Lec1 biochemistry copy.pdf

Biochemistry 2nd class semester 1 L1:Carbohydrates Assistant professor Ahmed Naseer Kaftan M.B.Ch.B. MSc. F.I.C.M.S Chemical pathology 1 Learning objectives: At the end of the lecture student should be able to:...

Biochemistry 2nd class semester 1 L1:Carbohydrates Assistant professor Ahmed Naseer Kaftan M.B.Ch.B. MSc. F.I.C.M.S Chemical pathology 1 Learning objectives: At the end of the lecture student should be able to: Define metabolism and its types Understand types of macromolecules and their functional groups Define carbohydrates Know the importance of carbohydrates Describe types and structure of monosaccharides Describe types and structure of disaccharides Describe types and structure of polysaccharides Email :[email protected] Website :http://Alkafeel.edu.iq 2 Learning objectives: At the end of the lecture students should be able to: Define organic chemistry Understand the importance of carbon in our life Define functional group Describe types of functional group Define the carbonyl group and describe its types Define isomer and describe its types Describe the chemical formula. Understand types of macromolecules and their functional groups Email :[email protected] Website :http://Alkafeel.edu.iq 3 Introduction  Biochemistry. Biochemistry is the branch of science that explores the chemical processes and substances that occur within living organisms,(the chemical language of life). The term Biochemistry was introduced by Carl Neuberg in 1903  Metabolism Means the series of biochemical reactions that occur for biomolecules in living organisms. Most pathways can be classified as either catabolic (degradative) or anabolic (synthetic).  Catabolic pathways break down complex molecules, such as proteins, polysaccharides, and lipids, to a few simple molecules (for example, carbon dioxide, ammonia, and water). Anabolic pathways form complex end products from simple precursors, for example, the synthesis of the polysaccharide glycogen from glucose. Stages of Metabolism  Macromolecules Macromolecules are basically polymers, long chains of molecular sub-units called monomers. Carbohydrates, proteins, and lipids are found as long polymers, they found in all living organisms, all of them are organic molecules, which means they contain carbon. They also all contain hydrogen and oxygen but in different proportions.  Draw the experiment Draw the experiment Lllll Timmy William You can talk a bit You can talk a bit about this person here about this person here  Carbohydrates The main functional groups the hydroxyl group(-OH) the carbonyl group(C=O). The bonds that are formed between carbohydrates are called glycosidic bonds. Glycosidic bondsTimmy are formed William when the hydroxyl group You canoftalkone a bit You can talk a bit carbohydrate molecule reacts about this personwith here the about this person here carbonyl group of another carbohydrate molecule.  The hydroxyl group is a polar group that can form hydrogen bonds with water molecules. This makes carbohydrates hydrophilic, or water-loving, which is important for their role as a source of energy. The carbonyl groups of carbohydrates can react with other molecules, which is important for their role in metabolism  Fatty acids Functional groups of fatty acids: Carboxyl group (-COOH):located at the end of the fatty acid chain. Methyl group (-CH3):located at the other end of the fatty acid chain. Methylene group (-CH2-): the bonds that are formed between fatty acids are called ester bonds. Ester bonds are formed when the carboxyl group of one fatty acid molecule reacts with the hydroxyl group of another fatty acid molecule.  The carboxyl group is responsible for the acidity of fatty acids. The methyl group is responsible for the hydrophobicity of fatty Timmy William acids. You can talk a bit You can talk a bit The methylene groupaboutis this person here about this person here responsible for the flexibility of fatty acids.  