Chemical An er rind ' Peg Hes a THck Shur Cotton Cloth Acid Soluble pool ~ — Rdol Laoluble pook ae @simpli5yre See ae, Biomicromolecwle Riomacyomolecule € eed Dalton) (2000 Datton) Thousand of Organic Compounds 4 orga Compound +h Compounds hike Su Cs Tope, Fain ERM fie | HAPTER ju Retentate (Acid insoluble pool) Biomotecutes —> Filtrate (Acid soluble pool) 9.1 Howto Analyse There is a wide diversity in living organisms in our biosphere. Now a Chemieat question that arises in our minds is: Are all living organisms made of the Composition: same chemicals, i¢., elements and compounds? You have learnt in 9.2. Primary and. chemistry how elemental analysis is performed. If we perform such an Secondary analysis on a plant tissue, animal tissue or a microbial paste, we obtain a Metabolites: list of elements like carbon, hydrogen, oxygen and several others and 25 Pineromolcules their respective content per unit mass ofa living tissue. Ifthe same analysis Safi ane lece gees ert onn eer of een ten, we obtain a similar list. What are the differences between the two lists? In absolute terms, no such diferences could be made out.Allthe elements 9.6 Nucleic Acids present in a sample of earth's crust are also present in a sample of living 0.7 Structureof tisstie, However, a closer examination reveals that the (79 Proteins (CEGREGOREREEENEGEED with respect to other elements ishigherin any © ving organism than in earth's erust (Fable 9.11 Linking Meromers ina Polymer 9.1 How To Anatyse CuemicaL Composition? 89 Punamic Stic!" We can continue asking in the same way, what type of organic compounds Body Constituents _Weeancont king in th yy, what type of orga pound: cocoa are found in living organisms? How does one go about finding the answer? Metbolon To, Tosetan answer on has perform ache an answer, one has to perform a chemical analysis. We can (25) living tissue (a vegetable or a piece of liver, etc.) nc rine iin EChIOPORCELC 9.10 Metabolic Basis for ving © GGRICYECOOH) using a mortar and a pestle, We obtain a thick slurry. If ‘we were (0 {iSite ie EeSeSIOMOREOROAEe would obtain two 9.11 The Living State fractions, @i@ is called the (lB or more technically, (HERGRESSSIS 9.12 Enzymes (6661) and (1c(SSBHED the retentate or the acid-insoluble fraction. Scientists have found thousunds o1 @rgainie Compounds in Use Geid-SOlabIe Poo!) 94 Proteins 95 Polysaccharides 2021alanine? 0 @Simpli5yre In higher classes you will learn about how to analyse a living tissue sample and identify a webs Comparton of tment Present in eet ad iy 143 particular organic compound. It will suffice to [Ejement 9% Weight of say here that one extracts the compounds, then Earth's crust Human body subjects the extract to various separation | jiydrogen (i) O14 os techniques till one has separated a compound | Carbon (C) 0.03 185 from all other compounds. In other words, one | Oxygen (0) 48. 0. isolates and purifies a compound. Analytical Sc a oa ae techniques, when applied to the compound give | gudptim (yn) as oS us an idea of the molecular formula and the | Caleium (Ca) 36 15 probable structure of the compound @IMKB@ | Magnesium (Mg) 1 ot CHOI Silicon (Si) 7 negligible know this? A slightly different but destructive experiment has to be done. aa All the water, evaporates. (HETEnangMaCHanENESTay + Adapted from CNR Rao, Understanding Chemistry, Universities Press, Hyderabad. O.C.N,Ca.H,S.Na,Mg,Si pean a @simpli5yre Taste 9.2 A List of Representative Inorganic (GEIEH Now i the tissue is flly burnt all the Constituents of Living Tues ‘carbon compounds are oxidised to gaseous: RD (Tecdpaient as . Scum Na (HOREARIGRIEMENISTMKeTCALCLUMENMAMMESOM Potassium « (eo), Inorganic compounds like sulphate, luvs cae ‘phosphate, etc, arealso seenin theacid-soluble—_tusesuns me (GIO Mrereiore CEMENTS GES Water Ho ‘elemental composition of living tissues in the Cotspousids NaCl. CaCO, ‘form