Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks CBSE Class-12 Chemistry Quick Revision Notes Chapter-14: Biomolecules Carbohyrates:Polyhydroxyaldehydesorpolyhydroxyketonesorcompoundsonhydrolysisgive carbohydrates.Classi!ication o! carbohyrates: Monosaccharides a)Simplest carbohydrates b)It cannot be hydrolysed into simpler compounds c)Examples - Glucose mannose !ligosaccharides a)"arbohydrates #hich gives $ to %& monosaccharide units on hydrolysis b)Examples - Sucrose 'actose Maltose Polysaccharides a)"arbohydrates #hich on hydrolysis give large number o( monosaccharide units. b)Examples - "ellulose starch "nomers:Pair o( optical isomers #hich di((er in con(iguration only around "% atom are called anomers. Examples - -)-glucopyranose and -)-glucopyranose. Epimers: Pairo(opticalisomers#hichdi((erincon(igurationaroundanyother"atomotherthan"% atom are called epimers. E.g. )-glucose and )- mannose are "$ epimers. #reparation o! $lucose %also calle e&trose' $rape su$ar(: a()rom sucrose 12 22 11 2 6 12 6 6 12 6cosHSucrose Glu e FructoseCH O HO CHO CHO++ +b()rom starch /393 ;2 312 22 5 2 6 12 6cos( )H k atmnSucrose Glu eOrCelluloseCH O HO nCHO++ Structure o! $lucose 4 2( ) CHO CHOH CHOH Structure eluciation o! $lucose: Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks a(* + $lucose ,ith -. b(* + $lucose ,ith -CN c( * + $lucose ,ith N-2/- (*- $lucose ,ith )ehlin$0s rea$ent e(* + $lucose ,ith 1ollen0s rea$ent !(* + $lucose ,ith nitric aci 4 2 4 4 2Saccharic acidacid( ) ( ) ( )Oxidtion OxidationGluconicCHO CHOH CHOH COOH CHOH COOH COOH CHOH CHOH $(* + $lucose ,ith %C-2C/(2/ an 3nCl2 3 2 25( ) /3 4 2 3 3Penta acetyl glucoseGlucose ( ) 5shows the presence of 5 -OH groupsCHCO OZnClCHO CHOCOCH CHOCOCH CH COOH + h(* + $lucose ,ith bromine ,ater 2 water4 2 4 2 acid( ) ( )BrGluconicCHO CHOH CH OH COOH CHOH CHOH i(4lucose ,ith phenyl hyra5ine to !orm osa5one Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks Glucoseand(ructosegivesthesameosa*onebecausethereactiontakesplaceat"%and "$ only. /ther Reactions o! 4lucose %#resence o! rin$ structure( GlucosedoesnotgiveSchi((+stestanddoesnotreact#ithsodiumbisulphiteand,-.. Pentaacetyl glucose does not react #ith hydroxyl amine. /his sho#s the absence o( 0"-! group and hence the presence o( ring structure. Cyclic structure o! $lucose:

-a,orth representation o! $lucose: Cyclic structure o! !ructose: Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks -a,orth representation o! !ructose 4lycosiic linka$e:/heoxidelinkage(ormedbythelosso(a#atermolecule#hent#omonosaccharidesare 1oined together through oxygen atom is called glycosidic linkage. Sucrose %invert su$ar(:a)Sucrose is a non-reducing sugar because the t#o monosaccharide units are held together byaglycosidiclinkagebet#een"%o( -glucoseand"$o( -(ructose.Sincethe reducinggroupso(glucoseand(ructoseareinvolvedinglycosidicbond(ormation sucrose is a non-reducing sugar. b)Sucroseisdextrorotatorybutonhydrolysisitgivesdextrorotatory2laevorotatoryand the mixture is laevorotatory. 0 0 012 22 11 2 6 12 6 6 12 6cos[ ] 66.5 [ ] 52.5 [ ] 92.4D D DHSucrose D glu e D fructoseCHO HO C HO C HO + =+ =+ =+ +-a,orth #ro6ection o! Sucrose: Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks 7altose: a)Maltose is composed o( t#o 3-)-glucose unitsin #hich "% o( one glucose 4I) is linked to "5 o( another glucose unit 4II).b)/he (ree aldehyde group can be produced at "% o( second glucose in solution and it sho#s reducing properties so it is a reducing sugar. 21 4Maltose Glucose+GlucoseHOC C -a,orth pro6ection o! maltose: 8actose %7ilk su$ar(: It is composed o( 6-)-galactose and 6-)-glucose. /he linkage is bet#een "% o( galactose and "5 o( glucose. -ence it is also a reducing sugar.