Amino acids Functional groups: Amino group (-NH2): Carboxyl group (-COOH): Side chain (R): The bonds that are formed between amino acids are called peptide bonds. Peptide bonds are formed when the amino group of one amino acid reacts with the carboxyl group of another amino acid. Nucleic acids Timmy William You can talk a bit You can talk a bit about this person here about this person here  Classes of enzymes 1.Oxidoreductase: Hydroxylase : add OH Oxidase: O2 as H or e Acceptor Reductase: reduction Dehydrogenase:oxidation  2.Transferase: Kinase: phosphate Carboxylase: add carboxyl -COOH 3.Hydrolase: hydrolysis of chemical bond Food digestion Timmy William 4.Lyase: cleavage of chemical bond You can talk a bit You can talk a bit Decarboxylase: remove carboxyl about this person here -COOH about this person here Aldolase 5. Isomerase Carbohydrates  Carbohydrates (saccharides) Definition: polyhydroxyalcohols with an aldehyde or keto group. They are represented with general formulae Cn(H2O)n and hence called hydrates of carbons.  Biochemical importance of Carbohydrates A. Energy production e.g. glucose. B. Formation of structural elements in animal and plant cells. C. Formation of glycolipids (carbohydrates combined with lipids) and glycoproteins (carbohydrates combined with protein).  Classification of carbohydrates: A. Monosaccharides: contain one sugar unit. B. Disaccharides: contain two sugar units. C. Oligosaccharides: contain 3 - 10 sugar units. D. Polysaccharides: contain more than 10 sugar units.  Monosaccharides: Naming (nomenclature) of monosaccharides: 1. According to the presence of aldehyde or ketone group: a) Aldoses: b) Ketoses: 2. According to the number of carbon atoms: a) Trioses: monosaccharides containing 3 carbons. b) Tetroses: monosaccharides containing 4 carbons. c) Pentoses: monosaccharides containing 5 carbons. d) Hexoses: monosaccharides containing 6 carbons.  Isomers of Monosaccharides 1. Optical isomers ( D and L-sugars ) : Asymmetric (chiral) carbon atom: is the carbon atom to which 4 different groups or atoms are attached. Any substance containing asymmetric carbon atom shows 2 Properties, Timmy William Optical activity and Optical isomerism. You can talk a bit You can talk a bit about this person here about this person here  Optical activity: It is the ability of substance to rotate either to the right or to the left. 1- If the substance rotates to light to the right so it is called: dextrorotatory or D or (+). 2- If it rotates it to the left so it is called: levorotatory or L or (-). Timmy William Glucose contains 4 You asymmetric can talk a bit carbonYou atoms. can talkIt a bitis dextrorotatory, so it is sometimes named about this person here dextrose. about this person here Most of the monosaccharides occurring in mammals are D sugars  Optical isomerism Compounds that have the same chemical formula but have different structures are called isomers. For example, fructose, glucose, mannose, and galactose are all isomers of each other, Isomers that differ Timmyin configuration around William only one specific carbonYouatom can talkare a bit definedYouascanepimers talk a bit of each. For example, glucose and galactose about this person here are C- about this person here 4 epimers.  A special type of isomerism is found in the pairs of structures that are mirror images of each other. These mirror images are called enantiomers, and the two members of the pair are designated as D- and L·sugar. Isomers obtained from Timmy the change ofWilliam position of hydroxyl group inabout ring structure, You can talk a bit this person here attached to the You can talk a bit about this person here anomeric carbon e.g. α and β glucose called anomers. Anomer & enantiomer Timmy William You can talk a bit You can talk a bit about this person here about this person here  Anomeric carbon is the carbon that attaches to two different oxygen. (C=O,C-0H) Timmy William You can talk a bit You can talk a bit about this person here about this person here  Cyclization creates a carbon with two possible orientations of the hydroxyl group around it (α-form and ß-form). In case of D-sugars, the a-form has the OH Timmygroup to the down Williamof the anomeric carbon You can talk a bit You can talk a bit and the ß- form has the OH group about about this person here to up of the this person here anomeric carbon.  Timmy William You can talk a bit You can talk a bit about this person here about this person here  Important Monosaccharides 1. Trioses: Glyceraldehyde 3-phosphate and dihydroxyacetonephosphate are intermediates during glucose oxidation in living cells. 