1. Lipids

2. Lipids are soluble in nonpolar organic compounds
They have a variety of structures and functions

3. Fatty Acids Are Carboxylic Acid with Hydrocarbon Chains

4. Polyunsaturated fatty acids have more than one
double bond
The double bonds in naturally occurring fatty acids
Have the cis configuration
Double bonds in naturally occurring unsaturated
Fatty acids are separated by one methylene group

5. The three OH groups of glycerol are esterified with fatty acids
Triacylglycerols
a triacylglycerol
a fat or an oil
glycerol
fatty acids
The three OH groups of glycerol are esterified
with fatty acids

6. Fats are triacylglycerols existing as solid or semisolid
state at room temperature

7. Oils are liquid triacylglycerols

8. Average composition of fatty acids %
Type
Fat, Oil
C14
C16
C18
Unsaturated
Animal Fats
Butter
8-15
25-29
9-12
44-58
Lard
1-2
25-30
6-12
56-68
Beef tallow
2-5
24-34
15-30
31-59
Vegetable Oils
Olive
0-1
5-15
1-4
80-94
Peanut -
7-12
2-6
82-91
Corn
7-11
3-4
83-89
Soybean
6-10
2-4
84-91
Marine Oils
Whale
5-10
10-20
65-83
Fish
6-8
10-25
1-3
64-83
C14 = myristic acid
Unsaturated:
Oleic (D1)
C16 = palmitic acid
Linoleic (D2)
C18 = stearic acid
Linolenic (D3)

9. Phosphoacylglycerols
They are the major components of cell membranes
The terminal OH group of glycerol is esterified with
phosphoric acid

10. The most common phosphoacylglycerols in
membranes have a second phosphate ester linkage
Phosphoacylglycerols are classified as phospholipids

11. Phosphoacylglycerols form membranes by arranging
themselves into a lipid bilayer
Saturated fatty acids decrease membrane fluidity because their hydrocarbon chains can pack closely together.
Unsaturated fatty acids have the opposite effect

12. Sphingolipids They contain sphingosine instead of glycerol
They are also found in membranes
They are the major lipid components in the myelin
sheaths of nerve fiber

13. Two of the Most Common Kinds of Sphingolipids

14. Prostaglandins Prostaglandins are synthesized from arachidonic acid
They are responsible for regulating a variety of
physiological responses
Name in the format PGX, with X designating the
functional groups of the five-membered ring
postaglandin
skeleton

15. Naming Prostaglandins
PGE2
PGE1
PGF2a

16. Terpenes Terpenes contain carbon atoms in multiples of five
They are made by joining together 5-carbon isoprene
units
Oxygen-containing terpenes are sometimes called
terpenoids

17. The Isoprene Rule

20. Squalene, a triterpene, is a precursor of steroid
molecules

21. Lycopene and b-carotene are tetraterpenes called
carotenoids

22. Terpene Biosynthesis
Formation of geranyl pyrophosphate

24. Steroids All steroids contain a tetracyclic ring system
Many hormones are steroids
Hormones are chemical messengers

25. Methyl groups at C-10 and C-13 are called angular
The B, C, and D rings are trans fused
Methyl groups at C-10 and C-13 are called angular
methyl groups

26. The A and B rings are also trans fused in most naturally
occurring steroids
Substituents on the same side of the steroid ring system
as the angular methyl groups are b-substituents
Those on the opposite side of the plane of the ring
system are a-substituents

27. Classification of Steroids
1. Sterols
2. Bile Acids
3. Hormones
Adrenocorticoid hormon
Sex hormones
4. Steroid Glycosides
5. Steroid Alkaloids
6. Miscellaneous Steroids
Toxines… etc…

28. Cholesterol Is a Steroid