HUN 3224 Test 3 Study Guide Lipids Intro to Lipids Digestion and Absorption 1 Know the concepts surrounding fatty acids saturation cis versus trans configurations nomenclature chain length essentiality a Fatty Acids straight hydrocarbon chain ex CH3 CH2 CH2 CH2 CH2 CH2 COOH i Methyl Hydrophobic ii COOH Hydrophilic b Chain Length i 4 24 Carbon Length ii Most are even c Saturation 1 14 or more more nutrients i Saturated SFA no double bonds ii Monounsaturated MUFA 1 double bond iii Polyunsaturated PUFA 2 or more double bonds 1 Double Bonds have 3 carbons between them d CIS versus TRANS i e Hydrogenation adding Hydrogen to unsaturated fats f Essential Fatty Acids Lack enzymes to put double bonds on beyond 9th carbon i Linoleic Acid 18 2w6 ii A Linolenic Acid 18 3w6 g Nomenclature see 2 2 Be able to name fatty acids a CH3 CH2 CH2 CH2 CH2 CH2 CH2 COOH i Methyl Omega or n end ii COOH Alpha end b Nomenclature Steps i Count of Cs ii Count of Double Bonds iii Name According to omega or alpha end c Example From Omega End 18 2w6 or 18 2n6 18 of carbon bonds 2 of double bonds w6 double bonds start from the 6th carbon on omega end From Alpha End 18 2 9 12 18 2 9 12 18 of carbon bonds 2 of double bonds 9 12 Location of double bonds from Alpha end 3 Know the functions and examples of eicosanoids sterols and phospholipids a Eicosanoids hormone like controls blood pressure platelet aggregation immune system nervous system smooth muscle contraction i Prostacyclins Thromboxanes Lekotrienes prostaglandins b Triglyceride storage form of fats composed of Glycerol Backbone Fatty Acid c Phospholipids Composed of Phosphate Glycerol Backbone Fatty Acid d Glycolipid Lipid Carbohydrate e Steols Cholesterol i Bile acids ii Sex hormones iii Adrenocortical hormones iv Vitamin D 4 Be able to discuss lipid absorption into and out of the enterocyte a Micelles are form from Fatty elements and Fat soluble vitamin surround by bile salts and are passively diffuse at duodenum and jejunum i Long chains fatty components and proteins form chylomicrons and transported via lymph ii Short chain med chain glycerol are transported via blood Lipoproteins 1 Be able to describe the formation function and breakdown of a chylomicron 2 Know the relationship between density size and protein for lipoproteins 3 Know the formation and function of each lipoprotein a See Chart 4 Know the role of the enzymes LCAT and LPL a Lecithin cholesterol acyltransferase LCAT i Allows HDL to pick up cholesterol from cell membranes or from other lipoproteins ii Apo A1 binds to LCAT receptor iii Cholesterol Cholesterol Ester iv Phospholipid lyoslecithin v HDL transports CE to tissue vi Lysolecithin binds to albumin b Lipoprotein Lipase LPL i Hydrolyzes TG to free fatty acids and glycerol ii Free Fatty Acids and glycerol absorbed into tissues LipoproteinFormationFunctionSizeCompositionChylomicronSynthesis in enterocyes from exogenous lipids 1 transports exogenous triglycerides to tissues 2 Lipoprotein Lipase90 100nm largest and least denseApoproteins A B C E Triglycerides PL CholesterolVLDLsynthesized in liver released into blood1 transports endogenous lipid from liver to extra hepatic tissues 2 Lipoprotein Lipase30 90nmApoprotein B C Triglyceride Cholesterol PhospholipidsIDLfrom VLDL after triglyceride hydrolysis fromed into LDL vid Lipoprotein lipasen an aLDLfrom IDL after triglyceride hydrolysis1 delivers cholesterol to non hepatic tissues 2 uptake via receptor mediated endocytosis20 25nmapoproteins B 100 triglyceride cholesterol phospholipidsHDLLiver and Intestine1 removals of cholesterol from non hepatic tissues 2 lecithin cholesterol acyltransferase LCAT 5 25nmApoprotein A C D E triglyceride cholesterol phospholipid 5 Be able to fully explain receptor mediated endocytosis a Receptors are located in clatharin coated pits and are specific for proteins LDL with apoprotein B 100 b LDL and receptor bind and internalize to form a vesicle inside the cell c Lysosome changes pH ApoB is degraded to amino acids and cholesterol released into cells d Receptor returns to surface 1 Cholesterol know the key steps in formation regulation transportation and Cholesterol Bile acids functions a Formation HMG CoA reductas NADPH NADP 2ATP 2ADP NADPH NADP Squalene Synthase b Regulation i HMG CoA reductase Activity 1 Rate Limiting Enzyme 2 Reduced by a Cholesterol b Fasting c Glucagon d Clucocorticoid Hormones ii Dietary Cholesterol 1 High dietary cholesterol lowers synthesis 2 Low dietary cholesterol increases synthesis iii Transportation iv Functions 1 HDL transports cholesterol from tissue to liver 2 LDL transport cholesterol form liver to tissue 1 Cell Membrane maintains fluidity 2 Steroid Hormone testosterone androgens estrogen progesterone 3 Vitamin D 4 Bile 2 Bile know the synthesis role and regulation of bile understand the enterohepatic circulation of bile a Synthesis i Hepatocytes CCK secretin gastrin ii Stored in Gall Bladder iii CCK stimulates release from gall bladder through sphincter of Oddi into duodenum via bile duct b Function i Lipid emulsification ii Essential for fat digestion c Enterohepatic Circulation of Bile 3 Understand how statins and bile acid sequestrants lower cholesterol a Statins block an enzyme the body needs to make cholesterol b Bile Acid Sequestrants force bile out of the body via stool reducing the amount of bile reabsorbed the body then must make more bile from cholesterol causing cholesterol to be lowered Fatty Acid Synthesis 1 Be able to describe the process of elongation and where those reactions take place a 2 Understand the enzyme fatty acid synthase a Fatty Acid Synthase a system of enzymes that catalyze fatty acid synthesis i Thioesterase acyl carrier protein ketoacyl reductase enoyl reductase hydratase transcyclases ketoacyl synthase 3 Understand the enzymes responsible for the desaturation of fatty acids a Desaturase uses NADPH H 2H2O NADP and creates a double bond on fatty acid Beta Oxidation 1 Know in detail and be able to describe the oxidation of an even and odd fatty acid including the amount of energy produced and where all the ATP s come from a Beta Oxidation breakdown of long chain fatty acids for energy b Process 1 Long Chain FA CoA 2ATP Thiokianse Fatty Acyl CoA 2 Fatty Acyl CoA carnitine acyl transferase I Carnitine i In Cytosol Acylcarnitine ii In mitochondria 1 Acylcarnitine Carnitine Acel Transferase II Fatty Acyl Coa Carnitine goes back to cytosol 2 Fatty Acyl CoA FAD H Enoyl CoA FADH 3 Enoyl CoA H2O B
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