Unit 2: Carbon Assimilation

Unit-2 - Carbon Ascimliation)) ((pard-1 Introductim Carbon assimilation on blocogical Canben Fixation is the process twhich inmipnic cartoon is convented古 ongarlic compounds by Living living organisms. organisms. The complounds are then used to store energy and. others biomolecule. as stoudcturne for carbon assinication may be defined as the incorporation of carben Form atmospheric carbon dioxide into organic molecule os compound Dice glucase and othere cantond corbohydrate by living organisms. This process mainly occurs during the process of photosynthesis, containing της, Photo Synthesis by chlorophyle Howeve cacbon assimilation may occur through Chomosynthesis that takes place in the absence of schlight Example of carbon assimilation (photosynthesis): Photosynthesis is an anabolic process defined as the process in which touring organision synthesizes airbohydrates chlorophyll containing From Cay and the in the presence of antagony. The averan nexetion of photosynthesis is: high) (6+60↑ Cant to the chienphage (glucose) engern on photosynthesis the malignans mangy in to of the sunlight is being transformed bonds of en carbohytolides. chemical Energy Storrad in the Historical Boch grande See Book. Photosynthetic pigment: A photosynthetic pigment is a pigment that is present in Chionpuists of photosynthetic bacteria and captures the light energy necessary for Photosynthesis. Photo Synthetic pigments are known as light-absorbing molecule. - In photosynthesis the light energy of the Solar Radiation is absorbed by the photosynthetic pigment's which Convent the absorbed solar energy in to chemicas energy of cante hydrates. In photosynthetic organisms three major classes of piyments are fund Such as: "Ranjan kumar Sahoo A chame Carotenoide Prycobilins (1) Chlorophylls:- Plants and Chronsphyn is a pgroen Pigment, preesent in au green in cyanobacteria, which is responsible for the absorption of lights to provide energy for photosynthesis. Henre the green colour of the plant Is due to the presence plaments present in the Chiuroplasts. of chicrophyte chunsuphiyer gives plants their green colour because it does not abirib the green wavelengths of white lig light. Thal penticular light wave long is reflected from the plant, so it appeans green. Types: Dilferent fams of Chiore phyll Chlorophyll a, chi-b, Chic chi.d, Chile, Chile, bacterio Chinsophyll, Paderio viridin. chia, and chi. b, are present in higher plants and some argue where Chios ophyll a is of Universal occurrence that means chi-a is present in all photosynthetic plant, so chlia is known as Universal photo synthette pigment or primary photosynthetic pigment- Attt All other photosynthetik pigment (sive chi-b, c, d, e, fe orang polyments and phycobillins) except chi-a - on helping pigments. es are known as accessory chloro pheute, a are absent in higher plants and only present in argue anel chi e is only reported in one species of Xanthophyta Bautensio Chiamphyll and bacterio vinidin ane fund in bacteria. Chlorophyll a is the most important pigment involved Sovan chenyy by all other cheosophyn move cure & acde seong pigments in photosynthesis is tounsfersed to chia Ultimatery.. Structune: A chiosophyll molecule has two distinct components se 1) a head or porphynky ring and (in) a tail. The head is a cyeric tetrap hyreriave consisting of four hent rings jointed to one anti anarthere in ccnich one constituenti rring is The tetse pynnde nucleus. a magnesiun atom at the centre held by bond to nitrogen atoms of the 4 Pyrnole ringe in the head. ring is also present •A Fifth isocyclic ring The head is jointed to a by esterification at C7. lang hydrocarbon cham kreun os phytor tail The head is jointed hydrophille ahile the tail is hy cis phobic Therefore the head is embedded in the aqueous protein layer and the tall is directed towards the lipid bilayer in the tyllakoid in the By Riks YT Channel Charoplast Difference Between chia &chi.b:- In case of chlorophyce a the side choån on C3 of Ryanove ring I methys (CH3) group while in case of Chiorophyll & it is replaced by an aidehyde (-CHo) group. 