2. Lipids
• The word lipid is derived from a Greek word
“lipos” which means Fat.
• A lipid is a macrobiomolecule that is soluble
in non polar solvents.
• Non-polar solvents are
typically hydrocarbons used to dissolve.
• Do not (or do not easily) dissolve in water.
3. Functions
• The functions of lipids include storing energy, signaling, and acting
as structural components of cell membranes.
• Lipids have applications in the cosmetic and food industries as well
as in nanotechnology.
• They serve as a storage form of metabolic fuel.
• they serve as a transport form of metabolic fuel.
• They provide the structural components of membranes
(phospholipids, glycolipids, galactolipids, sphingolipids)
• They have protective functions in bacteria, plants, insects, and
vertebrates, serving as a part of the outer coating between the
body of the organism and the environment.
4. Classifications
• Four types
1. Simple : Fatty acids and Alcohols
2. Compound (complex): Fatty acids, Alcohols &
other groups.
3. Derived: derived from simple and complex both.
4. Miscellaneous: possesses characteristics of
lipids.
5. Lipids
Simple lipids
These are esters
of Fatty acids
with various
alcohols.
Complex lipids
These are Esters
of fatty acids
containing groups
e.g. Phosphate,
nitrogen,
carbohydrates,
sulphur etc.
+
+
Derived lipids
These are
derived from
simple or
complex lipids.
It contains a
hydrocarbon
ring along with
long fatty acid
chain side chain.
+
Miscellaneous lipids
These are the lipids
having
characteristics
of lipids .
Carotenoids
Squalene
Terpenes
Pentacepore
Fatty acids
Alcohols
Fatty acids
Alcohols
Other Groups
Hydro carbon
Hydro carbon
6. Simple lipids
1.Triacylglycerol (triglyceride)
Most abundant lipid in animals.
Composed of fatty acids and glycerol.
Storage form of lipids.
Source of energy.
2. Waxes
Composed of fatty acids and glycerol.
7. Fatty Acids
It is Simplest form of lipids
It Usually contains an even number of carbon atoms
(14C-20C)
Biosynthesis of fatty acid occurs with sequential
addition of 2 carbon atom.
Chain may be saturated (containing no double bonds)
or unsaturated (containing one or more double bonds)
It is found in esterified form.
Fats of animal origin are more simple than that of plant
origin.
Examples are Palmitic acid and stearic acid
8. Essential fatty acids
The fatty acid cant be synthesized by the body and
therefore has to be supplied in the diet.
FUNCTIONS
Membrane structures and functions
Transport of cholesterol
Formation of lipoprotein
Prevention of fatty liver
Disorder due to Deficiency
Phrynoderma,toad skin
9. Compound lipids
1. Phospholipids
It Contains fatty acid, alcohols, Nitrogen base
phosphoric acid. Examples Lecithin, Cephalin etc
Phospholids are of 2 types:
a. Glycerophospholipids: contains glycerol as
alcohol.
b. Sphingophospholipids: contain sphingosine as
alcohol.
11. Functions of Phospholipids
Phospholipids provide barriers in cellular
membranes to protect the cell,
they make barriers for the organelles within those
cells.
Phospholipids work to provide pathways for various
substances across membranes.
SPHINGOPHOSPHOLIPIDS
Found in large quantities in brain and nerve Tissue.
The combination of sphingosine plus fatty acid is
known as ceramide – found in glycosphingolipids
12. Derived/precursor lipids
These are derived from simple or complex lipids.
It contains a hydrocarbon ring along with long fatty
acid chain side chain.
It Includes
Fatty acid,
Glycerol,
mono acyl glycerol
Steroids,
Cholesterol,
Ketone body,
Vit A,D, E, K
13. Steroids
• Steroids compound containing cyclic steroid nucleus.
• Several steroids in biological systems.
– Cholestrol
– Bile acids
– Vitamin D
– Sex Hormone
– Adrenocortical hormones
– Cardiac glycosides
– Alkaloids
14. Derived/precursor lipids
CHOLESTEROL
It is a precursor of a large number of equally important
steroids
Bile acids,
Adrenocortical hormones,
Sex hormones,
D vitamins – Ergosterol
Cardiac glycosides
Function
Present in nervous tissues – insulating cover
Biochemical function – precursor for many biochemical
substances and component of cell membrane.
15. Bile acids
• It synthesized from cholesterol in the liver.
• Bile acids keep bile cholesterol in a soluble state
asmicelles to promote the digestion of lipids in the
intestine.
Primary bile acids : Cholic acid and chenodeoxycholic
acid
Secondary bile acids : lithocholic acid and deoxycholic
acid.
16. Miscellaneous lipids
These are the lipids having characteristics of lipids but having
different characteristic group.
Carotenoids
Squalene
Terpenes
Pentacepore
17. Saturated Fats
• Saturated fats have no double bonds in their chemical
structure.
• They are “saturated” with hydrogen atoms.
• Because of their chemical structure, they have a solid
consistency at room temperature.
• Saturated fats can be found in a variety of foods, including:
Animal meat including beef, poultry, pork.
Certain plant oils such as palm kernel or coconut oil.
Dairy products including cheese, butter, and milk.
18. Unsaturated Fats
• Unsaturated fats are typically liquid at room
temperature.
• They differ from saturated fats in that their chemical
structure contains one or more double bonds.
• They can be further categorized as:
Monounsaturated Fats: It contains only one double bond
in its structure and liquid at room temperature. e.g. canola
oil and olive oil.
Polyunsaturated Fats: It contains two or more double
bonds in their structure and liquid at room temperature.
e.g. safflower oil, sunflower oil, and corn oil.