ofhydrogen, oxygen chlorine, carbon ete es ‘ii ED SASTCOMPTTAAS gives an idea of ee =o? SS Hence, Meee ST NERS toca sabato mee o are four substituent groups occupying the four valency positions. These ure hydrogen, carboxyl group, amino group and a variable group AA (GAAS) Based on the nature of R group there are many amino acids, However. those which occur (Seo Tome) ol Essextiol Non al Seal al © 2020-21144 Biowocy Aeidic Amimo ACh — G9 1: RES TTT EERE ould be «verge — (the amino acid is called (VGH) a Methyl group GIS. hydroxymethyl wudownic Acick (GHEE) etc. Three of the twenty are shown in Figure 9.1 ie A of te anINOTeARDOR aH HER MeACUONALEFOUPS. Based on number of Aspartic Gz amino and carboxyl groups, there arc ic: Tee) . a9 . CE ( (GSS) and @EENGESIA® amino acids. Similarly, there are [9 Basic amino Avid AL) (tyrosine, phenylalanine, tryptophan). A(parieular properly Histidine , Arginine, (sive ™ NEET ae 2 Neutyah Amino Acid . 7 - 4 ae Valine, Isoleucine, Leucine , aa = HiN-ch-cod} <== 1i-ch-coo EET; Alawine 2 giyene 6 ) > 2022 Aromatic: Amino Aeid(TT Fils cated xwtterionieform. 5 KGET 2022 HYomakic fine Ton ahecare ene pend Pi fatty ac ney could be Siiple fata Tytoune, prenat- ‘A atty acid has a carboxyl group attached to an R group. The ~ olowine ry tophan ape Fo ey aes b> EET ‘2021, 5 ES AED Fatty acids could be saturated, 2022. Renee (without double bond) or unsaturated (with one or more C=C double \y eet acid —donds). Another SATS SES) which oo e Here (hc team — 777" fe ‘ae EET ‘They can be ten mionoglveerides, alglyeerides GMA Cey i 2021 and triglycerides, These are| ‘and NET 1 Qwyceride +2 potty avid — @svoilliniwintérs. Can you identify a fat from the market? Some lipids 2° have POSDHOFOGS ad « CACTI 1 there 2.02 Triglyceride These arc TTT 1hey 2c TTT NET .) one example. Some tissues especially the| 2020, bags a ‘morecomplexstuctures) ~@Simpli5yre 2021 Living organisms have a number carters Compe which in which 22,24 heterocyclic rings can be found. Some of these 2 {a7 ‘2002 (EERETEMARINENEOSIN rac, anc thymine, When found attached to sugar, (hey are callcd (CESSES) | « GEESE :- also found ‘esterified to the sugar they arc called (1UGIEOMGES Adenosine, guanosine, 2003 <— Adenylic acid, thymidylic 194) <— acid, guanylic acid, uridylic acid and cytidylic acid are nucleotides. Niicleic ci DNAand RNA consist of nucleotides only: 11% @simpli5yre * cds lief DNA and RNA function as genetic material. Nitvogen base + Suger—> Nucleoside No Bose 1% MY Nitvogen base-+ Sua + Posplrate —> Nucleotide ques FawJOMOLECULES, 145 cH.0H Hoc, 00H coon coon OH eon boxy, u-e=N Ho ou CNH, H-G-NH, H-G—NH, oH OH i CH ‘CH-OF, —_ CHO, (Glucose) C,H,,0, (Ribose) eho Alanine Serine ‘amino acids Sugars (Carbohydrates) a falmitic (16) ese Se @Simpli5yre Archidonic(20) rr" 14¢ > (CH), - i CH= (CH),,—CooH GM Ecreitiel g curo-kn Fatty acid + aan (Palmitic acid) I R-C-0- ci 9 crey CHE Or Gap o-br Glycerol ‘Triglyceride (R,. R, and Ry are fatty acids) 9 toe @simpli5yre R-C-0-CH © CH-0-P-0-cH-cH, OF orig Pea Phospholipid (Lecithin) "cH Cholesterol ro 6 — Fats and oils (lipids) . Adenine A v HOCH, | S Ade SS nh HO-1 omy é a Adenine (Purine) 9 Hy? A N i Uracil (Pyrimidine) Nitrogen bases Figure Diagrammatic representation of small molecular weight organic compounds in living tissues Adenosine Aden seu146 Biowocy 9.2 Primary anp Seconpary METABOLITES ‘The most exciting aspect of chemistry deals with isolating thousands of compounds, small and big, from living organisms, determining their structure and if possible synthesising them. If one were to make a list of biomolecules, such a list would have thousands of organic compounds including amino acids, sugars, etc. For reasons that are given in section 9.10, we can call these i009 (GSES. HARASSED one notices the presence of all such categories of compounds shown ir{ EGR MeSeareealleaEngD (GABSHEES) However, when