2. Pentoses : D-ribose Timmy is a component of many William nucleosides and nucleotides and ribonucleic You can talk a bit You can talk acids a bit (RNA). - 2-deoxyribose is a component about this person here o about this person here deoxyribonucleic acid (DNA).  3. Hexoses : D-glucose ( grape sugar) is the main sugar present in blood and is present in all animal and plant cells, honey and fruits. It enters in the formation of many disaccharides and polysaccharides. It is also termed dextrose because it is dextrorotatory. – D-fructose (fruit sugar) is present in honey, Timmy William fruits and semen. It is a component of sucrose and You can talk a bit inulin. It is also You can talk a bit termed levulose because about thisit is levorotatory. person here – about this person here D-galactose is a component of lactose which is present in milk. It is also found in glycosaminoglycans (GAGS), Important Monosaccharides:  Disaccharides Disaccharides consist of two monosaccharides united together by glycosidic linkage If the glycosidic linkage involves the carbonyl group of both sugar; (e.g. sucrose) the resulting disaccharide is non-reducing. On the other hand, if theTimmy glycosidic linkage involves the William carbonyl group of oneYouofcanits talk two a bit sugarsYou (e.g. lactose can talk a bit and maltose) the resulting disaccharide isabout about this person here reducing. this person here  Timmy William You can talk a bit You can talk a bit about this person here about this person here Disaccahrides Timmy William You can talk a bit You can talk a bit about this person here about this person here  Types of disaccharides A- Reducing Disaccharides These are disaccharides which have a free anomeric carbon in the second sugar unit. Examples: Maltose, isomaltose and lactose. 1. Maltose ( Malt sugar ): It is formed of two Timmymolecules of D-glucopyranose William united by a 1,4-glucosidic You can talklinkage. a bit Maltose is athe You can talk bit main product of digestion of starch about about this person here by amylase. It is this person here hydrolyzed by maltase enzyme or by acids into two molecules of D-glucose.  Timmy William You can talk a bit You can talk a bit about this person here about this person here  2. Lactose ( Milk sugar): It is formed of ß-D- galactose and ß-D- glucose united by ß 1,4 glycosidic linkage. It is hydrolyzed by Timmy William lactase enzyme or byYou can talk a bit You can talk a bit acids into D-glucose and about this person here about this person here D-galactose.  Non -Reducing Disaccharides Sucrose (Cane sugar) ( Table sugar): It is present in plants as sugar cane and beets. It is formed of ß-D-fructose and a-D-glucose Timmy William united by a 1,2- glycosidic linkage. You can talk a bit about this person here You can talk a bit about this person here Both anomeric carbons are involved in the linkage, so sucrose is non-reducing.  Oligosaccharides These are polymers of 3-10 monosaccharide units. They are present as constituents of many types of glycolipids and glycoproteins e.g. oligosaccharides which are constituents Timmy of ABO William blood group You cansubstance, talk a bit You can talk a bit immunoglobulins, about and thisglycolipids person here about this person here and glycoproteins of cell membranes.  Polysaccharides Polysaccharides are composed of more than 10 monosaccharide units linked by glycosidic bonds. Polysaccharides are nonreducing. Polysaccharides include Timmyhomopolysaccharides William and heteropolysaccharides. You can talk a bit You can talk a bit about this person here about this person here  Homopolysaccharides These are polysaccharides which are entirely made up of only one type of monosaccharide units. They are given names according to the nature of their building units as follows: 1. Glucans: formed of D-glucose units and include starch, dextrins, glycogen Timmyand cellulose. William 2. Fructans: formed You of can D-fructose talk a bit unitsYoue.g. can inulin. talk a bit about this person here about this person here Polysaccharides Timmy William You can talk a bit You can talk a bit about this person here about this person here  Discussion ‫تخصيص وقت للنقاش التفاعلي مع الطلبة‬ 14/9/202 Email :[email protected] Website :http://Alkafeel.edu.iq 49 3 References Lippincott’s Illustrated Reviews: Biochemistry Textbook of Medical Biochemistry. M.D. Chatterjea, M. N Email :[email protected] Website :http://Alkafeel.edu.iq 50