2) In chia, and chib. of 2 hydrogen atomssing reduced by 2-the introduction 3 chiosophyll a and Chrorophile but they different b closely resemble with each other Physical and chemical properties the Chia has absorption maximal al 430 & 662 nm, while chi-bhag absorption pauks of 453 and 642 4) The solubility properties of the two pigments differ. for chia Petroleum ether is a af alcohol. good solvent and for chi-bit is methyl 5) Moleculas Formula fos chlorophyll a &b is (255 470 of Nying) (ii) carotenoids:- Carrotenoids generelly Yellow or They and ends holour are present in in all photosynthesixing cells. They and li nature and belong to the terpenoid group of compounds. Carotenoide have s 9 six membered tungt trải nghĩ choân of mychacanbms. They Jointed a lipids in highly ensatinated are again divie divided Anto a) carotenes & b) xanthophyles. (a) carotenes: These are orange pigments. Canotenes ang fimple hystrcaste hydrocarbons. The majos carotene in higher plants is which a small proportion of n lower plant photosynthetic En Carotenoid. 13-carotene with d-carotene may be present. like cugae ofene has been found. gamma (y) carotene bactoria (green) 1 E-canstone is a major "Rks YT channel" Xanthophyll - These ane yellow pigments. Xanthophine oxygen derivative of canotenes. The major sounthophylls of the They are allo the plants arce Caued canotemplis. iutein (tutor), viola xanthium (vidloxanthel) xexxanthin, Fucoxanthin (furoxanthol) and neo anthin. Among these pigments (xanthophylls) Lutein is the mest abundant. Thelxauthe phytes ane mesent in brugt higher higher prents Laugal. Morekuar Formula of lutein is (20 15602 Violaxanthin (40 456θη B-carotene (Example of carrotenes). Lutein (Example of xanthoplayer) (Structure of Commons carstenoids of higher (iii) phycobis ins Phycobirins of plants mainiy pigments of Planis ane bird group of photosynthetic mesent in blue- group grieen & warned aigae and in some other Cryptophyta. They remain attached to Protein for chich they are called phycobiliproteins of phycobilisomes. There are accessory pigments remdin attached faigare in the form of Strau bve-green in colous whis grannvies. To Chiaroplast lamellae, phycocyanin 's phyco erythrin is ried in colour. These are examples of phycobilins. By Riks YT channel. - Plycobilins ane water soluble and open-chain tetrapymnele rings unlike chiuso phyce molecure where they are closed Syrthern of Fourt Pyrmove rings. - Phyeobisins absorbs light energy For Photosynthesis and th they do not utilize it directly, rather transfer it to photochemical reaction centre of photosysters which contains chinophyll-a. Phyco Colannins occurring has main absorption in Cyanophyceae (bive-green ahile phycoerythrin Maxima at 630 nm ahile Occurring in Rhodo phyčene (ned algae) has also absorption maxima af about 500, 545 8510 nm. Robie of Photosyntes pigment Photosynthetic plament Following ane the love of Function of ghatosynthet 2 photosynthesis without photosynthetic pigments the pooren, of photosynthesis is cathinkable. The chlorophyll and other reextory with the inghe neartim of Chiosopiast. photo synthesis melecoleg ang asociated which occures in the grana of - out of different types of chlorophyce motecules, chlorophiyera is the mast Impostunt plament involved in photosynthesis. The photosynthette antenna Agment molecule trap Solar energey at different wavelengths of light and transfer to photo chemical reaction centree. Thus Photo Synthetic pigments ...I have pararicunt role in Photosynthesis. 1) photo nespiration photo synthetic pigments are also Involved in photo- respiration where cespiration orreuss time, mainly in plant In the presence of light during day but negligible in Cy nants. mitochondria and Pergeisome, Chioso plasts ane Apart From iduaved in photones piantion, Teanspiration chioso plast, present in quand segurate opening and erasing of transpirations and and of stomata alto thes megulate the rate d photo-oxidation: The arrestory photosynthetic pigments like carotenoids Pontect the chlorophyce plament against photo-oxidation (oxidati ve destruction by Solar radiation and oxygen) in green plants. Environmental Strey: Proteocyanic pigments contain defence mechanisms, like antioxidant properties, which help protect plants against environmental stresses. Stages of photo synthesis By Rke YT channel Photosynthesis in green plants takes