Module 2 - The Fundamentals of Building Blocks of Life.pdf

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1. Dr.Pravin Patil
Module 2
The Fundamentals of Building
Blocks of Life

2. oUnderstandthefundamentalbuildingblocksoflifeandtheirgoverningprinciples.
oExplorethesignificanceofmacromoleculesinlifeprocessesandtheircontributionstogrowth,
energy,andgenetics.
oInvestigatetheroleofDNAastheblueprintforlifeanditsimpactonorganismdevelopment,
function,andreproduction.
2
Objectives:

3. oAllthings,livingandnon-living,are
madeofmatter,whichoccupiesspace
andhasmass.
oMattercanexistinthreestates:solid,
liquid,andgas.
oBothlivingandnon-livingformsof
matterarecomposedofafinitesetof
chemicalelements,servingasthe
buildingblocks.
3
Introduction:
Chemical Composition of Living Forms
(Bacterial cell)

4. oElementalanalysisrevealsthepresenceof
severalelementsinbothlivingandnon-
livingmatter.
oTwenty-sixelementsarepresentinthe
humanbody;fourelements,calledthe
majorelementsconstituteabout96%ofthe
body’smassviz.oxygen,carbon,hydrogen
andnitrogen.
oEightothers,thelesserelementscontribute
to3.6%tothebody’smass.
oAnadditional14elementscalledthetrace
elementsarepresentintinyamounts.
4
Chemical Composition of Living Forms:

5. oAlllivingorganismsaremadeupofsamechemicalsthoughtheirrelativeamountsmay
bedifferent.Mostofthechemicalsinyourbodyexistintheformofcompounds.
Biologistsandchemistsdividethesecompoundsintotwoprincipalclasses:
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Chemical Composition of Living Forms:

6. 1.Organiccompounds:
Theyalwayscontaincarbonandusuallyhydrogen.Mostofthemarelargemoleculesand
manyaremadeupoflongchainsofcarbonatoms.Organiccompounds makethe
remaining38-43%ofthehumanbody.Importantcategoriesoforganiccompounds
includecarbohydrates,lipids,proteins,nucleicacidsandadenosinetriphosphate(ATP).
2.Inorganiccompounds:
Theyusuallylackcarbonandarestructurallysimple.Theirmoleculesalsohaveonlyafew
atomsandcannotbeusedbycellstoperformcomplicatedbiologicalfunctions.They
includeNa,K,Ca,Mg,waterandmanysaltsofNaClandCaCO3,acidsandbases,
compoundsofsulphateandphosphate.
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Chemical Composition of Living Forms:

7. 7
Chemical Composition of Living Forms:

8. 8
Carbohydrates:

9. Classification:
9
Carbohydrates:

10. 1.Simple/SmallCarbohydrates:
oTheycancrossplasmamembrane.Theyare,further,classifiedasfollows.
oMonosaccharides:Theyaresimplesugarsthatcontainfrom3to7carbonatoms.Eg.
glucose(themainbloodsugar),fructose(foundinfruits),galactose(foundinmilksugar)
andribose(inRNA).
oDerivedmonosaccharides:Eg.Glucuronicacid,D-glucosamine,DeoxyriboseinDNA.
oDisaccharides:Theyaresimplesugarsformedfromthecombinationoftwo
monosaccharidesbydehydrationsynthesis.
oEg.1.Sucrose(tablesugar)=glucose+fructose
o2.Lactose(milksugar)=glucose+galactose
o3.Maltose=glucose+glucose
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Carbohydrates:

