Submitted by: Submitted by kimgaloyo
Views: 212
Words: 1451
Pages: 6
Category: Science and Technology
Date Submitted: 08/03/2012 10:40 PM
Classification of Lipids
Lipids that are ester or amides of fatty acids:
Waxes – are carboxylic acid esters where both
R groups are long straight hydrocarbon chain.
Performs external protective functions.
Triacylglycerol – are carboxylic acid triesters of glycerols. They are a major source of
biochemical energy.
Glycerophopholipids - triesters of glycerols that contain charged phosphate diesters. They help to control the flow of molecules into and out of cells.
Sphingomyelins – amides derived from an
amino alcohol, also contain charged
phosphate diester groups. They are essential
to the structure of cell membranes.
Glycolipids – amides derived from
sphingosine, contain polar carbohydrate
groups. On the cell surface, they connect with
by intracellular messengers.
Lipids that are not esters or amides:
Steroids – They perform various functions such as hormones and contributes to the structure of cell membranes.
Eicosanoids – They are carboxylic acids that are a special type of intracellular chemical messengers.
24.3 Properties of Fats and Oils
Oils: A mixture of triglycerols that is liquid
because it contains a high proportions of
unsaturated fatty acids.
Fats: A mixture of triglycerols that is solid
because it contains a high proportions of
saturated fatty acids.
Properties of triglycerols in natural fats and
oils:
Nonpolar and hydrophobic
No ionic charges
Solid triglycerols (Fats) - high proportions of
saturated fatty acids.
Liquid triglycerols (Oils) - high proportions
of unsaturated fatty acids.
Chemical Reactions of Triglycerols
Hydrogenation: The carbon-carbon double bonds in unsaturated fatty acids can be hydrogenated by reacting with hydrogen to produce saturated fatty acids. For example, margarine is produced when two thirds of the double bonds present in vegetable oil is hydrogenated.
Hydrolysis of triglycerols: Triglycerols like any
other esters react with water to form their carboxylic acid and...