one analyses (EEAiaaaa eo Sane) one would sce thousands of compounds other than these called primary metabolites, ¢¢ alkaloids, flavonoids, rubber, essential ols, antibiotics, is coloured pigments, scents, gums, spices. These Taste 9.3 Some Secondary Metabolites are called secondary metabolites (Table 9.3) Carotenoids, Anthocyanins, While (Siiniaiiietabolitesthiaveneentiniable ete. NEET 2022,' functions and play known roles in normal Morphine, Codeine, ete.2.02}22,2° (ySIOT9Bial PFOOESSES. Montes Ogres Unde Deg a Lemon grass il te, “secondary metabolites” in host organisms. Abril Ricial NEET 202423 | However, many of them arc (29 Concanavalin A NEET 20)23 Vinblastin, curcumin, etc. (GGHEHD. Some secondary metabolites have ODS TEENS (GQISAAOAEATGED In the ater chapters and years you will learn more about this. 9.3 Bomacromorscunes @Simpli5yre ‘There is one feature common to all those compounds (ETSI (GAEDE they have molecular weights ranging from (SSD “The aeid insoluble fraction, has only four types of organic compounds Le. ‘These classes of compounds with the| have molecular weights in the For this very reason, biomolecules, i.c., chemical compounds found in living organisms are of two types, One, those which have molecular weights less than one “thousand dalton and are usually referred to as micromolecules or simply The are polymiericSubstanees, Then2ool BIOMOLECULES compounds and are present not only as such but also and (ORRIVESTEIES (CHICHETEOMWALERISOIGHIE Therefore, these membrane fragments in the form of @@SiGI@Sge0 147 use > Postion 7 Nucltc Acie) Gob > Uipiols > toe manner ‘nthe macromolecular (racton, CiSaRSmuSTseay £2 ‘The acid soluble pool represents roughly the (GHOPIASANTEGMOSILIONIThre macromolecules OM yyy. 4 average Composition of Cells ‘cytoplasm and organelles become the acid insoluble (iraction Together they represent the entire chemical Component __9 of the total eA) Cellular mass | White In summary if we represent the chemical Water a in composition of living tissue from abundance point of, teins TOSTET Painted view and arrange them class-wise, we observe that New ‘water is the most abundant chemical in living 1") "#4 S ‘organisms (Table 9.4). Hidg 2 Car Nucleic acids 57 L ant =) 1 9.4 Proreins @Simpli5yre . (PROLERISGASBONBEPUMES icy «rc linear chains of 3 shown NEET 202123 93 NEET 2022 As there ‘alanine, eysteine, na M A Taguy8 Some Proteins and their (GQEGMBEESIEES This information about the amino Protein Functions acid content is important as later in your nutrition Gottagen _ptercellular ground NEET 2020 lessons, you will learn that certain amino acids are = ‘Substance NEET 2024 essential for our health and they have tobe supplied trypsin _Enzyme NEET2024 through our dict. Hence, TTT Tsui “Hormone NEET2024 OIAANOMEIEY Therefore, aminoacids“ oii.oay “Fights infectious agents ‘can be essential oF non-essential. The latter are those Fe vertgr Sensory reception ‘which our body can make, white We get essential amin0 feccineaeaiecerest acids through our diet/food Proteins carry out many ete) functions in ving organisms, GOBEIEGEBGE® c11r-+ Enables glucose NEETDON9 (nutrients across cell membrane some fight infectious = transport yee. 202! ‘organisms, Some are hOrMONES, some are enzymes, Bois a al jactose —> Brain SugasMast Abundant Drganie 7 Comprund- giece most dloundamt Protio ‘ . ta) ete, (Table 9.5). Ribulose bisphosphate Carboxvlase-Oxygenase (RuBisCO) is the Avimal World: Coagen and Rup ‘most abundant protein(in the whole of the biosphere, Whole bingphere: RuBisCO 9.5 PovysaccHaRIDEs All —> Non Reducing ‘The acid insoluble pellet also os Sat GonaRmreasmeneneare as ‘Polysaccharides are long chains of nother class of macromolecules. Mobtrse & Gb + 0 Gly Lactose, B ola + P a ‘They are threads (literally a cotton thread) containing different Suchose © Ou + BF ny monosaccharides as building