Biochemistry 301 UW Madison: Exam 2b Study Guide.

©FYNDLAY EXAM SOLUTIONS 2024/2025 ALL RIGHTS RESERVED. 1 | P a g e Biochemistry 301 UW Madison: Exam 2b Study Guide. Great bulk of lipids in organisms are... - answertriglycerides or triglycerols general structure of a fatty acid - answercarbon chain + carboxyl group on end source of triglycerides - answerthe diet, de novo biosynthesis in the liver, and storage deposits in adipocytes Bile salts - answer- cholesterol derivatice - detergent substances synthesized by the liver - stored in gallbladder - essential for digestion of lipids and their absorption through intestinal mucosa cholic acid - answerprimary bile acid (bile salt) bile salts association with triacyglycerol - answerhydrophobic side of bile salt associates with triacyglycerol and forms a micelle. Lipoproteins - answernoncovalent lipid-protein complexes that allow movement of lipids through aqueous environments such as blood and lymph free lipids are - answerundetectable in the blood Apolipoproteins - answerthe protein components of lipoproteins four major classes of lipoproteins - answerchylomicrons, VLDL, LDL, HDL the higher the lipid content... - answerthe lower the density the higher the protein content... - answerthe higher the density chylomicrons - answertransport dietary fat from the intestine to peripheral tissues VLDLs - answercomparable role for triacylglycerols synthesized in the liver ©FYNDLAY EXAM SOLUTIONS 2024/2025 ALL RIGHTS RESERVED. 2 | P a g e LDLs - answerplay a major role in transporting cholesterol to tissues HDLs - answerplay a major role in returning excess cholesterol from tissues to the liver for metabolism or excretion Components of lipoproteins - answertriacylglycerols, protein, phospholipids, free cholesterol, and cholesterol bound to fatty acids synthesis of fatty acids is in the - answercytoplasm breakdown of fatty acids is in the - answermitochondra fatty acid oxidation pathway - answer- activation of the carboxyl group on the fatty acid (via ATP) - transport into the mitochondrial matrix - stepwise oxidation, 2 carbons at a time fatty acids in the cytosol arise from - answer1. de novo biosynthesis 2. hydrolysis of triacylglycerols 3. transport of fatty acids from fat storage cells oxidation pathway: steps of activation and transport - answer* starting with a free fatty acid * 1. activation via adenylation 2. transfer to carnitine 3. transport through the mitochondrial membrane 4. reconjugation with CoA oxidation pathway: steps of beta oxidation - answer* fatty acid is now in the mitochondrial matrix * 1. dehydrogenation 2. hydration 3. dehydrogenation 4. thiolytic cleavage, yielding acetyl-CoA plus a fatty acyl-CoA two carbons shorter than the original CPT 1 - answerAttaches carnitine to FA-CoA to generate Fatty Acyl Carnitine ©FYNDLAY EXAM SOLUTIONS 2024/2025 ALL RIGHTS RESERVED. 3 | P a g e Note: CoA removed - can now cross the outer membrane CPT 2 - answerRemoves Carnitine from FA-Carnitine. Also adds CoA to FA. FA-CoA will be used in Beta Oxidation - now in the mitochondrial matrix what inhibits CPT 1 - answerMalonyl CoA carnitine - answercarrier that shuttles fatty acids into the mitochondria two carbon chains are removed as - answeracetyl-CoA and transferred to the CAC. omega-3 fatty acids - answerpolyunsaturated fatty acids - double bond at the 3rd carbon ex. linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid omega-6 fatty acids - answer- double bond at the 6th carbon ex. linoleic acid, and arachidonic acid - arachidonic acid can be make from linoleic acid - potentially not as healthy as omega 3 fatty acids oxidation of one double bond requires - answer1 enzyme oxidation of multiple double bonds requires - answer2 enzymes enzyme for oxidation of monounsaturated fatty acids - answerenoyl-CoA isomerase extra enzyme needed for polyunsaturated fats - answer2,4-dienoyl-CoA enoyl-CoA isomerase - answerRearranges cis double bonds at the 3,4 position to trans double bonds at the 2,3 position hydratase in fat oxidation - answeradds a water to remove the double bond products from odd-numbered fatty acid oxidation - answeracetyl-CoA and propionyl-CoA propionyl-CoA oxidation - answer- add CO2