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Experiment 7:
Properties of lipids:
Introduction:
Objective:
1) To determine some of the physical and chemical properties of
lipid.
2) To identify the products of hydrolysis.
Theory:
The group of biologically active substances called lipid
includes compounds
of widely different compositions and structures. They include
true fats and
fat-like substances. On the basis of their chemical nature, they
may be
classified in to three group:
1) simple lipids considered as the true fats,
2)compound lipids which contain parts of other biochemical
compounds in
addition to the glycerol and fatty acid components, and
3) miscellaneous lipids which are the fat like substsnces.
True fats or neutral fats are esters of the trihydroxy alcohol,
glycerol,and
high molecular weight acids of the continuous chain type . they
are
designated as triglycerides or glyceryl esters. Exampeles of
compound
lipids are: those with phosphoric acid called phosphatides,
those with
nitrogenious bases as well as phosphoric acid called
phospholipids, those
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with carbohydrates called glycolipids, and those with proteins
called
lipoproteins. The miscellaneous lipids are those which do not
have the fatty
acid radical but have the same solubility properties as the
fats. Classified
among them are the sterols.cartenoids, fat soluble vitamins.
EXPERIMENTAL
F. Salkowskis Test for Cholesterol
1-Where was the chloroform layer formed?
It the bithm of test tube
3- describe the result?
Some sample change the color to dark violet
4-record results in the table.
Fat sample Color with sulfuric
acid
Test result
interpretation
1-buttercolestrol Dark violet It contain cholestrol
2-lardinolin Dark violet It contain cholestrol3-margarine oleic
acid Dark violet It contain cholestrol
4.corn oil olive oil trunsparent It doesnt contain
cholestrol
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5-
describe the result. Nothing happen
was cholesterol present in any of the samples? Yes in the
sample
1,2, and 3
which fat sample gave a positive result? Sample 1,2,3 and
negative result ? olive oil
