Easy Biochemistry Notes

 Deficiency of Essential fatty acids causes Phrynoderma it is also called as toad skin Clinical Features -  Eczema Hyperkeratosis - horny eruptions on the limbs,back & buttocks Loss of hair Poor wound healing Gonadal dysfunction

  1.AMPHIPATHIC NATURE –   Phospholipids have both hydrophobic & hydrophilic portion in the molecule and so are amphipathic in nature In lecithin - Choline, Phosphate and glycerol form the hydrophilic head and fatty acids form the hydrophobic tail 2.MICELLE FORMATION – When Phospholipids are distributed in water – hydrophobic parts keep away from water forming molecular aggregates called micelle Involved in stabilization of lipids in aqueous medium Helps in digestion & absorption of lipids 3.BIOMEMBRANES Bilayer of phospholipids formed by orientation of polar heads(hydrophilic) to the aqueous phase on both side & non polar tails (hydrophobic) to the interior. FA’s with more than 6 carbon atoms form monolayers 4.LIPOSOMES Microscopic spherical particles prepared by sonication of mixture of phospholipids & cholesterol are called as liposomes. Drugs, proteins, enzymes, genes, etc. may be encapsulated by the liposomes Liposomes act as carriers for thes...

 Definition - Made of aliphatic carboxylic acids with hydrocarbon chain have the general formula, R—COOH (R= hydrocarbon chain) Classification FA’s – Depending on the number of carbon atoms 1.Even chain: They have carbon atoms 2,4,6 and similar series. Most of the naturally occurring lipids contain even chain fatty acids. e.g. – palmitic acid(16C), stearic acid (18C) 2.Odd chain: They have carbon atoms 3, 5, 7, etc. seen in microbial cell walls. They are also present in milk. e.g. – propionic acid (3C),valeric acid (5C) FA’s – Depending on the length of carbon chain Short chain with 2 to 6 carbon atoms Medium chain with 8 to 14 carbon atoms Long chain with 16 and above, usually up to 24 carbon atoms Very long chain fatty acids (more than 24 carbon) FA’s – Depending on the nature of hydrocarbon chain 1. Saturated Fatty acids- Contain no double bonds Suffix- “anoic" 2.Unsaturated Fatty acids: Contain one or more double bonds Suffix- “enoic...

1.PHYSICAL PROPERTIES  Hy drophobic and insoluble in water 2.HYDROLYSIS OF TAG Occurs in the body during digestion of dietary fat & mobilization of fat from adipose tissue Hydrolyzed by enzymes, Pancreatic lipases Sequentially hydrolyzed to diacylglycerol and monoacylglycerol and finally glycerol plus 3 fatty acids . 3.RANCIDITY Rancidity refers to the appearance of an unpleasant smell and taste for fats and oils. Antioxidants (e.g. vitamin E) prevent the occurrence of oxidative rancidity

 SIMPLE LIPIDS •        Esters of fatty acids with alcohol 1.Waxes -   Esters of FA with long chain alcohol. Wide spread in nature Form secretions of insects, leaves & fruits of plants Not of importance in human metabolism Used as base for lubricants, cosmetics, ointments, polishes, candles 2.Fats & oils/Triacylglycerols – NEUTRAL FATS    Esters of FA with glycerol Also called as neutral fats Storage form of fat in mammals Stored in adipose tissue & function as reservoir of energy during starvation

 Definition -  Lipids are small inorganic compounds insoluble in water but soluble in non - polar solvents like chloroform,ether etc. Classification -  Functions of Lipids - Serve as Metabolic Fuels -   amount of energy obtained – 9 kcal/g Provide Cushioning effect to internal organs Form Structural component of biomembranes – Phospholipid bilayer of cell membrane Subcutaneous fat as thermal insulator Helps in formation of surfactant Improves taste of food Helps in absorption of fat soluble vitamins A,D,E,K Gives shape & contour to body Sphingomyelins – act as insulator in myelin sheath Precursor  for the synthesis of many compounds (cholesterol) - steroid hormones, bile salts,Vitamin D Lipoproteins - help in transport of Lipids

Definition: Compound lipids that contain fatty acid, glycerol, or any other alcohol, phosphoric acid residue, and the nitrogenous base is called Phospholipids. Phospholipids are amphipathic, i.e., they have both hydrophobic and hydrophilic portions in their molecule. Glycerol, Phosphoric Acid, And Choline form the hydrophilic polar head. Hydrocarbon Chains Of Fatty Acids form the hydrophobic non-polar tail. Enzymes hydrolyzing phospholipids are called phospholipases.     Classification: on the type of alcohol present, Phospholipids can be classified into two groups I.Glycerophospholipids: Glycerol is the alcohol Made of glycerol + 2 fatty acids + phosphoric acid + nitrogenous base An ester linkage links the two fatty acids to glycerol– C1 carbon contains saturated fatty acid, and C2 carbon contains unsaturated fatty acid. NITROGEN CONTAINING PHOSPHOLIPIDS a)  1. Phosphatidyl Choline (Lecithin): Made of glycerol+ fatty acids + phosphoric acid + choline(ni...

-- Normal catabolism of sphingolipids is by series of lysosomal hydrolases enzymes like 1.α and β glucosidase,  2.Galactosidase,  3.Neuraminidase,  4.Hexosaminidase & 5.Arylsulfatase --Deficiency of a single enzyme results in failure of breakdown of sphingolipids thus causing these lipid storage disorders. --Affected children are severely mentally retarded (MR) --Pre-natal diagnosis of these disorders is by amniocentesis and by culture of amniotic fluids. COMMON FEATURES OF ALL DISORDERS: --Accumulation of only one type of sphingolipid --Normal rate of synthesis of lipid but abnormal degradation of lipids -- same extent of enzyme defect in all tissues TYPES OF LIPID STORAGE DISORDERS 1.Niemann Pick's Disease -AR(autosomal recessive) -Enzyme Defect - Sphingomyelinase - Lipid accumulated - Sphingomyelin - Clinical Features - Severe CNS damage, hepatosplenomegaly, cherry rod spot in the macula Death by 2 years of age 2.Gaucher's Disease AR(autosomal recessive) -E...

DEFINITION -To become water soluble lipids get complexed with proteins to form lipoproteins -the protein part of lipoproteins is called as apolipoproteins. CLASSIFICATION depending on density of ultracentrifugation or depending on the electrophoretic mobility the lipoproteins are classified into five types 1.Chylomicrons - contain apo B-48 2.Very Low density Lipoproteins(VLDL) - contains apo-B 100 3.Intermediate density  lipoprotein 4.Low-Density Lipoprotein(LDL) -  contains apo B-100 5.High density lipoprotein(HDL) -  contain apo A STRUCTURE OF LIPOPREOTEIN -lipoproteins are made up of  --Polar Periphery - made of proteins --Polar Head - made of phospholipid & free cholesterol --Inner Core - made of hydrophobic triglycerides & tail of phospholipids FUNCTIONS OF LIPOPROTEIN Functions of Chylomicrons -Transport of dietary triglycerides from the intestine into adipose tissue from storage -Transport of dietary triglycerides form intestine ...