-a,orth pro6ection o! lactose: Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks

Starch:Itisapolymero( -glucoseandconsistso(t#ocomponents78myloseand 8mylopectin. "mylose: a)It is a #ater soluble componentb)It is a long unbranched chain polymerc)Itcontains$&&0%&&& -)-49)-glucoseunitsheldby -glycosidiclinkages involving "% 0 "5 glycosidic linkaged)It constitutes about %:-$&; o( starch"mylopectin a)It is a #ater insoluble componentb)It is branched chain polymerc)It(ormschainby"%0"5glycosidiclinkage#hereasbranchingoccursby"%0"< glycosidic linkage d)It constitutes about =&-=:; o( starchCellulose: a)It occurs exclusively in plants. b)Itisastraightchainpolysaccharidecomposedonlyo( -)-glucoseunits#hichare 1oinedbyglycosidiclinkagebet#een"%o(oneglucoseunitand"5o(thenext glucose unit. 4lyco$en: a)/he carbohydrates are stored in animal body as glycogen. b)It is also kno#n as animal starch because its structure is similar to 8mylopectin. c)It is present in liver muscles and brain. d)>hen the body needs glucose en*ymes break the glycogen do#n to glucose. "mino acis: 8mino acids contain amino 40,-$) and carboxyl 40"!!-) (unctional groups. |2NHR CH COOH >here ? 0 8ny side chain Most naturally occurring amino acids have ' 0 "on(ig. Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks

1ypes o! amino acis: a(Essential amino acis /he amino acids #hich cannot be synthesised in the body and must be obtained through diet are kno#n as essential amino acids. Examples@ Aaline 'eucine b(Non-essential amino acis /heaminoacids#hichcanbesynthesisedinthebodyarekno#nasnon-essential amino acids. Examples@ Glycine 8lanine 3,itter ion !orm o! amino acis: a)8minoacidsbehavelikesaltsratherthansimpleaminesorcarboxylicacids./his behaviour is due to the presence o( both acidic 4carboxyl group) and basic 4amino group) groupsinthesamemolecule.InaBueoussolutionthecarboxylgroupcanloseaproton andaminogroupcanacceptaprotongivingrisetoadipolarionkno#nas*#itterion. /his is neutral but contains both positive and negative charges. b)In*#itterionic(ormaminoacidssho#amphotericbehaviourastheyreactboth#ith acids and bases.

