LIPIDS Daniel Bučánek Jan Gembík

Lipids Fatty acids Glycerides Nonglycerol lipids Complex lipids

Types of lipids Fatty acids Saturated Unsaturated Glycerides Neutra Phospoglycerides Nonglycerides Sphingolipids Steroid Waxes Complex lipids Lipoproteins Glykolipids

Lipid functions Cell membrane structure Creates a barrier for the cell Controls flow of materials Energy storage Fats stored in adipose tissue Hormones and vitamins Hormones – communication between cells Vitamins – assist in the regulation of biological processes

Fatty acids structure CH3(CH2)nCOOH Long chain monocarboxylic acids Size range: C12 – C14 Always an even number of carbon Saturated – no double bonds Unsaturated – one or more double bonds

Fatty acids structure Saturated Unsaturated cis trans

Some common fatty acids Common name IUPAC name MP °C Formula Presence of double bonds reduced melting point. In nature, all double bonds are ´cis´.

Steric acid Oleic acid

Reactions of fatty acids React like any other carboxylic acid.

Unsaturated fatty acids eicosanoids All are unsaturated. All have twenty carbons. Some are essential fatty acids Can´t be produced by the body. examples: linoleic and linoleic acids Three groups: prostaglandins, leukotrienes, thromboxanes

Prostaglandins Originaly isolated from seminal fluid. All are derived from arachidonic acid.

Prostaglandins

Prostaglandins Biological effect Stimulation of smooth muscles Regulation of steroid production Inhibition of gastric secretion Inhibition of hormone-sensitive lipases Inhibition / stimulation of plate aggregation Regulation of nerve transmission Sensitization of pain Mediation of inflamantory response

Blood clotting Thromboxane A2 Produced by platelets in blood. Stimulates constrictions of blood vessel. Aggregation of platelets. Prostacyclin Produced by cells that line blood vessels. Reverses effects of throbmoxane A2 Aspirin therapy Acts as anticoagulent – antiplatelet aggregation.

Inflammantory response Protective mechanism when tissue is damaged. Ressults in swelling, redness, fever and pain. Prostaglandins promote this response. Drug like aspirin and ibuprofen Anti - inflammatories Block prostaglandins synthesis Cause reduction in this response

Neutral glycerides Ester of glycerol and fatty acid. Principal function is energy storage – fat or oil.

Fats and oils Both are triglycerides Fats typically obtained from animals solids at room temperature made from saturated fatty acids Oils typically obtained from plants liquids at room temperature made from unsaturated fatty acids

Waxes Water insoluble and hard to hydrolyze Often used to provide a protective coating (leaves, skin, fur, hair….) Bees wax and Sebum are examples Ester of a fatty acid and a long chain alcohol

Phospoglycerides Lipids that contain a phosphate group. Modified fat where a phospate replaces one of the fatty acid chain. Uses production of cell membrenes emulsifying agents Lecithin-phosphatidylcholin Polar head Nonpolar tail

Nonglycerol lipids Sphingolipids A type of phospolipid not derived from fat. Used primarily in nerve tissue – myelin sheath. In people, 25% of all lipids are sphingolipids.

Steroids Broad class of compounds that all have the same base structure. Cholesterol Principal membrane lipid for fluidity.

Complex lipids Lipids bound to other molecules Combination results in the structure

Complex lipids Four major classes of plasma lipoproteins Chilomikrons Very low-density lipoproteins (VLDL) Low-density lipoproteins (LDL) High-density lipoproteins (HDL) Each is composed of several types of lipids

Composition of complex lipoproteins

Composition of complex lipoproteins

Function of lipoproteins Chilomikrons Transport triglicerides from intestines to other tissue – except kdneys VLDL Bind triglycerides in liver and carry them to fat tissue LDL Carry choresterol to peripheral tissue HLD Bound to plasma choresterol Transport cholesterol to liver

Transport of lipoproteins

Source Some information from internet. Some information from lecture of Biochemistry. And some information from 12.Lesson with name Biochemistry.