11. 2.Complex/LargeCarbohydrates:
oTheycannotcrossplasmamembrane.Theyarepolysaccharidesfromtenstohundreds
ofmonosaccharidesjoinedbydehydrationsynthesis.Glycogenisthestoredformof
carbohydratesinanimals.Starchisthestoredformofcarbohydratesinplantsandmain
carbohydratesinfood.Celluloseisthepartofcellwallsinplantsthatcannotbedigested
byhumansbutaidsmovementoffoodthroughintestines.
oBasedonthecomposition,polysaccharidesareclassifiedas(i)homopolysaccharides,
containingonlyonetypeofmonosaccharides,fore.g.glycogen,starchetc.;(ii)
heteropolysaccharides,containingmorethanonetypeofmonosaccharidesortheir
derivatives,fore.g.agar,pectinetc.
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Carbohydrates:

12. 2.LargeCarbohydrates:
oBasedontheirfunction,polysaccharidesareclassifiedas(i)storagepolysaccharides
whichserveasfoodreserve,e.g.starchandglycogen;(ii)structuralpolysaccharides
whichplayroleinformationofcellwallinplants(eg.cellulose)andskeletoninanimals
(eg.chitin).
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Carbohydrates:

13. FunctionsofCarbohydrates
oGlucose,alsoknownasbloodglucose,istheprimarysource
ofenergyforthebodyandispresentinthebodyasrings.
oFructose,alsoknownaslevulose,isfoundinfoodssuchas
fruit,honey,andcornsyrup.Itentersthesmallintestine
andtravelstotheliver,whereitisprocessedbythe
glycolyticpathwaytobecomeglucose.
oLactoseisadisaccharidecomposed ofglucoseand
galactose.Itisfoundinmilkanddairyproductsandis
eitherstoredasglycogenorconvertedintoglucoseinthe
liver.
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Carbohydrates:

14. FunctionsofCarbohydrates
oRiboseisanimportantsugarfoundinvarietyof
chemicalssuchasATPbesidesbeinga
constituentofnucleotidesthatformRNA.
Similarly,deoxyribosesugarisapartof
nucleotidesthatformDNA.
oMucopolysaccharides helpinlubricationof
ligamentsandtendons,formsynovialfluid,
buildstrengthandflexibilityofskin,connective
tissuesandcartilage,bindproteinsincellwalls
andstorewaterintheinterstitialspaces.
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Carbohydrates:

15. oProteinsarevitalmacromoleculesinlivingorganisms,comprisingasignificantportion
ofacell'sstructureandaccountingforroughly12%ofitsweight.
oProteinsarecomposedofcarbon,hydrogen,oxygen,nitrogen,andsulfur,withsome
proteinscontainingadditionalelementslikephosphorus.
oProteinsaremadeupoflinearpolymerscalledpolypeptides,whichareformedby
peptidebondsbetweenaminoacids.
oAminoacidsarethemonomersthatmakeupproteins,consistingofanaminogroup,a
carboxylgroup,andasidechain.
oThereare20differentaminoacidsfoundinnature,andtheuniquesequenceofamino
acidsdeterminesthestructureandfunctionofeachprotein.
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Proteins

16. oAminoacidsarethemonomersofproteins.Eachaminoacidhasanaminogroup(-NH2),
anacidiccarboxylgroup(-COOH)andasidechain(Rgroup).
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Amino Acids:

17. oTheaminoacidsthatcanbesynthesizedbythebodyarenon-essentialaminoacids.
Thosethatcannotbesynthesizedbythebodyneedtobesupplementedinthediets.Such
aminoacidsareknownasessentialaminoacids.Fore.g.valine,leucine,histidine,lycine
etc.
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Amino Acids:

18. oShortchainsofaminoacidsarecalledpeptides.Thechainswhichhavefewerthan40or
50aminoacidsarecalledpolypeptides,whilestilllargerchainsarecalledasproteins.
Theyconsistofcarbon,hydrogen,oxygen,nitrogenelements,andsomeothersmay
containsulphur,phosphorous,ironandotherelements.
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Structure Level of Protein (Protein Folding):

19. 19
Organization (structural level):
Proteinshavefourstructurallevelsviz.,primary,secondary,tertiaryandquaternary.

20. 20
Organization (structural level):
Proteinshavefourstructurallevelsviz.,primary,secondary,tertiaryandquaternary.

