Biochemistry - Carbohydrates Lecture Notes PDF

Biochemistry Carbohydrates LECTURE (1) DR. El-Sawy 0  Biochemistry Carbohydrate...

Biochemistry Carbohydrates LECTURE (1) DR. El-Sawy 0  Biochemistry Carbohydrates  Organic compounds composed of C.H.O.  H2 and O2 are present in the proportion as in H2O. Def :  Poly-hydroxy aldehydes or poly-hydroxy ketones and all the compounds yielding them on hydrolysis. ‫ تركيب‬3‫طاقة وتعارف و‬ 1. Energy sources & fuels. 2. Cell recognition. 3. Structure of cell membranes. Function : 4. Structure of glycoproteins and glycolipids. 5. Structure of nucleic acids  pentose sugars  Ribose → RNA  Deoxy-ribose → DNA Classification : DR. El-Sawy 1  Biochemistry Carbohydrates Definition:  Carbohydrates contain only one sugar unit  Cannot be hydrolyzed into smaller units. General formula : CnH2nOn = (CH2O)n Classification: According To : 1. Number of carbon atoms. 2. The active sugar (carbonyl group) whether aldehyde or ketone. No. of carbon Generic name Aldoses Ketoses atoms 3C  Triose  Glyceraldehyde  Dihydroxyacetone 4C  Tetrose  Erythrose  Erythrulose  Arabinose 5C  Pentose  Ribose  Xylulose  Xylose  Ribulose  Glucose ‫جيجي ومني‬ 6C  Hexose  Galactose  Fructose  Mannose 7C  Heptose  Sedoheptulose Aldohexoses  The most abundant monosaccharides. Glucose  The most important & used by cells as fuel. DR. El-Sawy 2  Biochemistry Carbohydrates DR. El-Sawy 3  Biochemistry Carbohydrates DR. El-Sawy 4  Biochemistry Carbohydrates Biological Importance of Monosaccharides: Monosaccharide Functions 1) The major source of energy for humans & animal tissues. 2) Brain &RBCs depend on it as they cannot oxidize alternative fuels. Glucose (Dextrose  So, the body maintains blood glucose level 70–110 mg/dl & Grape Sugar) at all times. "Most important" 3) Ingested CHO are absorbed in form of glucose. 4) Converted into other sugars in liver & other tissues as: 1. Galactose 3. Ribose 2. Fructose 4. Glycogen 1) Synthesized in mammary gland to form lactose (Milk Galactose sugar) (disaccharides). 2) Structure of galactolipid & glycoproteins. 1) Components of glycoproteins. Mannose 2) Components of amino-sugar acids. 1) Present in semen (Seminal fluid is rich in fructose that is formed from glucose & sperms utilize fructose for energy) Fructose (Levulose 2) Enter in structure of: & Fruit Sugar) Disaccharide  sucrose. Polysaccharide  inulin 1) Form structural backbone of nucleic acids RNA & DNA. Ribose & 2) Enters in structure of: deoxy-ribose High-energy phosphate (ATP) Coenzymes such as (NAD). DR. El-Sawy 5  Biochemistry Carbohydrates Fouad is a 35 years old male patient, presented to emergency room (ER), complaints of dizziness, fatigue, pale skin, headache, sweating and rapid heartbeats. Q : What is the diagnosis ?  The case represents symptoms of hypoglycemia: 1. Dizziness 2. Fatigue 3. Pale skin 4. Headache 5. Sweating 6. Rapid heartbeats (Tachycardia).  The patient blood pressure 110/70 mmHg & random blood sugar 49 mg/dl  Some cells and tissues, including brain and erythrocytes , depend on glucose because they cannot oxidize alternative fuels.  Therefore, the body maintains a blood glucose level of 70/110 mg/dl at all times. DR. El-Sawy 6