Lipid Notes PDF

LIPID SOFEE AKHLAK Learning objectives 1. Define lipid 2. State the functions of lipids 3. Explain the types of lipids found in human body 4. Describe the fate of lipid LIPID ✓Lipids are made up of carbon, hydrogen, and oxygen atoms with lower proportion of oxygen than carbohydrate ✓Ins...

LIPID SOFEE AKHLAK Learning objectives 1. Define lipid 2. State the functions of lipids 3. Explain the types of lipids found in human body 4. Describe the fate of lipid LIPID ✓Lipids are made up of carbon, hydrogen, and oxygen atoms with lower proportion of oxygen than carbohydrate ✓Insoluble in water Functions of lipids Fatty Acids ✓Simplest form of lipid ✓Used to synthesize triglyceride and phospholipid ✓Can be catabolised to generate ATP Fatty Acids FATTY ACID SATURATED UNSATURATED Fatty Acids ❑Saturated Fatty Acid ✓Single covalent bond between carbon atoms ✓Saturated with hydrogen atoms ✓Causes atherosclerosis (changes in blood vessel) Fatty Acids ❑Unsaturated Fatty Acid ✓Double covalent bond between carbon atoms ✓Not completely saturated by hydrogen atoms ✓The carbon chain has a kink (bend) at the side of double bond Fatty Acids UNSATURATED MONOUNSATURATED POLYUNSATURATED Fatty Acids MONOUNSATURATED POLYUNSATURATED ✓One kink ✓More than one kink Triglycerides ✓Most plentiful lipid in human body and diet ✓A fat is a triglyceride ✓Consist of ONE glycerol molecule and THREE fatty acid molecules Triglycerides ✓Three carbon glycerol molecule form the backbone of a triglyceride ✓Three fatty acids are attached by dehydration synthesis , one to each carbon of glycerol backbone Triglycerides ✓Ester linkage - chemical bond formed between glycerol molecule and fatty acids when water is removed (dehydration synthesis) ✓Hydrolysis – breakdown of a single molecule of triglyceride into 3 fatty acids and glycerol Triglycerides ✓Solid @ liquid at room temperature ✓Mainly consist of saturated fat ✓Red meat, whole milk, butter, palm oil, coconut oil The hydrocarbon chain closely pack together and solidify at room temperature Diet high content in saturated fat – heart disease and colorectal cancer Triglycerides ✓Oil – triglyceride - liquid at room temperature ✓Unsaturated fatty acids ✓The kinks at the site of double bond prevent them from closely packing together – liquid at room temperature Triglycerides ✓Can be monounsaturated and polyunsaturated ✓Monounsaturated – olive oil, peanut oil, canola oil ✓Polyunsaturated – corn oil, safflower oil, sunflower oil, soybean oil, fish oil ❖Both monounsaturated and polyunsaturated fats are believed to decrease risk of heart disease Phospholipid ✓Have a glycerol backbone and TWO fatty acid chains attached – tail – non polar (hydrophorbic) ✓They contain phosphate and nitrogen – head – polar (hydrophilic) ✓They make up cell membrane Phospholipid Steroids Steroids ❑Common steroids in body: ✓Cholesterol – required for cell membrane structure, precursor for sex hormones ✓Estrogen Sex hormones ✓Testosteron ✓Cortisol – maintain normal blood sugar level ✓Bile salt – lipid digestion and absorption ✓Vitamin D – bone growth Other lipids 1. Eicosanoids ✓20 carbon fatty acids called arachidonic acid ✓2 types: a. Prostaglandins b. Leukotrienes ✓Modify response to hormones, inflammatory response, allergic response, prevent stomach ulcer, dilate airway to the lungs, regulate body temperature, influence formation of blood clots Other lipids 2. Fat soluble vitamins ✓Beta carotene (yellow pigment of egg yolk, carots, tomatoes) converted to vitamin A ✓Vitamin D, E, K and lipoprotein The fate of lipids 1. Oxidized to produce ATP 2. Stored in adipose tissue 3. Phospholipids are used to synthesize cell membrane 4. Lipoproteins used to transport cholesterol in blood 5. Thromboplastin needed for blood clotting 6. Myelin sheaths which speeds up nerve conduction END