Laboratory: Lipids Flashcards
a vast group of biochemical molecules, and are among one of the most abundant biomolecule that is to be found in an organism, alongside carbohydrates and proteins.
Lipids
It is a class of compound that can be distinguished as hydrophobic molecules by its insolubility in water and solubility in nonpolar solvents such as chloroform or methanol.
Lipids
Building block of lipids
Fatty acids
are esters of long chain fatty acids and alcohols.
Lipids
defined as NON-POLAR organic compound insoluble in POLAR solvent, but SOLUBLE IN ORGANIC SOLVENTS
Lipids
An essential source of energy, reservoir for energy
Lipids
Esters of fatty acids with glycerol.
SIMPLE LIPIDS
is the simplest and most common fat. It is the form in which lipids are stored in the cell. Also known as neutral fat
triacylglycerol (TAG)
It contains glycerol, fatty acid, Nitrogenous base and Phosphoric acid.
COMPOUND LIPIDS (Conjugated lipids)
They are substances that are soluble in lipid or derived from above groups of lipids by hydrolysis
Derived lipids
SAPONIFIABLE VS NON-SAPONIFIABLE LIPIDS:
Easily hydrolyzed by NaOH and those generally have ester linkages.
Saponifiable Lipids
SAPONIFIABLE VS NON-SAPONIFIABLE LIPIDS:
Cannot be hydrolyzed by NaOH because they have no ester bonds
Non-saponifiable lipids
SAPONIFIABLE VS NON-SAPONIFIABLE LIPIDS:
Fats and oils
Saponifiable Lipids
SAPONIFIABLE VS NON-SAPONIFIABLE LIPIDS:
Cholesterol & Eicosanoids
Non-saponifiable lipids
TAG can be hydrolyzed into its component fatty acids and alcohol. This reaction can also be carried out in the laboratory by a process called _______ where the hydrolysis is carried out in the presence of a strong base (such as NaOH or KOH).
saponification
is a process of hydrolysis of oils or fat with alkaline and result in glycerol and salts of fatty acids (soap)
Saponification
It’s objective is to investigate the effect of NaCl on soap solubility
Separation of Soap by salting out
Principle: To get the soap out of solution by salting out, when added solid sodium chloride to the solution until saturation; separated soap in the form of insoluble and floats above the surface
Separation of Soap by salting out
The NaCl solution provides Na+ and Cl ions that bind to the polar water molecules, and help separate the water from the soap. This process is called _______ the soap
salting out
This test’s objective is to determine the iodine value of fats and oils and thus estimate the unsaturation of the fats and oils.
Test for Unsaturation
This test is specific for the double bonds in the lipid’s chain
Test for unsaturation of lipids
Pig’s brain contains a high amount of lipid content, the docosahexanoic acid (DHA) or popularly known as ______________
omega-3 fatty acid
This test’s objective is to isolate Non-Saponifiable and Saponifiable Lipids from Fish/Pig’s Brain
BRAIN LIPIDS
Reactions of the standards in different tests:
Lecithin in Kraut’s Test:
Orange ppt., dark red solution in the bottom
Reactions of the standards in different tests:
Cerebroside in Molisch Test:
Very light violet solution
Reactions of the standards in different tests:
Cholesterol in Liebermann-Burchard Test:
Emerald green solution
Reactions of the standards in different tests:
Cholesterol in Salkowski Test:
3 layers (colors)
- red solution
- turbid yellow solution
- clear yellow solution
General Tests for Lipids:
A yellow to brick-red colour is formed indicating the presence of cholesterol. There may be a red color in the upper layer (chloroform) and green fluorescence in the lower layer due to the heavier sulfuric acid settling.
SALKOWSKI’S TES
General Tests for Lipids:
Presence of a double bond in one cholesterol rings is responsible for its ability to form color products in the presence of Sulfuric acid
SALKOWSKI’S TEST
General Tests for Lipids:
Results in dehydration of cholesterol molecule with a formation of a red bicholestadien disulphonate.
SALKOWSKI’S TEST
General Tests for Lipids:
used to identify the presence of the double bond in one cholesterol ring. These rings are the ones that are responsible in the formation of color products in the presence of inorganic acids. The cholesterol is reacted with concentrated sulfuric acid that dehydrates to form the red part in the results
SALKOWSKI’S TEST
General Tests for Lipids:
It is used to detect the presence of steroids.
Liebermann-Burchard test
General Tests for Lipids:
In this test, the acetic anhydride reacts with the third carbon of the hydroxyl group of cholesterol and the steroid is the presence of strong acids that forms the blue-green color of the solution. This test should be done without any single amount of water for it will be contaminated.
Liebermann-Burchard test
LIBERMANN- BURCHARD TEST uses ______ and _____ as reagents, gives a characteristic green color in the presence of cholesterol. This color is due to the OH group of cholesterol and the unsaturation found in the adjacent fused ring.
acetic anhydride and sulfuric acid
General Tests for Lipids:
A positive reaction is indicated by appearance of a purple ring at the interface between the acid and test layers.
MOLISCH TEST
General Tests for Lipids:
Test mainly used for choline due to complexation
KRAUT’S TEST
General Tests for Lipids:
is a specific test for Choline (Lecithin) such as glycerophosphatides, sphingolipids and phosphorylated lipids
KRAUT’S TEST
General Tests for Lipids:
Test mainly used for cephalins, lecithins, and sphingomyelins
NINHYDRIN TEST
General Tests for Lipids:
Blue- violet solution indicates a positive result
NINHYDRIN TEST
______ gives a negative acrolein test
Cholesterol
Appearance of Isolated Complex Lipid Samples:
Cholesterol
Clear colorless solution
Appearance of Isolated Complex Lipid Samples:
Glycerophosphatides
Brownish yellow solution
Appearance of Isolated Complex Lipid Samples:
Sphingosine Phosphatides and Sphingosine Glycosides
Slightly turbid with suspended precipitate
