Class notes Biochemistry Harper's Illustrated Biochemistry Thirty-First Edition, ISBN: 9781259837944

S 01 // T 06 Albino, Alonzo, Cortes, J ustimbaste, Mislang, Tanandato, Trinidad 1 of 4 OUTLINE I. Carbohydrates are Aldehyde or Ketone Derivatives of Polyhydric Alcohols II. Biomedically, Glucose is the Most Important Monosaccharide A. Three Ways of Representing the Structure of Glucose B. Sugars Exhibit V arious Forms of Isomerism C. Many Monosaccharides are Physiologically Important D. Deoxy Sugars Lack Oxygem Atom E. Amino Sugar (Hexosamines) F. Important Disaccharides III. Polysaccharides Serve Storage & Structural Functions IV. Carbohydrates Occur in Cell Membranes & in Lipoproteins V. References OBJECTIVES  Describe the basic structure of carbohydrate s  Differentiate different types of isomerism for glucose  Describe the formation of different sugar derivatives  Enumerate the physiological important pentoses, hexoses, disacchar ides, and polysaccharides I. CARBOHYDRATES ARE ALDEHYDE OR KETONE DERIVATIVE OF POLYHYDRIC ALCOHOLS CARB OHYDRATES, SACCHARIDES & SUGAR  Carbohydrates  Compounds with empirical formula (CH 2O)n  Carbo – C, hydrate - H2O  Noong unang panahon, ang tawag ng mga scientists kasi dito ay ―hydrated carbon‖. C: carbon, H2O: water —hydrated  Empirical formula tells us whic h elements (C, H, O) are present and the simplest whole -number ratio of their atoms (kung ilan ‗yung elements doon sa molecules) General Chemistry Chang, 2010  Saccharides  Derived from the Greek sakcharon, meaning sugar Biochemistry Lehninger, 2005  Eh a ng kaso pwede pala ma -modify ang ―carbohydrates‖ —
pwede magkaroon ng amino (NH2), sulfate (SO 43-) or phosphate (PO 43-) groups  So ang saccharides – lahat ng carbohydrates [check definition sa taas] + lahat ng modified carbohydrates [carbohydrates + amino/sul fate/phosphate groups]  Sugar  Underivatized monosaccharides and small oligosaccharides such as sucrose  Sucrose ‗di ba ‗yung common sugar (pero hindi siya monosaccharide, okay? Glucose (G6) + Fructose (G6) siya) #skl#WalaSaHarpers&Lecture#HindiImbento #Ref erence:BiochemistryAppling #StrictlySpeakingLangDawYunPeroPwedePaRinNamanGamitinInterch
angeablyAngSaccharides&Carbohydrates ROLES OF CARBOHYDRATES  Energy metabolism  Molecular recognition – immune system  Cellular protection – bacterial and plant cell wa lls  Cell signaling  Cell adhesion  Biological lubrication  Control of protein trafficking  Maintenance of biological structur e CLASSIFICATION OF CARBOHYDRATES  Monosaccharides  Small, monomeric molecules  Cannot be hydrolyzed into simpler carbohydrates – simpl est carbohydrates  Typically containing from three to nine carbon atoms  Simple sugars – glucose (6 carbons, C6)  Classified as trioses (C3), tetroses (C4), pentoses (C5), hexoses (C6) or heptoses (C7)  Can be classified as aldoses or ketoses  Aldehyde  Ketone Figure 1. (From Biochemistry by Lehninger 2005) (a) L: Glyceraldehyde - R: Dihydroxyacetone Pareho silang triose (C3) pero magkaiba ng functional group na present. (b) L: Glucose – R: Fructose Pareho silang hexose (C6) pero magkaiba ulit ng functional group na present. (c) L: Ribose – R: Deoxyribose Pareho silang pentose (C5) at pareho ring aldose (aldehyde) pero ‘yung nasa right natanggalan ng -OH (hydroxyl group) sa carbon #2. Kaya siya 2 -deoxy -D-
ribose .  Disaccharide  Condensation products of two monosaccharide units  Condensation (in organic chemistry) – reaction in which two molecules combine to form a single molecule  Examples are lactose, maltose, isomaltose, sucrose, and trehalose  Oligosaccharides  Condensation products of three to ten monosaccharides  Most are not digested by human enzymes  Polysaccharides  Condensation products of more than ten monosaccharide units - long polymers of the monosaccharides II. BIOMEDICALLY, GLUCOSE IS THE MOST IMPORTANT MONOSACCHARIDE A. THREE WAYS OF REPRESENTING THE STRUCTURE OF GLUCOSE  Fischer projection or Straight -chain form – a two -dimensional representation of a three -dimensional organic molecule by projection  Haworth projection – is a common way of writing a structural formula to represent the cyclic structure of monosaccha rides with a simpl e three -dimensional perspective  Chair conformation – the most stable chemical conformation of a six-membered single bonded carbon ring such cyclohexane. CARBOHYDRATES OF PHYSIOL OGICAL SIGNIFICANCE BIOCHEMISTRY (1ST Shifting ) | (Marion G. Rivera , MD ) | (September 9, 2019 )