blocks. For example. polymeric polysaccharide consisting offonly one type of mortosaccharide ‘Le., glucose, CHIMOSEISANOMODONMED Starch is a variant of this but Arnytose—> 1-4 Unkeoge present asa store house of energy in plant tissues. in a SNEET Pglepettion > 1-6 Bote enttana the| Ithas bMfathesas 202° shown in tH@ form of a cartoon (Figure 9.2). S&iSHTORGSUHEHeaD ec on (CeeoRASRUCHURES, In fact, ae @simpli5yre ‘portion. The Ke end- i {t- evd- 0 Redincing. \y NEET 2023 @simpli5yre * abgecgin 7 stone Bote Ia gia OL, OO. OW. Figure 9.2 Diagrammatic representation of a portion of glycogen 6 g glucose > Aldehyde Fructose—> Ketone|| BIoMoLecuLes 149 ‘Planiticell wallsiare made oficelluilose, Paper made from plant pulp _and cotton fibre is cellulosic. Therc arc sH16re COMmplex polysaccharidgs innature. They have 2s QS amino-sugars and @hemically modified sugars (vit, glucosamine, N-acetyl galactosamine, etc.) SEED for example, have a GSDIED polysaccharide called chitin. ti ysa (NeET These complex polysaccharides are mostly voieagmamaaimes] — > NEET 2013, 20202022 9.6 Nucusc Acws (DNA €hNA) ‘The other Iype of macromolecule that one would find in the acid — Puycime_ (1992) amine, insoluble faction of any living tissue is (he TTT — (1 - lewune & the second 1s a (f0H0SEGH@HGE}nd the third a (GhOSpHOReAeIaGH Cytosine y thymine ‘phosphate, ‘As you notice in Figure 9.1, the [Hétereeyelie compounds coo. acids are th TE cc @Simplisyre (@ytosine;andthymine. Adenine and Guanine are substituted purines : while therestare substituted pyrimidines 7) SREaICEDaRENGEE —DIVA- Deoxytibose (SEAS TAMANEREEBECENEIVAN! Hc scar found in . polynucleotides is either sibosel@mmonosacchatideypentes® or 2) RNA- Ribose deoxyribose) A nucleic acid containing deoxyribose is calle (deoxyribonucleie’acid (DNA) while that which contains ribose is called ‘ribonucleic acid (RNA). 9.7. Sraucruxs or Proves @Simpli5yre (GHIEED as mentioned cartier, GETSEEROPONAES containing strings of amino acids. Structure of molecules means different things in different contexts. In inorganic chemistry, the structure invariably . refers to the molecular formulae (eg. NaCl. MgCl, ete). Organic Seeondavy: Keyakim, chemists always write a two dimensional view of the molecules while Fibvoin representing the structure of the molecules (e.g., benzene, a . naphthalene, etc.). Physicists conjure up the three dimensional views Tertiay: Myoglobin of molecular structures while hialagists describe the protein structure at four levels, The sequence of amino acids i.c., (h€|positional Quaternary (GiloeMaLION INEATGFSEEHA - which is the first amino acid, which is second, and so on ~is called the{ jof a protein. A protein is imagined as a line. NEET 2023 “the frst amino acid and the #ighitend represented bythelastiamino $k end 1 Armin Ald150 Biowocy 4 bow 0 ning 7 ORE aah \ asinptsyre he Of course, | & x of the protein thread are folded into Lat other forms in what is called the ‘secondary structure (Fig. 9.4) 111 addition, the long protein chain is also| c) ‘tertiary Peptide + H-bond ./ + Disulphide. bond giving rise to the tertiary structure (Figure 9.4 0. o Saenery ‘This gives us a 3-dimensional view of a protein. CASTS. absolutely necessary for the many) Figure 9.9 Various levels of Protein Structure a ‘Some proteins are an assembly ‘of more than one polypeptide or Subunits, The manner in which these (e.g. linear string of spheres, spheres arranged one upon each other in the form of 2p a cube or plate ete.) is the \/ ma architecture of a protein otherwise fp, Y- called the| a protein (Fig. 9.4 a), Adult human) Sub { Two of these are identical to each 'Simpli5yre 8 other. Hence, and two subunits ofB type together meme era eo psBIOMOLECULES 9.8 Narure or Bop Livxinc Monomers Iv A POLYMER 151 In a polypeptide or a protein. amino acids are linked by a peptide —> [C7 202,23 with POEL he civic! ALT AT 2014, < AASBER Ths bod is 3150 CAAT TTEEGR Ts bod 2023 (HRMUCIIEACIA » PHOSPhALEMIOIEWlinks the 3-carbon of one sugar {hiieleotide, The bond betw and (hydroxy! Broup of the! example, one of the famous Watson-Crick model. double helix. ‘run in the opposite direction. ‘The backbonelis formed by thr SHE ‘phosphate-sugar chain, the compulsorily base pairs with T and C, respectively, on the other strand. 