Lipid Notes PDF

# Lipid - A biomolecule that is only soluble in organic/fat/nonpolar solvents, but insoluble in water. - Collective term for fixed oils, fats, waxes and hormones. - Organic compounds that contain hydrocarbons which are the foundation for the structure and function of living cells. ## Two Major Cl...

# Lipid - A biomolecule that is only soluble in organic/fat/nonpolar solvents, but insoluble in water. - Collective term for fixed oils, fats, waxes and hormones. - Organic compounds that contain hydrocarbons which are the foundation for the structure and function of living cells. ## Two Major Classes of Lipid - **Nonsaponifiable lipid** - cannot be broken up into smaller molecules by hydrolysis. - **Saponifiable lipid** - contains one or more ester groups allowing it to undergo hydrolysis in the presence of an acid, base, or enzyme. ## Biological Significance ### Biology - Liposomes - Cell Structuring - Compartmentalization. - Lipid Metabolism Bio-Synthesis. - Organ Protection. - Self-assembly. - Membrane Protein Crystallization. - Hierarchically Ordered structures. ### Foods - Oil - Fruits/Nuts - Dairy products. - Eggs - Meat. ### Applications - Medicines - Cosmetics ## Properties of Lipids - Greasy to touch, leaves a permanent oily stain on paper. - Lighter than water. - Soluble in organic solvent, insoluble in water. - When pure, colorless with bland odor and taste. - Yellow color in fat is due to carotene (provit. A). - Undergoes decomposition forming acrid flammable vapors. Acridity is due to acrolein (propenal). ## Physical Constants of Lipids 1. **Refractive index** - increases with increasing chain length and increasing unsaturation. 2. **Melting/solidification point** - Lipids melt and solidify over a temperature range because of the mixture of fatty acids.  3. **Viscosity** - In biology, membrane fluidity refers to the viscosity of the lipid bilayer of a cell membrane or a synthetic lipid membrane. Lipid packing can influence the fluidity of the membrane. 4. **Specific gravity** - The specific gravity of the fats is less than 1 (about 0.86) and, therefore, they float on water surface. 5. **Optical rotation** - is the ability of the compound to rotate plane polarized light to the right or to the left. ## Classification of Lipids ### Lipids - **Simple Lipids** - **Fats & Oil** - Simple - Mixed - **Waxes** - **Compound Lipids** - **Phospholipids** - Lecithin - Cephalin - Plasmalogen - Sphingomyelin - **Glycolipids** - Cerebrosides - Gangliosides - **Derived Lipids** - **Alcohol** - **Fatty Acids** - **Sterols** - **Isoprenoids** - Terpenoids - Carotenoids - **Sulfolipids** ## Lipids Storage Disease Lipid storage diseases, or the lipidoses, are a group of inherited metabolic disorders in which harmful amounts of fatty materials (lipids) accumulate in various cells and tissues in the body. People with these disorders either do not produce enough of one of the enzymes needed to break down (metabolize) lipids or they produce enzymes that do not work properly. ### Histiocytosis X (Hand-Schuller Christian Syndrome) - Also known as Chronic Disseminated (LCD). - Specific clinical triad of lytic bone lesions. - Exophthalmos - Diabetes insipidus. ### Signs and Symptoms of Niemann-Pick Disease - Abdominal swelling within 3-6 months. - Loss of Appetite. - Loss of early motor skills. - Enlarged spleen & liver - Jaundice at birth - Irregular speech. ### Hand-Schuller Christian Disease - Abnormal high concentration of cholesteryl ester deposits in the liver, brain, kidneys, nerves and other tissues of the body. - Belongs to the spectrum of disorders, now known as "eosinophilic granulomatosis" or "Langerhans cell granulomatosis". ### Phingomyelin lipidosis / Niemann-Pick Disease - Due to the inability to degrade sphingomyelins as a result of a deficiency in the enzyme sphingomyelinase. ### Acute Neuronopathic Gaucher Disease (Type 2) - Strabismus - Retroflexion of the neck - Cortical thumbs - Visceromegaly - Failure to thrive - Cachexia ### An autosomal recessive due to inability to degrade glucocerebrosides as a result of a deficiency in the enzyme glucocerebrosidase. - The result of a build up of certain fatty substances in certain organs, particularly your spleen and liver. This causes these organs to enlarge and can affect their function. ## Krabbe's Disease / Galactocerebrosidosis ### What is Krabbe Disease - Brain damage - Cataracts - Jaundice - Enlarged liver - Kidney damage - If a galactosemic infant is given milk, unmetabolized milk sugars build up and damage the liver, eyes, kidneys and brain. ### Due to the inability to degrade galactocerebrosides as a result of a deficiency in the enzyme Galactocerebrosidase. - A disease is an inherited disorder that destroys the protective coating (myelin) of nerve cells in the brain and throughout the nervous system. ## TaySachs Disease ### Tay-Sachs disease Genetic Disorder Begins - 6 months - Damage - Brain Cells - Spinal Cord - Neurons - Baby - Loosing ability to: - Turn over - Sit - Crawl - Seizures. - Hearing loss. - Inability to move. - Death - Before 4-6 Years ### A rare genetic disorder passed from parents to child. - It's caused by the absence of a Gangliosidase enzyme that helps break down fatty substances. These fatty substances, called gangliosides, build up to toxic levels in the brain and spinal cord and affect the function of the nerve cells.