place in two stages of phases - (i) Light reaction on photochemical reaction. Donk reaction on light independent reaction. The light reaction is photochemical which occurs only when plankare illuminated where as in dark reaction presence of light is not In light reaction chlorophyll and other pigments & the photosynthetic cen s absorbs eralighticknergy and products chyowtients of of, by photolysis Chlomplacts. conserve it int chemical formay ATP and NADPH with simultaneous of H20 Light reaction occurs in grana of the two energy In Dark recution the ATP and NADPH. Other go organic products. This reaction in the light glucose glucosecund and indipendent of light, but it is sensitive to temperature. Heaction cecurs Din' the strong of chloroplast. Dank Photo chemical Reaction photochormicas, reaction involve breaking doun of the to evolve moterular oxygen and and ATP as follows. generation of NAOPH The coater produced is the metabonic swater that is generated due to Synthesis of ATP & ip, phatochemitas reaction nivoive photo sye the tic pigments, photochemiese reexation centre antenna molecules photochemicoa rieauton photo systems and photo phosphorzyletion on light reaction disk of chieroplasts in the absorbing pigments of occurs in the thy lakoid in the presence of light. The light ty thyuakoid membrane are arranged in Fonctiende or clusters are known as photosynthesis (Ps). All the pigment molecules in photosynthetic cells absorb photons, but only one molecule (Chla) in each cluster can convert photons into chemical energy. actuary convert the light enexigy when light energy is absorbed by an excited an atom, then it crom comes t The return of the adom to its normal ground stak neults in the tes loss of the absorbed light enongy Flumescence Cells ane arr phosphorescence of heat o excited doesnot appear NADPH & ATP. by Jag O when photosynthetic light, however, the absorbed energy Fluorescence but is conventet to generak The Speciduixed energy Conventing pigment molecule consists of a Chlorophyll is Combined with a specific protein called the photochemical Realllon centre. All the Other pigment molecules in such a photo system are called Linglight rastvesting ere Antenna molecules Harinerting complexes (LHC): By RKS YT channel. Each chloroplout contains light-harvesting complexes containing Pigments like chi. a, b, xanthophifle, carotenavids, little p-caketone, and protein. All the pigments are bound to porteins. one of the Lelt functions with PS1 and the other with Ps 11. The function of Lue is to by absorbing event transferring Heaches hasp Hat energy by ancorbing Propes photo system P-76000 P680. eventually Photosystem Photosystems are functional and structural units of Protein complexes involved in photosynthesis. These are penticular pigment organization and association pto patterns chase wook is the absorption and transfer of light energy, which impllos the transfer of electrons for photosynthesis. Pia Photosystems are found in the thylakoid membranes of Plants, algae and cyanobacteria in side chicroplast. There are two kinge of photosystem de photosystore I & Photosystem I. Each granum contains about 200 nits of each PEL & PSIL 4 *A protosystem is an asserobinge of 200 to 400 pigment molecule togethe with a primary of evectron carcalers. electron acceptor and a series photo Cystom !! Potxess (PSI) aets first churcing the light transfer pati in photosynthesis, but it wees because it was discovered second. namey PS Photosystem I (PS1) photosystem I had threee kirus of pligments: Chiono phyll a (the most abundant), chlosophyes b and carotenoids. one of the Chiorophyte a molecules called Pyou because it absorbs light waves that are too nm (fare-red) and less in length is the reaction centre. of receive energy from the other pigment molecules of the System. Energy received by Pron causes electrons to move out of it and into a protein Known as Fes, so caused because it contains both. irum (Fe) and Sulphus (5) Fes, the primary electron acceptor to P700 in the thylakoid men sond photosystem I, is positioned adjacent The other electroon carriere in photosystem I, in order of decreasing Frope energy are: Ferne doxin (Fd) Flavoprofen (FAD); and nicotindemide adenin dinucleotide phosphate (NADPT) membrane The erection flow through photosystem I is there fore, as Follows: P700 Fes (1430) Fd FAD NADP+ photo system (PSE) Photosystem I consists of three kinds of pigments: chionphyte a chioso phyll b onc on d depending on the species of plants) and carotenoide. Chiosphyr is less abundant than Chlorophyll a in this photosystem. It absorbs light at slightly different wavelengths than Chlorophyll a and appears to move yellow-green than growers. The reaction center is a molecule of chlorophyll a Lecalled Psgo because it abaabs wave length that are 680nm (ned) & les. Als Chioso phyll a moleule ane Structurally Identicae, but they arme distored by adjacent proteins and consequently, absorb best Jat slightly different wavelengths. The Himary election tower acceptor of photosystem I is substanie Q(0% Unknown molecular Structure) pheophytin. - The other canniens, in onder of decreasing Plasto quinone (Pa); extract cytochrome of. Jand ane prasto cyanin (Pc). Electrom flow through photosystem II is, therefore, os Followe → Peso Phoophytin) Pqcylf Antera molecule "Rike YT channel" The anterina molecules ore antennae of the green plants consists of lange number e of of protein bound pigment moletue which absorb Photons and transfer there anengyl to the photo chemical reaction centre. of light energy is called a photon while one quantem of light energy is execitation energy transferred.. the photosystem to the next f from one molecule, to the next as in is called exciton, excitation from one pigment asin Thus in the antennae mderule is transferred ploment molecule priesent closely. to he next Structure of Antenna molecule: An antenna molecule consists of an Inner and an outer pant 1) Inner porot st is the core complex and an integral component of the neaction centre 11) spats outer porst:- This Peripheral part of the antenna is Formed of the light-harvesting complex (LHC) that engy to. the light energy and for Finere core which again neaction Centre, the exciton enengy the troansfers to the photosynthetic The mechanism by which the excitation energy of the antenna molecules ane trans Ferred to the reaction conter is extent called tresonance transfer of or forster transfer. There is a great diversity in the antenna molecules manty among aigare. In higher plants and algae, Pes and is II have unique antenna Systems that dilfer in both pigment and poroton composition and are of two groups nie the cons and the peripheral antenna complexes. the Reaction Centre The nexttion centre's the #central and mast important pigment molecule de chiorophyce which is responsible Forc the conversion ols to there accessory pigment to the cebine, Ilght enprigg into chomicas anengy pass the energy which is By Riks Vt channel. The Asapped be -St has following Feature:- Each photo system has a single routim centre.p The photochemical aut occurs at the reaction contre for which it is called as photochemical reaction centre. 3. The reaction centre only ple pass es crections to the primary electron acceptor of the photosysters and the antena maecules donot have such properity exiton eneng rzather they only to the rreaction contre. transper the energy The neaction conime in Pst contains as one chiorothya a' maecure called P700 which absorbs light waves af on less than 700 nm (-). On the other hand the recution centre in pst! ontains ane Chionophyll caused Poso chien abonks light waves of a molecule called less than 680 nm (red) 5. Energy received by Proo In Ps1 causes electrons to move aut the primary ofich and received sulphur an Piene election acceptor Proten known as Fes (Py30) oft present adjacent to 100 in the to thylakoid membrane 6. Like wise, enengy received by Piso in PSTE causes elections to move out acceptor of it and known as pheo phy tin 1680 in the thylakoid membrane. by the primary electron Present adjacent to cuaten is opt oxidized to molewiar orygon at the reaction centre of PSI, being catalyzed by the enzyme mn2t- dependent Hye dehydrogentise. & Reaction centre of PSI is the only known biological enzyme Contaring Gystem that carries out the oxidation of woetere mol de cuve to liberate molecuari oxygen, which is b majority of the organisms parth luna y respiration, including Photosynthetic For celluar