Lipids 2 - Study Notes PDF

QS What are the common functions of Phospholipids? ACEPH A: 1. Amphipathic molecules (polar and nonpolar groups) —> form micelles in water 2. Cell membrane fluidity: form phospholipid bilayer —> USFA has kinks because of double bonds —> keeps the FA away from eachother —> membrane fluidity. SFA —...

QS What are the common functions of Phospholipids? ACEPH A: 1. Amphipathic molecules (polar and nonpolar groups) —> form micelles in water 2. Cell membrane fluidity: form phospholipid bilayer —> USFA has kinks because of double bonds —> keeps the FA away from eachother —> membrane fluidity. SFA —> interacts strongly together —> lesser fluidity 3. Emulsification of fat (large fat globule —> fine droplets —> easily digested) 4. Plasma protein formation 5. Hydrotropic substances —> prevents precipitation of cholesterol 6. Arachidonic acid for synthesis of Eicosanoids What are the specific functions of Phospholipids? 2L 3P BC 1. Lecithin provides choline for synthesis of acetylcholine (neurotransmitter) 2. Lecithin is a lung surfactant 3. Plasmalogens are present —> reduced level. is associated with Alzheimier’s 4. Phosphatidyl glycerol is important in synthesis of cardiolipin 5. Phosphatidyl inositol acts as hormone second messenger (signal transduction) 6. Blood clotting functions: Platelet Activating Factor is a choline Plasmalogen, Cephalin increases thrombin formation 7. Cardiolipins are involved in mitochondrial energy metabolism How does Lecithin work as a lung surfactant? ⁃ Reduces tension between air and alveolar membrane ⁃ Deficiency of Lecithin leads to Respiratory Distress Syndrome RDS ⁃ Lecithin/Sphingomyelin ratio shows fetal lung maturity ⁃ Stays equal till 32-33 weeks —> after, Lecithin becomes more ⁃ L/S ratio. above 2 —> fetal lung maturity ⁃ L/S ratio less than 1.5 —> RDS What is the compound of Glycolipids? Ceramide (sphingosine + FA) + Carbohydrate What kind of Glycolipids are there? Cerebrosides (ceramide + glucose/galactose) —> gluco-/galactocerebroside Sulfolipids (sulfatide) (ceramide + galactose 3 sulfate) Ganglioside (ceramide + complex carb. radicals) Where is Cerebroside found in the body? Brain tissue Where are Sulfolipids found? Liver, muscles, testicles What are derived lipids? Hydrolysis of simple/compound lipids What are examples of derived lipids? FA, alcohols, steroids, carotenoids, fat solube vitamins What are steroids divided into? Sterols, bile acids, steroid hormones What sterol is found in animals/ humans and in what from is it found? Zoosterols and it is found as cholesterols What are the sources of Cholesterol? exogenous: brain, egg yolk, liver, meat endogenous: RBC’s and every cell can synthesize its own cholesterol What is the distribution of Cholesterol? In all tissues but especially in nervous tissue, liver, adrenals, gonads Where is plasma cholesterol synthesized? in the liver 120-200mg/dl (30% cholesterol, 70% cholesterol ester What is the importance of Cholesterol? 1. forms bile acids/salts in liver 2. forms steroid hormones 3. forms Vitamine D3 (Cholecalciferol) 4. it moderates membrane fluidity How does Cholesterol moderate membrane fluidity? It prevents the movement of FA tail at high temperatures It prevents close packing of phospholipids at low temperatures