Metab I Lipids I Lipids Fatty acids Phospholipids Sterols Cholesterol etc A Fatty Acids 4 24 Carbons Long 1 Straight Chain Hydrocarbon chain 2 3 Greater than 12 carbons LONG 4 Less than 12 MEDIUM SHORT 5 6 Most are even numbers of carbons 14 or more carbons are nutritionally significant B Saturation 1 Unsaturated Fatty Acids at least one carbon carbon double bond C C 2 Saturated Fatty Acids a All Carbons are saturated with hydrogens b No double bonds c Solid at room temperature 3 Monosaturated Fatty Acids a One double bond C C b Ex Olive Oil Canola Oil 4 Polysaturated Fatty Acids a Multiple double bonds form predominant opposed to trans b Cis c Ex Safflower Sunflower Corn etc C Hydrogenation ex cisco 1 Adding hydrogens to an unsaturated fat to make it a solid at room temperature 2 Often used in commercially processed foods a Ex crackers cookies snack cakes etc 3 Forms TRANS fat 4 5 Supporting Point D Nomenclature 1 a Count the Number of C s 2 Ch3 end omega n 3 COOH alpha delta sign 4 Steps 1 18 carbons 1 2 1 18 2n 2 18 2 9 12 b Count the Number of Double Bonds c Name According to omega or alpha end E Essential Fatty Acids 1 Linoleic Acid 18 2w6 or 18 2delta 12 2 Alpha Linolenic Acid 18 3w3 or 18 3delta9 12 15 3 We lack the enzymes to add C C beyond delta 9 4 General Guidelines a Men 16 17g omega 6 1 6g omego 3 b Women 11 12g omega 6 1 1g omega 3 F Eicosanoids made from essential FA made and used in cell 1 Hormone Like substance 2 modulation of a Blood pressure b Platelet aggregation c Immune system d Nervous system e Smooth muscle contraction blood pressure 3 Be aware that elongase adds 2 carbons and desaturase adds a C C double bond will help later G Families 1 Prostacyclins member of the family of lipid molecules known as eicosanoids It inhibits platelet activation and is also an effective vasodilator 2 Thromboxanes another member of the eicosanoids family named for role in clot formation thrombosis 3 Leukotrienes another member of the eicosanoids mostly involved with immune system trigger contractions in the smooth muscles lining the bronchioles their overproduction is a major cause of inflammation in asthma and allergic rhinitis 3 Leukotriene antagonists are used to treat these disorders by inhibiting the production or activity of leukotrienes a Ex medication for asthma such as nasonex inhibits lipoxygenase a member of leukotrienes family that inhibits formationof leukotrienes lipoxsis 4 Very important to be aware that eicosanoids characteristics depend on the location in the body H Synthesized from 1 Arachidonate Acid 20 4 w6 2 Eicosatrienoic Acid 20 3w6 3 Eicosapentanoic Acid 20 5 w3 in fish I Triglycerides ate and stored when we eat fat usually in form of TG triglycerides 1 Glycerol Backbone three carbon chain 2 Three Fatty Acids which vary and length and saturation 3 J Phospholipids recall that every cell has a phospholipid bilayer so phospholipids are very important all cell membranes lots of Fatty Acids 4 DHA 1 Glycerol Backbone 2 One or more fatty acid 3 One phosphate 4 K Glycolipids basically phospholipid without phosphate instead a CHO 1 Lipid and a carbohydrate 2 Glycolipids are found in cell for signalling L Sterols not fatty acid a ring structure attaches to FA to cholesterol 1 Steroid Nucleus 2 Cholesterol a Bile acids b Steroidal sex hormones c Adrenocortical hormones d Vitamin D e II Lipid Digestion A Lingual Lipase 1 Secreted at base of tongue 2 Stable to low pH 3 Efficient digestion of milk fat a Ex infants B Biliary Emulsification 1 Emulsification a Dispersion of fat in an aqueous solution b Allows for lipase action 2 Bile salt an emulsifying agent 3 Bile made in liver and stored in gallbladder 4 Bile is necessary because the fat is hydrophobic and the enzymes needed to break it down are hydrophilic So the fat is floating at the top in small intestine and enzyme is near bottom Bile is perfect because it is part hydrophobic which attaches to the fat and part hydrophilic which will bind to water Pulls fat down allows enzymes to attach fat to glycerol and FA 5 Watch this http www youtube com watch v x4gCyCptsY4 C Lipolysis 3 main enzymes see drawing 1 2 Pancreatic Lipase 3 Cholesterol Esterase 4 Lechithinase 5 III Lipid Absorption A Michelle Formation 1 Fatty elements and fat soluble vitamins surrounded by bile salts 2 Passive Diffusion of fatty elements vitamins the distal duedenum and jejuneum 3 Bile Salts absorbed in illeum and returned to liver via EHC Inside the Enterocyte recall cells that lines gut B 1 Long chain fatty acids greater than 12 carbons and other fatty components they require Co enzyme A 2 Reformation of Triglyerides cholesterol esters and phospholipids 3 Triglycerides Fatty Componenets Proteins Chylomicron 4 Short chain fatty acids simply attach to albumin C Lipoproteins complexs that carry lipid products in the blood and lymph to various tissues think of taxi driver 1 Chylomicron a Formation 1 Synthesis in enterocytes from exogenous lipids 2 Released into lymph b Composition 1 Mostly triglycerides 80 c Size d Function 1 Largest lipoprotein with lowest density not important 1 Transports exogenous triglycerides to tissues 2 Lipoprotein Lipase LPL a Hydrolyzes triglycerides to free fatty acids and glycerol b Free fatty acids and glycerol are absorbed into the tissues e Chylomicron Remnant 1 Remains after Triglyceride Hydrolysis 2 Taken up by hepatocytes liver cells via receptor mediated endocytosis basically ingested by liver cells 2 Very Low Density Lipoprotein VLDL a Formation 1 Synthesized in the liver by endogenous triglycerides 2 Released into the blood b Composition 1 c Size 1 30 90nm d Function 1 Transports endogenous lipid from liver to extra hepatic tissues 2 Lipoprotein Lipase LPL a Hydrolyzes triglycerides to free fatty acids and glycerol b Free fatty acids and glycerol are absorbed into tissues 3 Intermediate Density Lipoprotein IDL a Formation 1 From VLDL after triglycerdies hydrolysis 2 Transient very short lived 1 Formed into LDL after Triglycerides Hydrolysis via LPL 4 Low Density Lipoprotein LDL b Function a Formation b Function c Composition d Size 1 From IDL after Triglycerdies hydrolysis 1 Delivers cholesterol to non hepatic tissues 2 Uptake via receptor mediated endocytosis D Receptor Mediated Endocytosis involved in chylomicron remnants and LDL 1 Receptors located in clatharin coated pits 2 Receptors are specific for proteins ex apoB 100 for LDL 3 LDL and receptor bind 4 Receptor and LDL complex internalized a Form
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