قناة سنة ثانية بشري (دفعة 53)

7. Fatty Acid Nomenclature • Carbon numbering starts from COOH carbon = C1 • Adjacent carbon = α (C2), next = β (C3) • Example: • Oleic acid: 18:1 Δ9 • 18 carbons • One double bond • Between C9 & C10 8. Essential Fatty Acids (EFA) Definition PUFA that cannot be synthesized in humans because enzymes cannot introduce double bonds beyond carbon 9. Types • Linoleic acid (ω6) • Linolenic acid (ω3) • Arachidonic acid Importance • Essential for growth • Prostaglandin synthesis • Cholesterol metabolism • Cell membrane integrity Sources • Vegetable oils (corn, sunflower, soybean) • Fish oils (ω-3 PUFA) 9. Desaturation of Fatty Acids • Occurs in smooth endoplasmic reticulum • Enzymes: • Δ9, Δ6, Δ5 desaturases • Humans lack Δ12 & Δ15 desaturases • Plants can synthesize PUFA

5. Simple Lipids (Triglycerides) • Structure: Glycerol + 3 fatty acids • Types: • Simple TAG (same FA) • Mixed TAG (different FA) • Solid at room temp → fats • Liquid at room temp → oils Importance of Glycerol • Used in pharmaceuticals & cosmetics • Nitroglycerin → vasodilator in coronary artery disease 6. Fatty Acids (FA) General Characteristics • Long hydrocarbon chain + terminal –COOH • Monocarboxylic • Usually esterified • Free FA transported bound to albumin Classification of FA A. According to Saturation Saturated FA • No double bonds • Formula: CH₃–(CH₂)n–COOH • Examples: • Palmitic acid (16:0) • Stearic acid (18:0) Unsaturated FA • One or more double bonds • Monounsaturated: • Oleic acid (18:1 Δ9, ω9) • Palmitoleic acid (16:1 Δ9) • Polyunsaturated (PUFA): • Linoleic (18:2 Δ9,12 ω6) • Linolenic (18:3 Δ9,12,15 ω3) • Arachidonic (20:4 Δ5,8,11,14 ω6) B. According to Chain Length • Short chain: 2–4 C • Medium chain: 6–10 C • Long chain: 12–26 C

3. Functions of Lipids • Dietary energy source • Energy storage as triacylglycerol (TAG) • Supply essential fatty acids • Structural components of: • Plasma membrane • Intracellular membranes • Absorption of fat-soluble vitamins A, D, E, K • Lipid transport via HDL, LDL, VLDL, Chylomicrons • Synthesis of: • Steroid hormones • Prostaglandins 4. Classification of Lipids A. Simple Lipids Esters of fatty acids with alcohols: • Fats: FA + glycerol • Waxes: FA + alcohol other than glycerol B. Compound Lipids Simple lipids + non-lipid group: • Phospholipids • Glycolipids • Lipoproteins C. Derived Lipids Formed by hydrolysis: • Steroids (cholesterol, hormones) • Ketone bodies • Bile acids

Lipid Chemistry 1. Definition of Lipids Lipids are a heterogeneous group of biologically important organic compounds that are: • Insoluble in water • Soluble in non-polar organic solvents (ether, chloroform, benzene, acetone, hot alcohol) 2. Clinical Applications & Importance • Excess fat → Obesity → ↑ risk of myocardial infarction • Abnormal cholesterol & lipoprotein metabolism → Atherosclerosis & cardiovascular diseases • In Diabetes Mellitus: • Disturbed fatty acid metabolism • ↑ Ketone bodies → Diabetic Ketoacidosis (DKA) • Lipids are stored in adipose tissue • Lipoproteins transport lipids in blood • Lipid biochemistry is essential for understanding: • Obesity • Diabetes Mellitus • Atherosclerosis • Nutrition & PUFA

هيا lipid خت فت 🥲 بروتين تعبني وما نسخش الكلام .

هكي كملنا الشيت . موفقيين شباب ♥️.