organism. (Photosystern-2 reeperonting Reaction Centre and Photosynthetis Electon Transpond And Photophosphorylation prices of light-. Photosynthetic electroon dram transport describes the proven induced evectson transport hoto trophiccating. equivalents anergy and reducing chemical ener in photnsgath Phototrophic organisms. The Synthesis of ATP From ADP and inorganic phosphate in presence of light in chiamplast is known as photo phosphorylation. Photo phosphorylation was discovered by Arnon et al. There are two types of photo phosphorylation: "RKS YT channel" Non-cgesic photo phosphorylation (2-scheme) (1) Eycực photo phosphorylation: -ot is a proren of photo phosphorylation in cchich an electron expelled by the excited photo-centrre through a series of electroom carriers. to it after pussing! Geo nm onden Condition of and when (og rixatim intensity, wavelength longer than bited. Absence of Cog Fixation result in non requirement of electrimo for Fostration of NADPH Cyclic photo phospharcy caution is performed by photosystem I only. It photo- centre on reaction rentre foo extrudes an election with a gain of energy of for absorbing a photon of light (av). After lasing the electron the photo-centre becomes oxidized The expellied electron comes to its ground state on 2e where it is expelled (e Pro) through a Series of canniers incrading X on Ao (A special Proo Chinophyll molecule), A (Aquinone), Fes Complexes (fesx, FeSA, FESB), Ferredoxin (FC), Plastoquinone (PQ) Cytochrome b-f complex and plastocyanin before to photo entering returning to Centre. when evectrons pass through a series of electron canciless they recease some energy and this released energies energises pastage of Protons to create a proten gradient for synthesis of ATP (Cyclic photo phosphorylation) By Rky YT channel. (i) Non- cyclic photo phosphony eatin tis This is the normal process of photophosphorylation in which the electron expelled by the excited photo centre returns to it. Non-cyclic photo phosphorylations are carried out in collaboration with both Photosystem I (PSI) and Photol System I (PSD). Ensagy released ducing photolysis of water is picked up by photo centre of PSI O called P680. The came is extruded out when the photo centre absorbs light energy (hv) The extruded electroson hay higher energy • It pass through a series of election canniteres in order to move ground state 2re through-phaeophytin, PQ, Cytochrome. b and cytrachisam f, and plastocyanin. while parking avere cytocharme complex te in between cytochrome band f, the electron losses of FTP from ADP & Sufficient energy ganic fee phaiphate (ip). & inorganic For Synthesis Then the electron is handed over to photo centre P700015 PST by Plasdocyanin. Proo extrudes the electron af terr absorbing light energy. The extruded electron panes through special chiosphyll X, Fe-s, Ferredoxin, to reach NADPT. Finaly The NADPT lattere then combines with At (released durcing phytolysts in PSI) with the help of an enzyme, NADP-reductase to form NADPH This process is known as X-scheme due to its Characteristics Zig-Zag shape based of different electron carriers. on redox-pontential Cay Reduction ore Darck reaction": "Rus Yt channel!" In this phase, that care occurs in the stroma, cog is predvored to panbo hydrates using ATP (energy molecule) and NADPH (reducing Power) Thus dark reaction know as carbon fixing reaction. It is ta a light independent process in which Sugan O molecules are Carbondioxide and water molecules Formed from the The dane reaction utilize the in the stroινα poroducts of limeght the chloroplast, where they ATPE Dark reaction is also known as calvin cycle/scycle/Pathway- Biosynthetic phase of photosynthes's It is a cycile reaction occuring in the In this reaction, ction, Cog process of cauchon is conven Fixation dank phase of Photosynthesis. tinto sugere and hence it ista If coas first observed by melvin calvin and his collaguer in the 1950s. awarded Nobe Carvin axay an Nobel Prize Fort his work in 1961 In this cyae, 3 canben called os the first stable compaund in calvin Cycle is a Compound Cs-phosphoglyceric acid), the cycle is allo PCR (Photo syrithetic cacbon Reduction). The cawin cycle is also reeft reffered to as the reductive Pentose phosphate (RPP) cyue.