Molecules of Life: BiomoleculesStructural HierarchyCARBOHYDRATESMonosaccharides Vary in StructureSlide 5Slide 6Slide 7The Structure of Di/Polysaccharides ; Glycosidic LinkagesDISACCHARIDESSlide 10Types of PolysaccharidesSlide 12Slide 13Representative PolysaccharidesSlide 15How Do Carbohydrates Provide Structure?Slide 17What Are the Chemical Structures and Functions of Carbohydrates?Glycoproteins: Cell IdentitySlide 20Slide 21Key ConceptsHow Do Carbohydrates Store Energy?Carbohydrates and Energy StorageEnergy Stored in Glucose Is Transferred to ATPSlide 26Slide 27© 2011 Pearson Education, Inc.Molecules of Life: Biomolecules√Proteins: Building blocks of proteins are the amino acids (C, H, O, N) (monomer = amino acid)example: enzymes catalyzing biochemical reactions, antibodies protecting against diseases… √Nucleic acids: RNA, DNA (C, H,O, P, N) Storing/ transferring genetic information (monomer = nucleotide)Carbohydrates: Monosaccharides & derivatives (C, H, O) Cn(H2O)n (monomer = monosaccharide)example: Starch, cellulose…(phosphorylated / sulphated sugars)lipids: Fatty acids, Cholesterol (C,H,[O]) membrane components (phosphorylated lipids)© 2011 Pearson Education, Inc.Structural HierarchyKnowledge of Knowledge of the chemical the chemical structure of structure of bio moleculesbio molecules and their and their biological biological functionfunction is very is very important in important in understanding understanding biological biological processesprocesses within the cell.within the cell.© 2011 Pearson Education, Inc.CARBOHYDRATES•General Formula for simple sugar = Cn(H2O)n Monosaccharides (monomer)•Water soluble, sweet-tasting carbohydrates  sugars-Major end product of the photosynthetic incorporation of inorganic C (CO2) into living matter. Carbohydrates play MANY important roles:•(1) Major Energy Source (ex: glycogen)•(2) Cell-cell interactions and immune recognition•(3) Polysaccharides are essential structural components in plants, ex. Cellulose (Glu)n•Definition: Poly hydroxy aldehydes (Aldoses) orPoly hydroxy ketones (Ketoses)Carbonyl functional group found in all carbohydrates© 2011 Pearson Education, Inc.Monosaccharides Vary in Structure•Monosaccharide monomers are simple sugars that structurally vary in four primary ways:1. Location of the carbonyl group–Aldose: found at the end of the monosaccharide–Ketose: found in the middle of the monosaccharide2. Number of carbon atoms present–Triose: three–Pentose: five–Hexose: six3. Spatial arrangement of their atoms–Different arrangement of the hydroxyl groups 4. Linear and alternative ring forms–Sugars tend to form ring structures in aqueous solutions.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Anomeric carbon and Muta rotation:Muta-Rotation: Spontaneous conversion of Muta-Rotation: Spontaneous conversion of άά  ββ© 2011 Pearson Education, Inc.Each monosaccharide has a unique structure and function.Many distinct monosaccharides exist because so many aspects of their structure are variable: - aldose or ketose placement of the carbonyl group-variation in carbon number- different arrangements of hydroxyl groups in space-alternative ring forms.© 2011 Pearson Education, Inc.The Structure of Di/Polysaccharides ; Glycosidic Linkages•Polysaccharides, or complex carbohydrates, are polymers of monosaccharide monomers.•The simplest polysaccharides are disaccharides, comprised of two monosaccharide monomers.–The monomers can be identical or different.Simple sugars polymerize when a condensation reaction occurs between two hydroxyl groups, resulting in a covalent bond called a glycosidic linkage.•The glycosidic linkages can form between two hydroxyl groups; thus, the location and geometry of these bonds vary widely.© 2011 Pearson Education, Inc.DISACCHARIDES•Two monosaccharides linked together by a glycosidic bond. C1 of one of the sugars is involved.•4 important disaccharides:1. Sucrose = glucose + fructose  common table sugar extracted from sugar cane and sugar beets,  (12) linkage between the two anomeric C2. Lactose = galactose + glucose  milk sugar (14) glucosidic linkage3. Maltose = glu + glu  hydrolysis of starch (14) linkage4. Cellobiose = glu + glu = hydrolysis of cellulose (14) linkage•Mammals can not digest this linkage due to the lack of the enzyme.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Types of Polysaccharides1. Plants store sugar as starch.–Mixture of branched (amylopectin) and unbranched (amylose) -glucose polymer2. Animals store sugar as glycogen.–Highly branched -glucose polymer3. Cellulose is a structural polymer found in plant cell walls.–Polymer of -glucose monomers4. Chitin is a structural polymer found in fungi cell walls, some algae, and many animal exoskeletons.–Comprised of N-acetylglucosamine (NAc) monomers5. Bacterial cell walls get structural support from peptidoglycan.–Backbones of alternating monosaccharides© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc. Representative Polysaccharides Macromolecular structureLinear (cellulose)Highly branched (glycogen)Branched (starch)Parallel cellulose molecules form hydrogen bonds, resulting in thin fibrils.The high amount of branching glycogen makes its solid deposits more compact than starch.Branching limits the number of hydrogen bonds that can form in starch molecules, making starch less compact than cellulose.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.How Do Carbohydrates Provide Structure?•Cellulose, chitin, and peptidoglycan form long strands with bonds between adjacent strands.  parallel strands, NOT branched•These strands may then be organized into fibers or layered in sheets to give cells and organisms great strength and elasticity.•Unlike the α-glycosidic linkages in the storage polysaccharides, the β-1,4-glycosidic linkages of structural carbohydrates are very difficult to hydrolyze very few enzymes have active sites that accommodate their geometry or have the reactive groups necessary.© 2011 Pearson Education, Inc.•Proteins  peptide bonds•Nucleic acids  phosphodiester bonds•Polysaccharides  glycosidic bonds•All covalent bonds!!© 2011 Pearson Education, Inc.What Are the Chemical Structures and Functions of Carbohydrates?Oligosaccharides may