Chapter 5The Synthesis and Breakdown of PolymersSlide 3Slide 4Slide 5Slide 6Slide 7Structural Polysaccharides - CelluloseCelluloseCellulose is difficult to digestStructural Polysaccharides - ChitinSlide 12Slide 13Slide 14Phospholipid structureSlide 16SteroidsAn overview of protein functionsSlide 19Amino AcidsSlide 21Amino Acid PolymersSlide 23Four Levels of Protein StructureSecondary structureTertiary structureQuaternary structureSlide 28Slide 29DenaturationChaperoninsX-ray crystallographyDNA and Protein SynthesisSlide 34Slide 35DNA double helixSlide 37You should now be able to:Slide 39PowerPoint Lectures for Biology, Seventh EditionNeil Campbell and Jane ReeceChapter 5Chapter 5The Structure and Function of MacromoleculesThe Synthesis and Breakdown of Polymers•Monomers form larger molecules by condensation reactions called dehydration reactions(a) Dehydration reaction in the synthesis of a polymerHO H123HOHO H12 34HH2OShort polymerUnlinked monomerLonger polymerDehydration removes a watermolecule, forming a new bondFigure 5.2A•Polymers can disassemble by–Hydrolysis (b) Hydrolysis of a polymerHO123HHOH1234H2OHHOHydrolysis adds a watermolecule, breaking a bondFigure 5.2B•Examples of monosaccharidesTriose sugars(C3H6O3)Pentose sugars(C5H10O5)Hexose sugars(C6H12O6)H C OHH C OHH C OHH C OHH C OHH C OHHO C HH C OHH C OHH C OHH C OHHO C HHO C HH C OHH C OHH C OHH C OHH C OHH C OHH C OHH C OHH C OHC OC OH C OHH C OHH C OHHO C HH C OHC OHHHH H HHHH H HHHHCC C COOOOAldosesGlyceraldehydeRiboseGlucoseGalactoseDihydroxyacetoneRibuloseKetosesFructoseFigure 5.3•Monosaccharides–May be linear–Can form ringsHH C OHHO C HH C OHH C OHH COCH123456HOH4C6CH2OH 6CH2OH5CHOHCHOHH2 C1CHOHOH4C5C3 CHHOHOHH2C1 COHHCH2OHHHOHHOHOHOHH53 24(a) Linear and ring forms. Chemical equilibrium between the linear and ring structures greatly favors the formation of rings. To form the glucose ring, carbon 1 bonds to the oxygen attached to carbon 5.OH3OHOO61Figure 5.4•Examples of disaccharides Dehydration reaction in the synthesis of maltose. The bonding of two glucose units forms maltose. The glycosidic link joins the number 1 carbon of one glucose to the number 4 carbon of the second glucose. Joining the glucose monomers in a different way would result in a different disaccharide. Dehydration reaction in the synthesis of sucrose. Sucrose is a disaccharide formed from glucose and fructose.Notice that fructose,though a hexose like glucose, forms a five-sided ring.(a)(b)HHOHHOHHOHOHOHCH2OHHHOHHOHHOHOHOHCH2OHHOHHOHHOHOHOHCH2OHHH2OH2OHHOHHOHOHOHCH2OHCH2OHHOOHHCH2OHHOHHHHOOHHCH2OHHOHHOOHOHHCH2OHHOHHOHOHCH2OHHHOOCH2OHHHOHOO12141– 4glycosidiclinkage1–2glycosidiclinkageGlucoseGlucoseGlucoseFructoseMaltoseSucroseOHHHFigure 5.5Fig. 5-6(b) Glycogen: an animal polysaccharideStarchGlycogenAmyloseChloroplast(a) Starch: a plant polysaccharideAmylopectinMitochondriaGlycogen granules0.5 µm1 µmStructural Polysaccharides - CelluloseCelluloseFig. 