Biochemistry Lecture 4 PDF

Biochemistry Fatty acids & simple lipids LECTURE (4) DR. El-Sawy 0  Biochemistry...

Biochemistry Fatty acids & simple lipids LECTURE (4) DR. El-Sawy 0  Biochemistry Fatty acids & simple lipids  Organic compounds which are : Def : Insoluble in water. Soluble in non-polar solvents as benzene, acetone.  Storage form of energy (triglycerides).  Structure of cell membranes (phospholipids & cholesterol).  Metabolic regulators (steroid hormones). ‫تنظيم و‬ ‫امتصاص‬  Absorption of fat-soluble vitamins (A, D, E & K). Importance :  Protect internal organs by providing a cushioning effect (pads of fat). ‫حماية‬  Thermal insulators (SC fat). ‫وعزل‬  Electrical insulators in neurons. Class. Compound Simple lipids Derived lipids (conjugated)  Simple and compound lipids by  Fatty acids +  Simple lipids + hydrolysis. alcohol. non-lipid part.  or substances related to lipids. DR. El-Sawy 1  Biochemistry Fatty acids & simple lipids Def  Polyhydric alcohol containing 3OH groups.  Pharmaceutical (glycerin suppositories)  Cosmetic preparations. Importance  Vasodilator agent in coronary heart dis. in form of nitro-glycerine.  Monocarboxylic straight aliphatic chains with a. Methyl group at one end (ω-carbon). Def b. Carboxyl group at other end.  The most common component of lipids in body.  Found in ester linkage in different classes of lipids. Numbering C-system Numbering start from carboxyl end. Numbering start from methyl end. a. ω-3 represent 1st double bond position at C3-C4. ω-system b. ω-6 represent 1st double bond position at C6-C7. c. ω-9 represent 1st double bond position at C9-C10. Classification According to : A) Total number of C atoms Even chain (most common) Odd chain 2, 4, 6 C. 3, 5, 7 C. DR. El-Sawy 2  Biochemistry Fatty acids & simple lipids B) Length of hydrocarbon chain Short Medium Long Very long 2 - 6 C. 8 -14 C. 16 - 22 C. ˃24 C. C) Nature of hydrocarbon chain A. Saturated fatty acids. B. Unsaturated fatty acids : Classified into : Mono-unsaturated Polyunsaturated (mono-enoic) (poly-enoic) Single double bond. 2 or more double bond. Saturated Fatty Acids : Common name No. of carbons Structure Acetic Butyric Caproic Palmitic Stearic Propionic Valeric Mono-unsaturated Fatty Acids : Common name No. of carbons Structure Palmitoleic ∆ Oleic ∆ Nervonic ∆ DR. El-Sawy 3  Biochemistry Fatty acids & simple lipids Poly-unsaturated fatty acids = PUFA = essential fatty acids : Common name No. of carbons Structure Linoleic ∆ Linolenic ∆ Arachidonic ∆  Many vegetable oils: like sunflower, olive, nuts, corn, soybean and cod liver oils. sources  Must be taken in diet because the body can't synthesize them as enzymes needed for their synthesis are absent in humans. 1. Essential for growth. 2. Essential for phospholipid formation. Importance 3. Essential for prostaglandins biosynthesis: hormone-like substances that affect several body functions, including inflammation, pain and uterine contractions. DR. El-Sawy 4  Biochemistry Fatty acids & simple lipids  Esters of fatty acids  Alcohols  may be glycerol or long chain alcohol. Def : classification Fats and oils Waxes  Esters of fatty acids with  Esters of fatty acids with long glycerol. chain monohydric alcohol. Def  Called triglycerides as they are triesters formed of glycerol & 3 fatty acids.  Simple TG: The fatty acids are 1. Beeswax: The most commonly the same e.g. palmitic or stearic known animal wax. acids forming tripalmitate or 2. Cholesterol wax: One of the Types tristearate. most important waxes in plasma  Mixed TG: Triglycerides with 3 & tissues. different fatty acids. 3. Cerumen (earwax) from ceruminous glands in ear.  Storage of energy as fat in adipose tissue "the storage form of lipid". Imp.  Provide essential fatty acids.  Carriers of fat-soluble vitamins (A-D-E-K). DR. El-Sawy 5  Biochemistry Fatty acids & simple lipids  A 38-year-old female was complaining from constipation for four days. She reported abdominal discomfort and bloating but denied weight loss or anorexia. Her physical examination was all within normal limits.  Her doctor told her to eat more vegetables and to use specific suppositories at the time of the constipation episode. Q : What is the type of suppositories?  Glycerine suppositories used in relief of constipation. DR. El-Sawy 6