PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32CarbohydratesChapter 9 (all of it)Monosaccharide (1)Oligosaccharide (2-20)Polysaccharide (>20)Representative monosaccharides, “simple sugars”single polyhydroxy aldehyde or ketone unittriosespentoses in DNA and RNAhexosesRepresentations of the two stereoisomers of glyceraldehydeD-aldosesD refers to configuration at chiral center most distance from carbonyl carbon you will be responsible for knowing the structures of the sugars named in boxes. These are the most common in nature.(Marked with )D-ketosesD-Glucose and two of its epimersTwo sugars that differ only in the configuration around one carbon atom are called epimersThe common monosaccharides have cyclic structuresFormation of two cyclic forms of D-glucosePyranoses and furanosesanomersA chair conformation of Conformations are preferred that have bulky substituents in the equatorial positionsOrganisms contain a variety of hexose derivativesR =lactic acidR-CHO=R-CO=+ H2O+ 2 H+ + 2 e-Aldehydes as reducing agentsOH1.2.3.+ O2 + H2O + H2O2R-CH=OOR-C=O-O2 + 2 H+ + 2 e- H2O2Sugars as reducing agents(Ketoses isomerize to aldoses under the conditions used for these oxidation reactions with copper ions and thus also act as reducing sugars.)Disaccharides contain an O-glycosidic BondThis ring can’t open up and is no longer reducingThis ring can open up to an aldehyde and is still reducingSome common disaccharidesStarch and Glycogen are energy storage moleculesStarch granules in chloroplastAmylose and amylopectinGlycogen granules in hepatocyteShort segment of amylose, a long, unbranched polymer of D-glucose residues in (14) linkageLike amylose, amylopectin is also high mw, but it is highly branched. Above is an (16) branch point of amylopectin.A cluster of amylose and amylopectin such as is shown above is believed to occur in starch granuoles.Glycogen is similar to amylopectin, but much more highly branched.Starch and GlycogenThe (14) linkages cause the chains in starch and glycogen to curl up and make the resulting granules very dense.Cellulose and chitin are structural homopolysaccharidesTwo units of a cellulose rigid chain. The D-glucose residues are in the (14) configuration and therefore straight.Two parallel cellulose chains, showing inter- and intrastrand hydrogen bonding cross-links between themA short segment of chitin, a homopolymer of N-actyl-D-glucosamine units in (14) linkageThe rigid component of bacterial cell walls is a heteropolymer of alternating (14) linked N-acetylglucosamine and N-acetylmuramic acid residues.The linear polymers lie side by side in the cell wall, cross-linked by short peptides, the exact structure of which depends on the bacterial species.Peptidoglycan of the cell wall of Staphylococcus aureusPeptides (strings of colored spheres) covalently link N-acetylmuramic acid residues in a neighboring polysaccharide chains.Bacterial Cell Walls Contain Peptidoglycans.only in gram-positive bacteriaRepeating units of some common glycosaminoglycans of extracellular matrix.The molecules are copolymers of alternating uronic acid and amino sugar residues, with sulfate esters in any of several positions. The ionized carboxylate and sulfate groups (red) give these polymers their characteristic negative charge.Found in synovial fluid in jointsFound in cartilage and tendonsFound in horny structuresProteoglycans: macromolecules of the cell surface or extracellular matrix in which one or more glucosaminoglycan chains are joined covalently to a membrane protein or a secreted proteinTrisaccharide linkerAct as identity tags, destination labels, mediators of specific cell-cell interactions and interactions between the cell and extracellular matrixGlycoproteins are information-rich conjugates containing oligosaccharidesBacterial lipopolysaccharides are dominant surface feature of the outer membrane of gram-negative bacteria. Space-filling model based on crystal structure of lipopolysaccharide from E. coli. (One of the fatty acid acyl chains was not visible.)Lectins, found in all organisms, are proteins that bind carbohydrates with great affinity and specificityRoles of oligosaccharides in recognition and adhesion at the cell surfacea. Oligosaccharides with unique structures, components of glycoproteins or glycolipids on the outer surface of plasma membrane,that can interact with lectins.b. Viruses that infect animal cells bind to glycoproteins on the cell as first step in infection.c. Bacterial toxins, e.g., cholera or pertussis toxins, bind to surface glycolipid before entering cells.d. Some bacteria, such as Heliobacter pylori, adhere to then colonize or infect animal cells.e. Lectins called selectin, such as those of T lymphocytes with the endothelial cells of the capillary wall at an infection site.Lectin-ligand interactions in controlling movement to the site of an infection or injury QuickTime™ and aCinepak decompressorare needed to see this picture.Lymphocytes PhagocytesMethods of Carbohydrate
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