21. 21
Organization (structural level):
oPrimaryStructure:Itisthesimplestlevelofprotein
structure.Thesequenceofaminoacidsinpolypeptide
chaingivestheproteininitsprimarystructure.This
sequenceisdeterminedbyDNAthroughtheprocessof
transcriptionandtranslation.
oAlthough,theprimarystructureofaproteinis
important,itdoesnotmakethefunctionalprotein.To
befunctional,proteinmusthaveaparticular3-
dimensionalconformation.Thesequenceofamino
acidsinthechaindetermineswherethechainwillbend
orfold,andwherethevariouslengthswillbeattached
toeachother.

22. 22
Organization (structural level):
SecondaryStructure:
oThepolypeptidechainsareoftencoiledorfoldedina
regularfashiontohaveasecondarystructure.
oThestructureismaintainedbyaseriesofregularly
spacedintraorintermolecularhydrogenbondsformed
betweentheaminoacidsofthesameordifferent
polypeptidechains.
oTherearetwotypesofsecondarystructureα-helix,and
β-pleatedsheets.

23. 23
Organization (structural level):
oSecondaryStructure:
oInα-helix,thepolypeptidechainiscoiledspirally,
generallyinrighthandedmanner.Atplacesthehelixis
lessregularformingrandomcoils.
oInanαhelix,thecarbonyl(C=O)ofoneaminoacidis
hydrogenbondedtotheaminoH(N-H)ofanamino
acidthatisfourdownthechain.(i.e.thecarbonylof
aminoacid1wouldformahydrogenbondtotheN-H
ofaminoacid5.)
oThisformsahelicalstructurethatresemblesacurled
ribbon,witheachturnofthehelixcontaining3.6amino
acids.

24. 24
Organization (structural level):
SecondaryStructure:
oInaβpleatedstructure,twoormoresegmentsofa
polypeptidechainlineupnexttoeachother,forminga
sheet-likestructureheldtogetherbyhydrogenbonds.
Thehydrogenbondsformbetweencarbonylandamino
groupsofbackbone.
oThestructureformsasheetinsteadofafibre.
Therefore,thissecondarystructureisoftenreferredto
aspleatedsheetorβ-pleatedsheet.
oSecondarystructureisveryimportanttoproteininthe
evolution,sizeandgeometryselectionofthesecondary
structuremotifs.

25. 25
Organization (structural level):
TertiaryStructure:
oTheoverallthree-dimensionalstructureofapolypeptideiscalled
itstertiarystructure.Thehelicalpolypeptidemoleculesfurther
coilandfoldtoassumeacomplexbutspecificstructure.
oTheproteinmoleculewillbendandtwistinsuchawayasto
achievemaximumstabilityorlowestenergystate.
oThetertiarystructureisprimarilyduetointeractionsbetweenthe
Rgroupsoftheaminoacidsthatmakeuptheprotein.Hydrogen
bonds,dipole-dipoleinteractionsandhydrophobicinteractions
producecharacteristicshapes.

26. 26
Organization (structural level):
TertiaryStructure:
oThereisonespecialtypeofcovalentbondthatcancontributeto
tertiarystructure:thedisulfidebond.Disulfidebondsarethe
covalentlinkagesbetweenthesulfur-containingsidechainsof
cysteinesandarethebondsthatcontributetotertiarystructure.
Theyactlikemolecular"safetypins,"keepingpartsofthe
polypeptidefirmlyattachedtooneanother.
oTertiarystructuregivestheproteinathreedimensional
conformation.Thebiologicalactivityofaproteinmolecule
dependslargelyonspecifictertiarystructure.

27. 27
Organization (structural level):
QuaternaryStructure:
oManyproteinsaremadeupofasinglepolypeptidechainandhave
onlythreelevelsofstructure(i.e.primary,secondaryandtertiary).
oHowever,someproteinsaremadeupofmultiplepolypeptide
chains,alsoknownassubunits.
oWhenthesesubunitscometogether,theygivetheproteinits
quaternarystructure.Largeproteinssuchashemoglobinhave
quaternarystructure.
oIthasfourchains,twoα-chainsandtwoβ-chains.