5 8 h-God 4 o cH ‘Thymines Adenine \_ \ an oro @Simpli5yre iS) Ts v Phasprodiestey’ bond 58 o Figure 9.5. Diagram indicating secondary structure of DNA it aS 9.5). Nucleic acids exhibit a wide variety of (GSS 0S1RUGHGREED For NEET 2023 Q4=T n=c cu, S ° o-P-0 ° YeyersiicUintae se Ss o cH.152 RDNA Ome Fuk turn of Helical Strand: \0 Steps Lenath of one Full turn: SUA (34A foreach Step) Biowocy There are two hydrogen bonds between A and T «nd (FES HVEFOLEA (@GHUSWEEEIGEHEID Each strand appears like a helical staircase. Each step of ascent is represented by a pair of bases 79 One fall tum ofthe helical strand would Asenpr drawing a li dlagrars (Ghe_piteWOUa BEBAAY The rise per base pair would be 3.4A. Thus form of DNA with the above mentioned salient features iS called @® (GBD In higher classes, you will be told that there are more than a dozen forms of DNA named after English alphabets with unique structural features, 9.9 Dynamic State or Bopy Constituents — Concert oF Merasousm @Simpli5yre What we have learnt till now is that living organisms, be ita simple bacterial cell, a protozoan, a plant of an animal, contain thousands of organic compounds. These compounds or biomolecules are present in certain ‘concentrations (expressed asimols/cell ormols/litre et). One of the greatest discoveries ever made was the observation tha {Soo ESoesa@ (@EERTOVER 111i means that they are constantly being changed into some other biomolecules and also made from some other biomolecules. ‘his ‘breaking and making is through chemical reactions eonstantly occuring {in living organisms (@2U]@¢TGHaIlsUi¢SeIiehiical eae HOnSTaFETEANED ‘metabolism, |Each of the metabolic reactions results in the transformation, (GUSOMOIEEGIES) 4 few examples for such metabolic transformations are: ‘chal of sning group i nuleae be gd of gE (GenAEEALASACEHARAENELS We can list tens and thousands of such ‘examples. Majority of these metabolic reactions do not occur in isolation but are always linked to some other reactions. In other words, @GtSBSIt@3) _are converted into each other in algie ORE TeaCHOnSGAEH MetAowS ‘pathways, =" metabolic pathways are similar to the automobile trafic (GMD These pathways areeltherlinea or treular, These pathways eriss= “crosseach other, HEFEAREEMREHURGHOES, Flow of metabolites through | (iietaboLie paiva ss GERALETALEMNAGAREEHOD ce atomobite traf ‘Tismetabolite flow is called the dynamic state ofbody constituents 1: is most important is that this interlinked metabolic traffic is very smooth and without a single reported mishap for healthy conditions. Another feature of these metabolic reactions is that{ (feReHi9N 1}1-1~ |< no uncatalysed metabolic conversion in living systems.28 eo BioMoLecuLes 9.10 Metasouic Basis ror Livinc structure or 1 CS SSSSRETESTESTERD ead tose structure from a complex structure th: «1p. GIO DREOMETTCTS GD On the other han, ALAC PANTS ETAT For example ‘enengyisliberated, (1 ‘occurs in 10 metabolic steps is called glycolysis. (Living organisms have) ‘learnt fo trap this energy liberated during degradation»: storeitinte (GERPOEESTGAAED As and when needed, this bond energy is utilised, (nanan sometime wr we perform. The most important form of How do living organisms derive their energy? What strategies have they evolved? How do they store this energy and in what form? How do th convert this energy into work? You will study and understand all this under a sub-discipline called ‘Bioenergetics’ later in your higher classes, 