5-8b GlucosemonomerCellulosemoleculesMicrofibrilCellulosemicrofibrilsin a plantcell wall0.5 µm10 µmCell wallsCellulose is difficult to digestStructural Polysaccharides - Chitin•Chitin, another important structural polysaccharide–Is found in the exoskeleton of arthropods and cell walls of many fungi(a) The structure of the chitin monomer. OCH2OHOHHHOHHNHCCH3OHH(b) Chitin forms the exoskeleton of arthropods. This cicada is molting, shedding its old exoskeleton and emergingin adult form. (c) Chitin is used to make a strong and flexible surgical thread that decomposes after the wound or incision heals.OHFigure 5.10 A–CFig. 5-11Fatty acid(palmitic acid)Glycerol(a) Dehydration reaction in the synthesis of a fatEster linkage(b) Fat molecule (triacylglycerol)•Saturated fatty acids–Have the maximum number of hydrogen atoms possible–Have no double bonds(a) Saturated fat and fatty acidStearic acidFigure 5.12•Unsaturated fatty acids–Have one or more double bonds(b) Unsaturated fat and fatty acidcis double bondcauses bendingOleic acidFigure 5.12Phospholipid structure•Consists of a hydrophilic “head” and hydrophobic “tails”CH2OPOOOCH2CHCH2OOCOCOPhosphateGlycerol(a) Structural formula(b) Space-filling modelFatty acids(c) Phospholipid symbolHydrophobic tailsHydrophilicheadHydrophobictails –Hydrophilic headCH2Choline+Figure 5.13 N(CH3)3Fig. 5-14HydrophilicheadHydrophobictailWATERWATERSteroidsHOCH3CH3H3CCH3CH3Cholesterol•Cholesterol, an important steroid, is a component in animal cell membranesAn overview of protein functions•Enzymes–Are a type of protein that acts as a catalyst, speeding up chemical reactionsSubstrate(sucrose) Enzyme (sucrase) GlucoseOHH OH2OFructose3 Substrate is convertedto products. 1 Active site is available for a molecule of substrate, thereactant on which the enzyme acts. Substrate binds toenzyme. 224 Products are released.Figure 5.16Amino Acids•20 different amino acids make up proteinsOO–HH3N+CCOO–HCH3H3N+CHCOO–CH3CH3CH3CCOO–HH3N+CHCH3CH2CHH3N+CH3CH3CH2CHCHH3N+CCH3CH2CH2CH3N+HCOO–CH2CH3N+HCOO–CH2NHHCOO–H3N+CCH2H2CH2NCCH2HCNonpolarGlycine (Gly)Alanine (Ala)Valine (Val) Leucine (Leu) Isoleucine (Ile)Methionine (Met)Phenylalanine (Phe)COO–Tryptophan (Trp)Proline (Pro)H3CFigure 5.17SO O–O–OHCH2CCHH3N+OO–H3N+OHCH3CHCCHO–OSHCH2CHH3N+COO–H3N+CCCH2OHHHHH3N+NH2CH2OCCCOO–NH2OCCH2CH2CCH3N+OO–OPolarElectricallycharged –O OCCH2CCH3N+HOO–O–OCCH2CCH3N+HOO–CH2CH2CH2CH2NH3+CH2CCH3N+HOO–NH2CNH2+CH2CH2CH2CCH3N+HOO–CH2NH+NHCH2CCH3N+HOO–Serine (Ser) Threonine (Thr)Cysteine (Cys)Tyrosine(Tyr)Asparagine(Asn)Glutamine(Gln)AcidicBasicAspartic acid (Asp)Glutamic acid (Glu)Lysine (Lys)Arginine (Arg)Histidine (His)Amino AcidsAmino Acid Polymers•Amino acids are linked by peptide bondsOHDESMOSOMESDESMOSOMESDESMOSOMESOHCH2CNHCHOH OH OHPeptidebondOHOHOHHHHHHHHHHHHHNNNNNSHSide chainsSHOOO OOH2OCH2CH2CH2CH2CH2CCCC C CCCCCPeptidebondAmino end(N-terminus)Backbone(a)(b) Carboxyl end(C-terminus)•Two models of protein conformation(a) A ribbon model(b) A space-filling modelGrooveGrooveFigure 5.19Four Levels of Protein Structure•Primary structure–Is the unique sequence of amino acids in a polypeptideFigure 5.20–Amino acid subunits+H3NAmino endoCarboxyl
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