28. 28
Role/ Functions of proteins:
1.StructuralProteins:Manyproteinsserveasbuilding
materialofcellsandtissues.Theytakepartinthe
formationofcolloidalcomplexofprotoplast,cell
membranes, organelles,extracellularmatricesand
fibres.Someproteinsformsupportingstructures,e.g.,
elastinofligaments,collagenoftendons,cartilages,
boneandconnectivetissue.Keratinisthemajor
constituentofexternalprotectivestructureofanimals
likehair,feathers,hornylayerofskin,nails,claws,hoofs
etc.

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Role/ Functions of proteins:
2.Enzymes:Manyproteinsfunctionasenzymesto
catalysebiochemicalreactionsthatoccurintheliving
world.Enzymesplayakeyroleinthemetabolism.Every
enzymeisspecificinaction.E.g.,Amylase,protease,
RUBISCO etc.RUBISCO (RibuloseBisphosphate
CarboxylaseOxygenase)isthemostabundantenzyme
foundinplants.

30. 30
Role/ Functions of proteins:
3.CarrierProteins(Transportproteins):Someproteinsactascarrierswhichbindandtransport
specificmoleculesacrossamembraneorinabodyfluid.HaemoglobinofRBCstransportsoxygen
inthebody.

31. 31
Role/ Functions of proteins:
4.ReceptorProteins:Anumberofproteinspresenton
theexternalsurfaceofcellmembrane actasreceptor
molecules.Areceptorproteinmoleculereceiveschemical
signalsfromoutsideacell.Whensuchchemicalsignals
bindtoareceptor,theycausesomeformof
cellular/tissueresponse.
Forexample,wheninsulinisreleasedinblood,the
receptorproteinspresentoncellmembranebindswith
thisinsulin.Thisbindingchangesthepermeabilityofcell
membraneandglucosecanenterthecellthroughglucose
channels.

32. 32
Role/ Functions of proteins:
5.Hormones:Somehormonesareproteinaceous,e.g.,
insulin(sugarmetabolism regulatinghormone}
parathyroid(calciumandphosphatetransportregulating
hormones).Hormonesplayakeyroleintheregulationof
metabolism.

33. 33
Role/ Functions of proteins:
6.ContractileProteins:Myosinandactinmakethemusclefibrescontractileto
bringaboutmovementsandlocomotion.Thecontractilesystemisbasicallymade
upofproteinactinbutassociationwithmyosinisessentialforcontraction..
7.Defensiveproteins:Someproteinsactasantibodies(immunoglobulins)that
participateinthedefencemechanismofthebody.
8.StorageProteins:Theseoccurinmilk,eggsandseedstonourishtheyoungones.
Theyincludecaseinofmilk,albuminofeggwhiteandglutelinincereals.

34. oAnucleicacidisachainofrepeatingmonomerscalledasnucleotides.Nucleotidesare
monomericunitorbuildingblocksofnucleicacids.Eachnucleotideconsistsofthree
partsnamelynitrogenbase(e.g.adenine),afive-carbonsugar(e.g.ribose),aphosphate
group.
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Nucleic Acids:

35. oAnucleicacidisachainofrepeating
monomers calledasnucleotides.
Nucleotidesaremonomeric unitor
buildingblocksofnucleicacids.Each
nucleotideconsistsofthreepartsnamely
nitrogenbase(e.g.adenine),afive-
carbonsugar(e.g.ribose),aphosphate
group.
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Nucleic Acids:

36. oTypesofNucleicAcids
oTherearetwotypesofnucleic
acidsviz.,Deoxyribonucleicacid
(DNA) andRibonucleicacid
(RNA).
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Nucleic Acids:

