BIOL10004 Chapter Notes - Chapter 2: Hydrophile, Amphiphile, Micelle
29 Jun 2018
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Biological Membranes
Structure and function of lipids (fats, oils, waxes)
Lipids:
oDiverse group of biomolecules
oFats, oils, waxes, phospholipids, steroids, carotenoid pigments
oDefined as substances extracted from biological materials using non-polar organic
solvents (benzene, hexane)
oComposed of Carbon, Hydrogen, Oxygen
Differs from carbohydrates (lower oxygen concentration)
oMay contain phosphorus and nitrogen
oPerform biologically important functions
Due to hydrophobic structures
Structural components of cell membranes
Transport and storage of energy, insulation
Forms protective and water-repellant coatings
Hormones, chemical messengers within and between cells
Mammals get lipids from diet, plants synthesis their own
Simple lipids:
oMost abundant lipids
oFormed by joining alcohol to fatty acid with hydrocarbon chain through ester linkage
oC-C single bond = saturated fatty acids
oC=C double bonds = unsaturated fatty acids
oOne double bone = monounsaturated fatty acid
oTwo or more double bond = polyunsaturated fatty acid
oDouble bond is in cis configuration = causes kink in structure of chain
oUnsaturated fatty acids do not pack as close together as saturated ones
oLess energy needed to break forces
oLower MP
Waxes
oEster which both alcohol and fatty acid have long hydrocarbon chains
oInsoluble in water due to non-polar nature of hydrocarbon chains
Triacyclglycerols
oNeutral fats or oils
oSimple lipids formed by esterification of three hydroxyl groups on three-carbon
alcohol, glycerol, with fatty acids
oForms triacylglycerol
oStored in special storage cells of adipose tissue
oEnergy content of fats = 37.67 kj / gram
o16.74 kj / gram in carbohydrates and proteins
oMore efficient way of storing energy and carbon reserves
Structure and function of phospholipids
Complex Lipids
oComplex lipids are components of membranes
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Document Summary
Structure and function of lipids (fats, oils, waxes) Lipids: diverse group of biomolecules o. Fats, oils, waxes, phospholipids, steroids, carotenoid pigments: defined as substances extracted from biological materials using non-polar organic solvents (benzene, hexane) o. Differs from carbohydrates (lower oxygen concentration: may contain phosphorus and nitrogen o. Mammals get lipids from diet, plants synthesis their own. Simple lipids: most abundant lipids o o o. Formed by joining alcohol to fatty acid with hydrocarbon chain through ester linkage. C=c double bonds = unsaturated fatty acids: one double bone = monounsaturated fatty acid o. Two or more double bond = polyunsaturated fatty acid: double bond is in cis configuration = causes kink in structure of chain, unsaturated fatty acids do not pack as close together as saturated ones. Ester which both alcohol and fatty acid have long hydrocarbon chains. Insoluble in water due to non-polar nature of hydrocarbon chains. Triacyclglycerols: neutral fats or oils o.
