Lipids Flashcards
A heterogeneous class of naturally occurring organic compounds classified
together on the basis of common solubility properties.
Lipids
Substances made up of different compositions and structures.
Lipids
Insoluble in water, but soluble in organic (nonpolar) solvents including diethyl
ether, dichloromethane, and acetone.
Lipids
Compounds with a waxy, greasy or oily characteristic, commonly found in
plants
and animals.
lipids are Insoluble in water, but soluble in organic (nonpolar) solvents including ______
diethyl
ether, dichloromethane, and acetone.
Energy-storage lipids
triacylglycerols
Membrane lipids
- phospholipids, sphingoglycolipids, and cholesterol
Emulsification lipids
- bile acids
Chemical messenger lipids
steroid hormones and eicosanoids
Protective-coating lipids
biological waxes
- Lipids exhibit structural diversity.
- Some are ___ some are ____and some are _____
and some are
esters,, amides, alcohols (acyclic and cyclic), polycyclic.
CLASSIFICATION OF LIPIDS
Two Main Classes:
Saponifiable lipids
Nonsaponifiable lipids
can undergo saponification reaction, a process of
hydrolyzing esters under basic conditions.
Saponifiable lipids
these are esters and thus all
belong to the first class.
Triglycerides, waxes, phospholipids, and sphingolipids
this is also Further classified as simple and complex lipids, based on the number of
components in their structure.
Saponifiable lipids –
Simple lipids are made up of____while complex lipids
are made of ________
fatty acids and an alcohol
fatty acids, an alcohol, plus other components.
are not esters and cannot be hydrolyzed.
* Steroids and prostaglandins belong to this class.
Nonsaponifiable lipids
simple lipids:
waxes, triglycerides
complex lipids
phosphoglycerides, spingolipids
nmonsaponifiable lipids
steroids, prostaglandins
Lipids fundamental building blocks.
FATTY ACIDS
When in aqueous solution, ions of fatty acids
associate with one another to form a spherical
clusters, called
micelles.
Nonpolar chains are held together by ___
weak
dispersion forces.
Large micelles contains large number of ____
fatty acid
molecules.
___are important in a
number of biological functions, such as the
transport of insoluble lipids in the blood.
Micelle formation and structure
COMMON CHARACTERISTICS OF FATTY ACIDS FOUND IN
NATURAL LIPIDS
- Straight-chains carboxylic acids (unbranched).
- Most common fatty acids has size ranging from 10 to 20 carbons.
- Even number of carbon atoms.
NATURAL LIPIDS Two types:
Saturated
* Unsaturated
all C-C bonds are single bonds, no double bonds
Saturated
contains one or more double bonds
Unsaturated
one C=C bond
Monounsaturated
2 or more C=C bonds present - up to six double bonds
are present in fatty acids
Polyunsaturated
Two shorthand notations used for representing fatty acids:
Delta notation (Δ)
Omega notation (ω) (unsaturated)
counting of C starts from the carboxyl end
Delta notation (Δ) -
– reference is the methyl end carbon,
which is the opposite of delta carbon; also known as the nutritional notation.
Omega notation (ω) (unsaturated) –
Ω-3 family
– linolenic acids
Ω-6 family
linoleic and arachidonic acids
Ω-9 family
oleic acid
creates a long
characteristic bend, or kink in the
fatty acid chain that is not found in
saturated fatty acids.
Cis configuration
Most of unsaturated fatty acids exist in nature usually contain ___ in the
cis configuration.
double bonds
The longer the C chain the ___
the melting point
higher
Three essential fatty acids:
Linoleic acid (an omega-6 fatty acid)
* Linolenic acid (an omega-3 fatty acid)
* Arachidonic acid
Prevents cardiovascular
diseases, heart diseases
- Linoleic acid (an omega-6 fatty acid)
- Linolenic acid (an omega-3 fatty acid)
are both used to produce hormone-like substances that
regulate a wide range of functions and characteristics such as inflammation
response to injury and infection, blood pressure, blood clotting, blood lipid levels
and immune response.
Linoleic and linolenic acids
is not found in plants, but can be synthesized by mammals only
from linoleic acid.
Arachidonic acid
A triester of glycerol with three fatty acids.
Triglyceride
In triglycerides, all three _____ of glycerol are esterified with fatty acids.
hydroxyl groups
In triglycerides, The reaction process involved is called
esterification
Fats and oils that are produced naturally are
mixtures of triglycerides
if the three –OH groups of the glycerol are esterified to the
same fatty acids such as trispalmitin, triolein.
Simple TAGs
different fatty acids are esterified to the –OH groups of glycerol.
Mixed TAGs
Triglycerides rich in unsaturated fatty acids are generally liquid at room
temperature and are called oils.
(Low melting points)
Triglycerides rich in unsaturated fatty acids
Plant sources such as corn oil, sunflower oil
Triglycerides rich in saturated fatty acids are generally semisolids or solids
at room temperature and are called fats.
(High melting points)
hydrolyzes fats and oils by treating with water and an acid catalyst to
yield glycerol and fatty acids. The reverse process of ester formation.
* The most important reactions of fats and oils.
Hydrolysis
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