37. oTypesofNucleicAcids
oDeoxyribonucleicacid(DNA):Thestructureof
DNAisgivenbytheWatson-Crickdoublehelix
model.DNAisdouble-strandedstructure.The
sugaris2’deoxyribose.Nitrogenbasespresentin
DNAareAdenine,Guanine,ThymineandCytosine.
ThetwostrandsofthedoublehelixDNAare
complementarytoeachother,andthisproperty
makesDNAsuitabletostoreandtransmitgenetic
informationfromgenerationtogeneration.
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Nucleic Acids:

38. oTypesofNucleicAcids
oRibonucleicacid(RNA):Itisasingle-stranded
structure.Itconsistsofribosesugar.Nitrogen
basespresentinRNAareAdenine,Guanine,Uracil
andCytosine.TherearethreetypesofRNAviz.,
rRNA,mRNAandtRNA.AlltheRNAsarerequired
forproteinsynthesis.
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Nucleic Acids:

39. 39
DNA vs RNA

40. oTheyarebuildingblocksofnucleicacids
(RNA,DNA).
oTheyactascarriersofchemicalenergy(ATP,
GTP).
oThey function as coenzymes for
dehydrogenasesoroxidases.
oThey are intermediaries in cellular
communications and signal transduction
40
Functions of Nucleotides:

41. oLipidsmakeup18-25%ofadultbodymass,andcontaincarbon,hydrogenandoxygen.
Theyareinsolubleinpolarsolventssuchaswater,hencehydrophobic.
41
Lipids:

42. 42
Lipids:

43. 43
Lipids:

44. oTypesofLipids:
Lipidsareclassifiedintotwomaincategories:simplelipidsandcomplexlipids.Triglycerides
areatypeofsimplelipid,whilephospholipids,waxes,andsteroidsarealltypesofcomplex
lipids.
oTriglycerides:Fatsandoils(simplelipid)
oPhospholipidsandsphingolipids(complexlipid)
oSteroids(complexlipid)
oWaxes(complexlipid)
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Lipids:

45. ClassificationofLipids
o1.Triglyceride(fatsandoils)
o2.Phospholipids:Itisamajorlipidcomponentofcellmembranes.
o3.Sphingolipids:Majorcomponentofcellmembranes
o4.Steroids:Thesearecompoundsthathavefourringsofcarbonatoms.Steroids,like
cholesterol,playrolesinreproduction,absorption,metabolismregulation,andbrain
activity.
o5.Waxes:Theyareestersoflong-chainfattyacidsandlong-chainalcohols.
45
Lipids:

46. FunctionofLipids
o1.Lipidsprovidemorethantwiceasmuchenergypergramasdocarbohydratesandproteins.
o2.Excessdietarycarbohydrates,proteins,fatsandoilsaredepositedinadiposetissuewhich
providesthermalinsulationtothebody.
o3.Usefulproductslikecookingoilcanbemanufacturedfromhydrogenationoftriglycerides,
andsoapscanbemanufacturedbysaponificationoftriglycerides.
o4.Phospholipidsandglycolipidsaremajorconstituentsofcellwallsandcellmembranes,
withphospholipidsforminglipidsbilayers.
o5.Cholesterolisanimportantsteroid,whichisknowntoactasanintermediateinthe
synthesisofothersteroidsinthehumanbody.
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Lipids:

47. FunctionofLipids
o6.Otherimportantsteroidsaresexhormones(forreproduction),vitaminD(forbone
strength),adrenocorticalhormones,bileacidsandbilesalts(fordigestionprocess)
o7.Prostaglandinsfoundinmostoftheanimaltissuesareknowntoaffectheartrate,blood
pressure,bloodclotting,fertility,whileleukotrienesregulateallergicandanti-
inflammatoryresponses.
o8.Lipoproteinsplayanimportantroleinproteinmodificationandrecognition.
o9.Waxesformprotectivecoatingsontheskin,fur,andfeathersofanimalsandonthe
leavesandfruitsofplants.
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Lipids:

48. 48