9.11 Tue Livinc Stare At this level, you must understand that the tens and thousands of chemical compounds in a living organism, otherwise called (5000) (GEG are present at concentrations characteristic of each of them. For example, while that of OHSU (CEEIOERERASMAMIA Me most important fact of biological systems is that Gi lorie organiewe ate! 1 a. vivady-ainie charestertend ty concentrations of each ofthese biomolecules. Tes: ‘Shaul Mo Ghana peal oss moves Spon ‘to equilibrium LASTS TOES 9° shot remember {rom physics that (iia eiaao SSeS 2020-21 153 Arvobalic. —> Forwstion Metabolic pathways can eadi@ainionecompleesiictarerenaimpier Cotabbic——> BrtokDoon“ot 154 ints > Nudie ciel wslatton 9.12 Exes 9 Sa Pration nore ar Some nue acids that behave (GREERAESY These are | ‘One can depict an enzyme by a line diagram. An enzyme like Sy protein has 0 (iS). amino acid sequence of the protein. An enzyme like any protein has the (GATTI Wren you look ata tertiary structure (Figure 9.4b) you will notice that HEETERDEAEOUTE PFOCETCTCRIS “upon itself, the chain eriss-crosses itself and hence, many crevices or ‘pockets are made, Chirouigh theiractive site calalysereactionsatalhighrate Frame catalysts in many ways, but one major differen differ from inorganic catalysts i needs mention. while (GayAbOREAONE}.|owever enzymes isolated from organisms who normally 9.12.1 Chemical Reactions @Simpli5yre How do we understand these enzymes? Let us first understand a chemical reaction, Chemical compounds undergo wo ypes ofchanges, AT GEE inply fers o « ANESTSHEWAMNOMEEERLINTSE DOTS ES 10: TTS s 3 cofmatter: These are also physical processes. However, @HGHDOHGS are DEORED and ‘newbondare formed during transformation, ths wll be called a (or example: SS(aHIIOTgAHIS|CHEMIcAlTeACHOM, Similarly. hydrolysis of starch into It can be expressed as: @simpli5yre aeBiomotecutes 155 war, ror4., eS Ras OP" rt ‘When enzyme catalysed Holey te reactions are observed, the rate would be vastly higher than the same but uncatalysed reaction. For example co, See co ane nS COM carbon dioxide water carbonic acid ym times: However, b Hout 290 > 604 jowever, by using the Carbonic Anhydrase, (GHINGHEEMES Te power of enzymes is in There are thousands of types 0! (Soa STS (EEALCALGERTEEDGUGALAAG A mtistep chemical reaction, when each “ofthe steps is catalyse by the'sametenime complex or‘lierentenmes) is called 2 (SORBET For example Glucose 2 Fyruvie acid @SimpliSyre C\H,,0, + O, > 2C,H,0,+2H,0 is actually « metabolic pathway in which lueose becomes pyruvic acid hous (AATEC TATA MCLOATTAATAS V0 1 vor study respiration in Chapter 14 you will study these reactions, At this Stage you should know that this very metabolie pathway with one or two nal reactions gives rise to avariety of metabolic end produets. In 9.12.2 How do Enzymes bring about such High Rates of Chemical Conversions? To understand this we should study enzymes a little more. We have already understood the idea of an ‘active site’, The chemical or metabolic conversion refers to a reaction, (STSEniTeaiTiiiehiis convened lintOaiproduceis (GAIRARESHDSHALE) {ere enzymes, i.c. proteins with three dimensional ————— [sJ SoP It is now understood that the substrate ‘S' has to bind the enzyme at Substrate —> Product its ‘active site’ within a given cleft or pocket. The substrate has to diffuse Ets <—— £55 EP HP186 Biowocy Transition state towards the ‘active site’. There is thus, an obligatory formation of an @SURSHBIER E Activation energy stay enzyme. This @omiplex formation is without enzyme During the state where? Activation site, a new structure of the substrate called energy with enzyme AATTSAESTTCREAG's formed. Very soon, asa afler the expected bond breaking/making is completed, the product is released from the active site. In other words, the @{S=9 substrate gets transformed into the structure, GQEOANEND The pathway of this