Submitted by: Submitted by Lizzy1
Views: 104
Words: 954
Pages: 4
Category: Science and Technology
Date Submitted: 02/06/2014 09:40 AM
Background: Lipids are a heterogeneous group of compounds synthesized by organisms that are
present in all biological tissues. These compounds are characterized as being sparingly soluble in
water, but highly soluble in nonpolar solvents (e.g., chloroform, ether, hexane, etc.). We can use
this solubility difference to extract and separate lipid constituents from the many polar
compounds that are contained in biological tissues. Lipids can be classified by a number of
schemes, but looking at them according to their biological function is most useful. Triglycerides
(or triacylglycerols) are fats and oils that serve as storage and transport forms of metabolic
energy. These compounds contain fatty acids (generally 3 molecules of saturated and unsaturated
in various combinations) that are esterified to a 3-carbon glycerol molecule. Waxes (long chain
fatty acids esterified to a long chain alcohol), hydrocarbons (long chain alkanes) and fatty
alcohols form protective surfaces on many plant and animal tissues. Lipids that are membrane
components are usually amphipathic and complex (phospholipids, sphingolipids, glycolipids).
Finally, there are a large group of low molecular weight, non-polar compounds that are not
derived from fatty acids (e.g., steroids, vitamins, carotenoids, quinones, etc.) and function as
hormones, vitamins, photopigments and other specialized roles. In the first part of the
experiment, you will obtain a crude lipid fraction from either plant and/or animal tissues. You
will analyze the lipids contained in your extracts using two dimensional (2-D) thin layer
chromatography (TLC) and measure the cholesterol content by spectrophotometry.
Metodes:
In eksperiment een word die Na2S2O3-oplossing gestandardiseer om die konsentrasie daarvan te bepaal. Voeg eerstens 10 mL 10% KI-oplossing in twee afsonderlike 250 mL Erlenmeyerflesse. Voeg 40 mL gedistilleerde water en 10 mL 50% H2SO4 by elke fles. Pipetteer presies 10.00 mL KMnO4-oplossing...