|| ||| |:(ion)2 3ZwitterO ONH NHR CH C O H R CH C O+ .soelectronic point:/he p- at #hich the dipolar ion exists as neutral ion and does not migrate to either electrode cathode or anode is called isoelectronic point.#roteins:Proteinsarethepolymerso( -aminoacidsandtheyareconnectedtoeachotherby peptide bond or peptide linkage. 8 polypeptide #ith more than hundred amino acid residues having molecular mass higher than %&&&&u is called a protein.#eptie linka$e:Peptide linkage is an amide linkage (ormed by condensation reaction bet#een 0"!!- group o( one amino acid and 0,-$ group o( another amino acid. 1||2 2 2| | | |2 1 2ROR R RHN CH COOH HN CH COOH HN CH C NH CH COOH + Peptide link age #rimary structure o! proteins:/he seBuence o( amino acids is said to be the primary structure o( a protein. Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks Seconary structure o! proteins: It re(ers to the shape in #hich long polypeptide chain can exist. /#o di((erent types o( structures@0 -elix@a)It #as given by 'inus Pauling in %C:%b)It exists #hen ?- group is large.c)?ight handed scre# #ith the ,- group o( each amino acid residue - 0 bonded to 0 " D ! o( ad1acent turn o( the helix.d)8lsokno#nas..henthepolypeptidechainsrunparallelandareheldtogetherbyhydrogenand disulphide bonds then (ibre0 like structure is (ormed.b)/hese proteins are generally insoluble in #aterc)Examples@ keratin 4present in hair #ool silk) and myosin 4present in muscles) etcGlobular proteins a)/hisstructureresults#henthechainso(polypeptidescoilaroundtogiveaspherical shape.b)/hese are usually soluble in #ater.c)Examples@ Insulin and albumins Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks Quaternary structure o! proteins: a)Some o( the proteins are composed o( t#o or more polypeptide chains re(erred to as sub-units.b)/hespatialarrangemento(thesesubunits#ithrespecttoeachotheriskno#nas Buaternary structure o( proteins.*enaturation o! proteins: a)/he loss o( biological activity o( proteins #hen a protein in its native (orm is sub1ected to physical change like change in temperature or chemical change like change in p-. /his is called denaturation o( protein.b)Example@ coagulation o( egg #hite on boiling curdling o( milk. Nucleosie: a)Hase 9 sugar Nucleotie:a)Hase 9 sugar 9 phosphate group Nucleic acis %or polynucleties(:a)'ong chain polymers o( nucleotides.b),ucleotides are 1oined by phosphodiester linkage bet#een :+ and .+ " atoms o( a pentose sugar. 1,o types o! nucleic acis: *N" a)Ithasadoublestranded -helixstructurein#hicht#ostrandsarecoiledspirallyin opposite directions.b)Sugar present is 0)0$-deoxyribosec)Hases@i) Purine bases@ 8denine 48) and Guanine 4G) ii) Pyrimidine bases@ /hymine 4/) and cytosine 4")d)It occurs mainly in the nucleus o( the cell. Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks e)It is responsible (or transmission (or heredity character.RN" a)It has a single stranded -helix structure.b)Sugar present is 0)0ribosec)Hases@i) Purine bases@ 8denine 48) and Guanine 4G)ii) Pyrimidine bases@ Iracil 4I) and cytosine 4")d)It occurs mainly in the cytoplasm o( the cell.e)It helps in protein synthesis.*ouble heli& structure o! *N": a)Itiscomposedo(t#orighthandedhelicalpolynucleotidechainscoiledspirallyin opposite directions around the same central axis.b)/#ostrandsareanti-paralleli.e.theirphosphodiesterlinkagerunsinopposite directions.c)Hases are stacked inside the helix in planesto the helical axis. d)/#o strands are held together by - 0 bonds 48 D / G "). e)/het#ostrandsarecomplementarytoeachotherbecausethehydrogenbondsare (ormed bet#een speci(ic pairs o( bases.f)8denine(ormshydrogenbonds#iththymine#hereascytosine(ormshydrogenbonds #ith guanine.g))iameter o( double helix is $ nm. h))ouble helix repeats at intervals o( ..5 nm. 4!ne complete turn) i)/otal amount o( purine 48 9 G) D /otal amount o( pyramidine 4" 9 /) :itamins:AitaminsareorganiccompoundsreBuiredinthedietinsmallamountstoper(ormspeci(ic biological (unctions (or normal maintenance o( optimum gro#th and health o( the organism.Classi!ication o! vitamins:Aitamins are classi(ied into t#o groups depending upon their solubility in #ater or (at. a)>ater soluble vitamins i) /hese vitamins are soluble in #ater.ii)>atersolublevitaminsmustbesuppliedregularlyindietbecausetheyarereadily excreted in urine and cannot be stored 4except vitamin H%$) in our body.iii) Example@ Aitamin " H group vitamins.b)Gat soluble vitamins i) /hese vitamins are soluble in (at and oils but insoluble in #ater.ii) /hey are stored in liver and adipose 4(at storing) tissues. iii) Example@ Aitamin 8 ) E and J Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks .mportant vitamins' their sources an their e!iciency iseases: Name o! vitamins Sources *e!iciency iseases Aitamin 8 Gish liver oil carrotsbutter and milkxe r o p h t h a l m i a4hardening o( cornea o(eye),ight blindnessAitamin H%4/hiamine)Keast milk greenvegetables and cerealsHeri beri 4loss o( appetiteretarded gro#th)Aitamin H$4?ibo(lavin)Milk egg #hite liverkidney"heilosis 4(issuring atcorners o( mouth andlips) digestive disordersand burning sensationo( the skin.Aitamin H