transformation must go through the so-called 4° \ Prgduct (P) transition state structure. (ToT. Bay ai Progress of reaction ‘Wanvmore altered structural states’ between fewe 9.6 Concent otacwaton cncy LLL ERE TSATED pci in this statement is the fact that all other NEET ¢ ATTESTED Sys something related to energy status of the molecule or the structure. Hence, when we look at 1% _ this pictorially through a graph it looks like something as in Figure 9.6. The y-axis represents the potential energy content. The x-axis ‘Substrate (3) tential Energy @simpli5yre repre teleengcon ape ctal eosin cation we tae Exo through the ‘transition state’. You would notice two things. ‘The energy A Ieeldiference betwen So? iD p (GED On nec not supply energy (by heating) in Endo [» order to form the product. However, 9.12.3 Nature of Enzyme Action Each enzyme (E) has a substrate (S) binding site in its molecule so that a LATS) 1s produced. This ‘complex is short-lived «nd SOCKETS PFOUREHS)PH nd unchanged enzyme with an intermediate formation of {he (25009 ‘complex (EP). ‘i formation of the ES complex is essential for catalysis. a E+S == ES ——> EP —> E+PBIOMOLECULES [The catalytic cycle of an enzyme action can be described in the following steps: 1. First, he SBSH indSTO NELEWERIEOT CERAM, Ning Into the active ate 2 1hn binging de substrate ncluces the enzyme toalter i shape, fitting more tightly around the substrate, 3. The active site of the enzyme, now in close proximity of the substrate Breaks the chemical bonds of the substrate andthe new enzyme: product complex formed. 4. The enayme releases the products of the reaction «nd QE (enayme is ready to bind to another molecule ofthe substrate and ‘run through the catalyticeyele once again. 187 Ls NEET 2024 9.12.4 Factors Affecting Enzyme Activity @Simpli5yre ‘The activity of an enzyme can be affected by a change in the conditions which can alter the tertiary structure of the protein. ther tbetute ‘temperature, pH, change in substrate concentration or binding of specific chemicals that regulate its activity. ‘Temperature and pH ‘Enzymes generally function in 2 (G22 itei Sera eaeeneE) ivigise 9.7, Each enzyme shows its highest activity ata particular (GRPEALLTE nd pH called thet ind optimum pH. GED 9 0002,,2012 Vinax co) ) s Vox 5 2 3 Pr ‘Temperature Figure 9.7 Effect of change in : (a) pH (b) Temperature and (c) Concentration of substrate on enzyme activity_ Competetive Non Competetive oo mee 158 (Uj Browocy Competitive, inhibitan, @Simpli5yre Km Valen Me concentredon of Seonate (Figure 9.7) structure and sfibitS/Whe SeGVIGHOMUETERZIME) 1 is known as (GGEESHEVENARIEEGE Duc to its close structural similarity with the Substrate, the inhibitor competes with the substrate forthe substrate- binding ate ofthe enzyme Codmgauentiy the Mgdrate cannot bind and as a result, the enzyme action declines, ¢.¢. (iTS NEET 2.024 —denvarogenase EyamalORate which closely resembles the substrate NEET 2.02 0 SiUCeinateinstruetRE Sl competiiveinibitorsareoften used inthe "control of bacterial pathogens. 9.12.5 ‘Classification and Nomenclature of Enzymes ‘Thousands of enzymes have been discovered, isolated and studied. Most of these enzymes have been classified into different groups based on the type of reactions they catalyse. “gcosidie, C-C, C-halide or P-N bonds. (BFABEB: 12.7». 191 Catalyse removal of groups from substrates by ‘mechanisms other than hydrolysis leaving double bonds, tT 6-6 x-¥+e20 20.21BioMoLecutes 159 (CORED Includes 2 Factor RB Eyes Ffpeyagne+ ft enzymes whit Pg. 700% Protien part (re 9.12.6 Co-factors @Simpli5yre 2007 Enzymes are composed of one or several poypepud chains. Hie inet ere are a number of cases in which (ioe eo Seo See. tn (GE1GEB «1 bound to the the enzyme to make the enzyme catalytically ares GEWNE In Uiese instances, (he STC PTTTTCCTTCTSCMICIMNS | GREEN Three kinds of cofactors may be identified {PROSIHEHEEFOUpS) Pagtien Neon Pasitien ‘coenzymes ne eta) 5 RRR se isingushed tong yD (face) other cofactors in that they are (iS GGRHSpOSGAmH® For comple, in SRRESERGEETEIEEE which catalyze the breakdown of ie. 2 (thelapoenzymelis only transient, usually occurring during the course of {als Fertiemor,coenames sere ascoicors in anumber of Tit Bowl 2g different enzyme catalyzed reactions. 