lipids biochemistry , types of lipids .pdf

lipids biochemistry.pdf

1. Dr. Ekram Desouky

2. Definition Classification
Biological
importance

3. Lipids are organic compounds formed mainly from alcohol and
fatty acids combined together by ester linkage

4. In the human body, these molecules can be synthesized in
the liver
Generally found in the oil, butter, whole milk, cheese, fried
foods, and also in some red meats.

5. Organic substances relatively insoluble in
water but soluble in organic solvents like
ether, chloroform, benzene and acetone
Definition

6. Storage form of energy
Structural component
of cell membrane and
nervous system. It is
mainly phospholipids
in nature that are not
affected by starvation.
Supply the body with
fat-soluble vitamins (A,
D, E and K).
Protection of internal
organs against external
temperature.
Cholesterol enters in
membrane structure
and is used for
synthesis of adrenal
cortical hormones,
vitamin D3 and bile
acids.

7. Classification
•Lipids are classified as
– Simple,
–Complex,
–Derived and Lipid- associating substances.

8. A- Simple Lipids (Fats & Waxes)
•They are esters of FA with various alcohols

9. Fats or oils
Alcohol is
GLYCEROL
Waxes
Alcohol is other
than glycerol

10. Esters of fatty acids with
glycerol.
also called triglycerides.
esters of glycerol+ 3 FA
Oils are fats in the liquid
state.

11. NEUTRAL FATS
Neutral fats are also called as triacylglycerols (TAG) or
triglycerides (TG). These are esters of the trihydric alcohol,
glycerol with fatty acids.

13. Subclassified according to the type of prosthetic group
Phospholipids Glycolipids Lipoproteins
Compound or conjugated
Lipids

14. FA + ALCOHOL + PHOSPHORIC ACID

15. FA + ALCOHOL + CARBOHYDRATE

16. Examples of lipoproteins:
Chylomicrons
Very low density lipoprotein
(VLDL)
Low density lipoprotein (LDL)
High density lipoprotein (HDL)
Lipid with
prosthetic group
PROTEIN

17. Example
Fatty acids
Steroids
Ex:
Cholesterol
Vitamin A
and D

18. Fatty acids are
long-chain carboxylic acids. R (CH
2)
n-COOH
typically 12-18 carbon atoms.
insoluble in water.
saturated or unsaturated.

19. saturated with all single C–C bonds.





unsaturated with one or more double C=C bonds.
•They contain no double bonds with 2-24 or more carbons.
•They are solid at room temperature.
•They may be even or odd numbered
•are liquids at room temperature
monounsaturated
they contain one double bonds
polyunsaturated
they contain more than one double bond.

Fatty acids

21. Saturated Fatty Acids
Depending on length of hydrocarbon chain
a. Short chain : Less than 10 carbon atoms

b. Long chain : more than carbon atoms

23. Unsaturated Fatty Acids

Unsaturated Fatty Acids
• Contain one or more double C=C bonds
• Nonlinear chains do not allow molecules
to pack closely
• Few interactions between chains
• Low melting points
• Liquids at room temperature

24. Unsaturated fatty acids may be subclassified
Into:
 Mono-unsaturated: having single double bond
 Polyunsaturated: with 2 or more double bonds

25. Mono-unsaturated fatty acid structure

Delta end

27. Mono-unsaturated
ω9 family—Oleic acid

Non essential fatty acids

28. polyunsaturated fatty acids
•They are called essential fatty acids, because they
cannot be synthesized by the body and have to be
supplied in the diet.
•Unsaturated fatty acids are also designated
 ω3 (omega 3) family—Linolenic acids
ω6 family—Linoleic and Arachidonic acids
Linoleic and Linolenic acids are essential fatty acids.
•Arachidonic acid can be synthesized in the body, if the
essential fatty acids are supplied in the diet.

29. Poly-unsaturated fatty acid structure
Delta end

31. Clinical Significance of polyunsaturated
fatty acids
Formation of healthy cell membranes
Proper development and functioning of the
brain and nervous system
Enter in composition of phospholipid (a type of
compound lipid)
Causing esterification of cholestrol (free
cholestrol), so decrease atheroscelrosis(CHD).