IntroductiontoMacromolecules

Macromoleculesareasetofmoleculesthatarefoundinlivingorganisms.Macromoleculesessentiallymean“bigmolecules”asthewordmacromeanslarge.Thefunctionsofthesemacromoleculesplayavitalroleinmaintainingabalancedinternalenvironment.

Ifyouweretolookatthenutritionlabelofwholemilk,whatmainitemsstickout?

Youmayhavenoticedthecalories,fat,cholesterol,carbohydratesandprotein.

Threeoftheabovelisteditemsareinfactmacromolecules.

Fatandcholesterolarebothinthecategoryoflipids,andbothcarbohydratesandproteinsarebothcategoriesofmacromolecules.

Macromoleculeshave4categories

1. Carbohydrates2. Lipids3. Proteins4. NucleicAcids

Macromoleculesarebasicallyalong-chainofrepeatingstructure.Thinkofitaslego-blocksthatcanbeputtogethertomakeonelargestructure.Thesinglebuildingblocksarecalled“monomers”,whilethecombinationofmanylegoblocksarecalledpolymers.

Let’sbeginbylookingatcarbohydrates:

Carbohydratesaremadeupofsugarmolecules.Therearemanykindsofsugarmolecules.Thesugarthatweeatiscalledsucrose.Thesugarfoundinmilkislactose,andthemainsugarmoleculethatisfoundinbothanimalandplantorganismsarecalledglucose.Noticetheyallhaveanendingof–ose.

Glucosehasthebasicchemicalstructureofthefollowing:

Thereare6carbonatoms,12hydrogenatomsand6oxygenatoms.ThisgivesthebasicchemicalformulaofC6H12O6.

Thenameusedincarbohydratesiscalledsaccharide.Ifthereisjustonesaccharide(sugarmolecule),itiscalledmonosaccharide.Iftherearetwo,disaccharide,threefortrisaccharide.Anysugarthathastwoormorecouldbecalledpolysaccharide.Polysaccharideismostlyusedifthesugarmoleculesarefoundinalongerchainandisnotusedfor2sugarsconnectedtoeachother.

Whenchainsofglucoseareformedbylinkingmanyglucosemoleculestogether,wegetsomethingcalledcellulose,inplants,orglycogen,inanimals.

Celluloseprovidesthestructureforplants(suchasstems,andleaves).

Glycogenontheotherhandisfoundinanimalsandisusedasenergystorage.Animalscanbreakdownthechainsofglucosetogetindividualglucosemoleculestousethemasenergy.

Starchisanotherformofpolysaccharideswhereglucosechainsarelinkedtogether.Thedifferencebetweenglycogen,starchandcelluloseisduetohowtheglucosemoleculesarelinkedtogetherinthechemicalposition.Butatthistime,wewillfocusonthepolysaccharidesinsteadofthechemicalcomposition.Starchisfoundinplantsandisusedforenergystorage.Potatoesarerichinstarchandwhenweeatpotatoes,wearebreakingdownthestarchintosingleglucosemolecules.

Disaccharides(twosugarmoleculeslinkedtogether)

Othermorecomplicatedsugarscanbeformedbylinkingglucosemoleculestogether.

Disaccharidessuchassucrose(thesugarthatgivesthesweettaste)isformedbyconnectingaglucosemoleculewithafructose,whileamaltosesugariswhentwoglucosemoleculescombinedtogether.Lastly,lactose(thesugarthatcanmakesomepeople’sstomachupset)iswhenagalactoseandaglucoseislinkedtogether.

Disaccharidesarenotpolymersinthesensethattheydonotlinktogethertoformlargemolecules.Disaccharidesaresimplytwosugarmoleculescombinedintoonetomakeanotherformofasugar.

Usethelistonthenextpagetoseethedifferencebetweeneachofthem.

Notice how the 3 different carbohydrate polymers are made from the same glucose molecule but linked together in a different orientation

Alistofmonosaccharides,disaccharidesandpolysaccharides:

Lipids

Lipidsareessentiallyfatsofthebody.Lipidshowever,arenotconsideredasapolymer(repeatingsinglestructure).Lipidsformmanyimportantmoleculesfoundinourbodiessuchashormones,cholesterolandphospholipids.Thebasicstructureofafatmoleculehasamoleculecalledglycerolcombinedwith3fattyacidchains.Thefattyacidchainsarelongchainsofcarbonandhydrogenatomslinkedtogether.Themainfunctionoflipidisenergystorage.Otherfunctionsincludesendingsignalsaroundthebodywithhormones.

Ifyoulookatthelabelontheright,youwillnoticethatthereis“SaturatedFat”andTransfat.Basically,fatmoleculecanbebrokendowninto3types:Saturated,unsaturatedandtransfat.

Saturatedfatiswhenthefattyacidchain(thelongchain)hasjustsinglebonds(SforsaturatedandSforsinglebonds)whileunsaturatedfathasdoublebondsbetweenthecarbonatoms.Thisdoesn’tseemveryimportantbutthebondingplaysanimportantrole.Byhavingjustsinglebonds,thefatmoleculescanactuallypackmore,andformamorecondensestructure.Animalfatismadeupofsaturatedfat.Unsaturatedfathasadoublebondinthefattyacidchain,soitwillnot“pack”asclosebecauseoftheconfigurationsoyourbodycanprocessiteasier.

Transfatisanothertypeoffatanditiswhatitisclassifiedas“badfat”.Transfatisformedbyanotherdoublebondbutinanotherconfiguration.

Notice the single double bond on the fatty acid chain can cause it to become an unsaturated fat

Proteins:

Proteinsareimportantmoleculesthatmakeupatleast50%ofdrycellmass.Thefunctionsofproteinsarestructure,signaling(sendingsignals),protection(defense),carryoutchemicalreactions,transport,movement,andstorage.Proteinsaremadeupofmanysinglemoleculescalledaminoacidsthatarelinkedtogethersimilartocarbohydrates.Thereare20aminoacidsthatmakeupproteinsandtheyarelinkedtogetherby“Peptidebond”.Peptidebondisalinkagethatconnectstwoaminoacidstogetherandcanbelinkedwith1000sofotheraminoacids.

20AminoAcids

The peptide bond links the amino acid molecules together

Nucleicacids

Nucleicacidsmakeupthegeneticmaterialoflivingorganisms.Itcanmakeupdeoxyribonucleicacids(DNA),orribonucleicacids(RNA).Thebasicstructureofnucleicacidsiscomposedofsimplelinkageofnucleotides.ThenucleotideslinktogetherinlongchainsformingRNAorDNA.Individualnucleotidesareformedby3components,aribose(5carbonsugar)+nitrogenousbase+phosphatemolecule.ThevariationsofRNAandDNAcomefromthenitrogenousbasesthatformthenucleotides.Therearefourdifferentkinds,adenine(A),cytosine(C),guanine(G),andthymine(T).InorderforDNAtoformadoublehelix,hydrogenbondslinkneighboringnitrogenousbasestogether.

DNA’sdoublehelixiswhenhydrogenbondsformbetweenadjacentnitrogenousbases.

Basic nucleotide structure with a sugar base, phosphate group and a nitrogenous base

DNA is attached together by hydrogen bond between the nitrogenous bases