7c are : COATES c . coenzyme CGO Post —— Coenay me (@iRCIESEAEINAD) 0 NADP}contain the vitamin niacin, ‘Anumber of enzymes require (IEIN99 for their activity which {6 fe . $ NADP coordination bonds with side chains at the active site «nc at the same Carta ase Comt en “ume form one oF more cordination bonds withthe substrate, ID Niadn ‘Summary Although there is a bewildering diversity of living organisms, their chemi composition and metabolic reactions appear to be remarkably similar. Thi elemental composition of living tissues and non-living matter appear also to be similar when analysed qualitatively. However, a closer examination reveals that the relative abundance of carbon, hydrogen and oxygen is higher in living systems when compared to inanimate matter. The most abundant chemical in living organisms is water. There are thousands of small molecular weight (<1000 Da)160 Browocy biomolecules. Amino acids, monosaccharide and disaccharide sugars, fatty acids, glycerol, nucleotides, nucleosides and nitrogen bases are some of the organic compounds seen in living organisms. There are 20 types of amino acids and 5 types of nucleotides, Fats and oils are glycerides in which fatty acids are esterified to glycerol. Phospholipids contain, in addition, a phosphorylated nitrogenous compound. Only three types of macromolecules, i.e., proteins, nucleic acids and polysaccharides are found in living systems. Lipids, because of their association with membranes separate in the macromolecular fraction. Biomacromolecules are polymers. They are made of building blocks which are different. Proteins are heteropolymers made of amino acids. Nucleic acids (RNA and DNA) are composed of nucleotides. Biomacromolecules have a hierarchy of structures - primary. secondary, tertiary and quaternary. Nucleic acids serve as genetic material. Polysaccharides are components of cell wall in plants, fungi and also of the exoskeleton of arthropods. They also are storage forms of energy (e.g... starch and glycogen), Proteins serve a variety of cellular functions. Many of them are enzymes, some are antibodies, some are receptors. are hormones and some others are structural proteins. Ci is the most abundant protein in animal world and Ribulose bisphosp! boxylas jenase (RuBisCO) is the most abundant protein in the if the biosph Enzymes are proteins which jchermigeTpRetions in the cells, Proteinaceous enzymes Ribozymes are nucleic acids wit exhibit substrate specificity, jum temperature and pH for maximal activity. They are denatured at high temperatures. Enzymes lower activation energy of reactions and enhance greatly the rate of the reactions. Nucleic acids carry hereditary information and are passed on from parental generation to progeny. EXeRcIsEs What are macromolecules? Give examples. Illustrate a glycosidic, peptide and a phospho-diester bond. What is meant by tertiary structure of proteins? Find and write down structures of 10 interesting small molecular weight biomolecules. Find ifthere is any industry which manufactures the compounds by isolation, Find out who are the buyers, 5. Proteins have primary structure. Ifyou are given a method to know which amino acid is at either of the two termini (ends) of a protein, can you connect this, information to purity or homogeneity of a protein? 6. Find out and make a list of proteins used as therapeutic agents. Find other applications of proteins (e.g.. Cosmetics etc.) PENS 7. Explain the composition of triglyceride.