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LIPIDS
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LIPIDS
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Lipids
are naturally accruing organic compounds which are soluble in BLOOR'S
REAGENT.
Bloor's reagent is a mixture of diethyl ether and ethyl alcohol. Generally lipids are fats and fat like compounds and they contain mostly carbon , hydrogen and oxygen. |
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TYPES
OF LIPIDS
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| There are three classes of lipids: | |||
| 1.
Simple lipids 2. Compound lipids 3. Steroids |
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SIMPLE
LIPIDS
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| Naturally occurring oils, fats and waxes are collectively known as " simple lipids". Simple lipids are the esters of long chain fatty acids with alcohols. | |||
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FATS
AND OILS
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| Natural fats and oils are the Esters of glycerol with long chain carboxylic acid (12 to 20 carbon atoms).These are known as triglycerides or triacylglycerols. | |||
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DIFFERENCE
BETWEENFATS AND OILS
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| Both
fats and oil are belong to the class of esters known as glycerides or triglycerides
but main difference between them is that oils are liquid at room temperature
(20OC) while fats are solids or semi solids
at room temperature. Oils contain higher proportion of glycerides
of unsaturated fatty acids while fats contain high proportion
of saturated. Examples of oils: oleic acid, linolenic acid, linoleic acid Examples of fats: Palmitic acid, staeric acid |
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| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | |||
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DRYING OIL
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| Drying
oils are those that contains large no of glycerides of unsaturated fatty
acids as Linoleic acid and lanolenic acid. Drying oils when exposed to air , they undergo oxidation and double bonds open up forming peroxides which then polymerize to from a dry, hard and tough film. |
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NON
DRYING OIL:
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| Non drying oils contain negligible amount of glycerides of unsaturated fatty acids | |||
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RANCIDIFICATION
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| When oils and fats are exposed to warm and moist air for a long time they give off offensive odor and become off-tastes. This process is called Rancidification. Rancidification caused by the hydrolysis of ester linkage or oxidation at double bond forming volatile aldehydes or bad smell. | |||
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WAXES
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| Naturally occurring esters of long-chain carboxylic acids with long- chain alcohols are called wax. Waxes are low melting point solids with waxy feeling. | |||
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TRUE
WAX
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| True
waxes are simple lipids Example: |
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| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | |||
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NON
TRUE WAX
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| Non true waxes are the esters of cholesterol, vitamin A & D | |||
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COMPOUND
LIPIDS
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| These
are the esters of glycerol with two saturated or unsaturated fatty acids
and some other compound such as carbohydrate, amino acid or amine
derivative, phosphoric acid or protein etc. They are also known as
complex or conjugated lipids. Example: lecithin, cephalins, sphingomelins etc. |
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STEROIDS
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Steroids are non-saponfiable lipids that contain polycyclic structures
in their molecule. Steroids can not be hydrolysed by strong base. Some of the common steroids are: Cholesterol, cholic acid, progesterone, |
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1.
CHOLESTEROL
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| It is the most common steroid found virtually in animal tissues, in blood, in brain and in spinal column. Cholesterol is a yellowish wax like substance closely related to fats. It deposits in arteries to elevate blood pressure causing heart attack. | |||
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2.
COLIC ACID
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| It is a derivative of cholesterol. Its sodium salt is found in bile. It is an enzymes , it breaks down fats into fatty acids. | |||
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3.
PROGESTERONE
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| This steroid controls the sexual development and functioning of body | |||
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FATTY
ACIDS
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Fatty acids are naturally occurring long chained saturated or unsaturated
carboxylic acid with 12 to 20 carbon atoms. They are obtained by the
hydrolysis of fats and oils. Example: Palmitic acid, Stearic acid, linoleic acid etc. |
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ESSENTIAL
FATTY ACIDS
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Fatty
acids which are unsaturated containing carbon-carbon double bond and cannot
be synthesized in animal body are known as essential fatty acids.
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FUNCTION
OF ESSENTIAL FATTY ACIDS
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They prevent deposition of cholesterol in arteries and veins. They
help in reproduction function and blood clotting. Their
deficiency results loss of weight in children . Their
deficiency results in the development of eczema. |
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| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | |||