chem-160

27. Essential Fatty acids
Needed by the human body and must be obtained from dietary sources because they cannot be synthesized within the body from other substances
Essential fatty acids:
1 Linoleic acid
2 Linolenic acid
12/5/2019
Dr Seemal Jelani Chem-160

28. Linoleic acid and Linolenic acid
Both are 18-carbon polyunsaturated acids
Linoleic acid is an omega-6 acid
Linolenic acid is an omega-3 acid
12/5/2019
Dr Seemal Jelani Chem-160

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Dr Seemal Jelani Chem-160

30. Both contribute to proper membrane structure
Deficiency of Linoleic acid
Skin reddens and become irritated, infection and dehydration occur and liver may develop abnormalities and conditions will reverse on the restoration of the fatty acid
12/5/2019
Dr Seemal Jelani Chem-160

31. EPA (Eicosapentaenoic acid) DHA (Docosahexaenoic acid)
Both of these are starting points for the synthesis of a variety of other longer-chain polyunsaturated acids which are:
EPA (Eicosapentaenoic acid)
DHA (Docosahexaenoic acid)
Arachidonic acid major precursor of eicosanoids (substances that help regulate blood pressure)
12/5/2019
Dr Seemal Jelani Chem-160

32. EPA (Eicosapentaenoic acid) DHA (Docosahexaenoic acid)
Both of them are important constitutes of the communication membranes of the brain and its normal development, and also active in the retina of the eye
Sources:
Vegetable oils, meat and fish live in deep cold water are good source of linoleic acid and other omega-6 acids
12/5/2019
Dr Seemal Jelani Chem-160