Both cytochrome b ƒ –ƒ and plastoquinone (PQ) are oxidized by far red light and reduced by light of shorter wavelength. In light reaction,plastoquinone facilitates the transfer of electrons from : The oxygenation activity of RuBisCo enzyme in photorespiration leads to the formation of : The enzyme enterokinase helps in conversion of : Choose the correct pair from the following : (1) Exonucleases : Make cuts at specific positions within DNA. There are other forms of plastoquinone, such as ones with shorter side chains like PQ-3 (which has 3 isoprenyl side units instead of 9) as well as analogs such as PQ-B, PQ-C, and PQ-D, which differ in their side chains. 2. 2. The photosynthetic pigments absorb the sunlight. Ans_Solutions_NEET2020_(Code-F1).pdf - Test Booklet Code DATE F1 KANHA Regd Office Aakash Tower 8 Pusa Road New Delhi-110005 Ph 011-47623456 Time 3 hrs, marks. Ph. C water C plastoquinone (Pq) C plastocyanin (PC) C ATP C ferredoxin (Fd) light As plastoquinone reduces the cytochrome b6f complex, the two protons it was carrying are released into the lumen. Therefore plastoquinone facilitates the transfer of electrons from PS-II to Cyt b 6f complex. But, plastocyanin is a small water-soluble blue-copper protein that accepts a pair of electrons from the cytochrome b 6 f complex and passes it to photosystem I in the thylakoid space. The cytochrome complex, an enzyme composed of two protein complexes, transfers the electrons from the carrier molecule plastoquinone (Pq) to the protein plastocyanin (Pc), thus enabling both the transfer of protons across the thylakoid membrane and the transfer of electrons from PSII to PSI. In addition to the two electrons, Qb also picks up two protons from the stroma. Photoreaction I transfer electrons No part of the Test Booklet and Answer Sheet shall be detached under any circumstances. Light reaction II leads to the oxidation of water, thus evolving oxygen (left bottom, Fig. After excitement, e– is passed from PS-II (P 680) to primary electron acceptor … The specific palindromic sequence which is, The correct option is (3) because the specific, palindromic sequence which is recognised by. The candidates are governed by all Rules and Regulations of the examination with regard to their conduct, in the Examination Hall. It uses the energy of sunlight to transfer electrons from water to a mobile electron carrier in the membrane called plastoquinone: H 2 O → P680 → P680 * → plastoquinone. This system induces the continuous transfer of electrons through the light-absorbing molecules generally called chromophores (pigments), such as pheophytin, quinones, and chlorophyll. In addition to the two electrons, Qb also picks up two protons from the stroma. Bottom: schematic of the photosynthetic transfer chain in the thylakoid (Th) membrane of kleptoplasts in E. timida sea slugs. The reaction center chlorophyll contains electrons that can be transferred when excited. Each candidate must show on demand his/her Admission Card to the Invigilator. 17. copy number of the linked DNA in the vector. Pigments in the light-harvesting complex pass light energy to two special chlorophyll a molecules in the reaction center. Once excited, two electrons are transferred to plastoquinone Qb, the first mobile carrier. Cytochrome b6f engages in two different processes with the electrons it receives from plastoquinone: non-cyclic transport and cyclic electron transport. Do not write your Roll No. The candidates will write the Correct Test Booklet Code as given in the Test Booklet / Answer Sheet in, : Aakash Tower, 8, Pusa Road, New Delhi-110005. C) The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP. Course Hero is not sponsored or endorsed by any college or university. Light energy absorbed by the antenna complex is transferred to reaction … Each photosystem is composed of two parts. for writing particulars on this page/marking responses. It not only transfers the electrons for PS I but also is responsible for ATP production. plastoquinone. The water-splitting complex. Once excited, two electrons are transferred to plastoquinone Qb, the first mobile carrier. Photosystem II (PSII) functions to capture light energy and transfer it to plastoquinone, the first molecule in an electron transport chain that leads to the production of ATP. The steps of N.C. P.P. From primary e – acceptor, e – is passed to plastoquinone. Course Hero, Inc. The light-saturated rate of photosynthetic O2 evolution in Chlamydomonas reinhardtii declined by approximately 75% on a per-cell basis after 4 d of P starvation or 1 d of S starvation. Activation of P 700 in photosystem I enables it to pick up electrons from the cytochrome b 6 /f complex (by way of plastocyanin — PC in the figure) and raise them to a sufficiently high redox potential that, after passing through … Can you explain this answer? One photon is needed to excite each of the electrons in this chlorophyll. 1)Photo II absorbs light and energy which causes the P680 molecule to excite its e- and pass it onto an enzyme called plastoquinone. anywhere else except in the specified space in the Test. Due to the higher midpoint potential of plastoquinone in the Q A site than Pheo − the charge-separated state is stabilized, reducing the probability of a back reaction between Q A − and P680 +. Ans: In the light reaction within the chloroplast, protons in the stroma decrease in number, while in the lumen there is accumulation of protons. Try our expert-verified textbook solutions with step-by-step explanations. The electrons are transferred (by way of plastoquinone — PQ in the figure) to the cytochrome b 6 /f complex where they provide the energy for chemiosmosis. Plastoquinone (PQ) in turn, plastoquinone facilitates the transfer of, The sequence that controls the copy number, of the linked DNA in the vector, is termed, sequence is responsible for controlling the. The product(s) of reaction catalyzed by nitrogenase in root nodules of leguminous plants is/are (1) Ammonia and oxygen (2) Ammonia and hydrogen (3) Ammonia alone (4) Nitrate alone Answer (2) Sol. Q10. | EduRev NEET Question is disucussed on EduRev Study Group by 128 NEET Students. In PSII, DCMU inhibits oxygen evolution and also inhibits the reduction of cytochrome ƒ by light of shorter wavelength. Photosystem II (PSII) is a specialized protein complex that uses light energy to drive the transfer of electrons from water to plastoquinone, resulting in the production of oxygen and the release of reduced plastoquinone into the photosynthetic membrane. Photosynthetic pigments are organized into clusters called photosystems. Light of shorter wavelength (such as blue) has more energy than light of longer wavelength (such as red), so absorption of blue light creates an excited state of higher energy. - [Voiceover] In a previous video, we gave an overview of the light dependent reactions which are essentially occurring across the thyla or within or across the thylakoid membranes, right that we zoomed in on one and we saw okay we have some energy from light exciting the electrons within that chlorophyll pair, that P680 chlorophylled A pair. On completion of the test, the candidate must handover the Answer Sheet to the Invigilator before leaving, The candidates should ensure that the Answer Sheet is not folded. The reaction center chlorophyll contains electrons that can be transferred when excited. light-reactions - 4 stages primary photoevent - light photon captured by pigment, exciting the electrons in the pigment; charge separation - energy transferred to reaction center (special chlorophyll pigment) transfers energetic electron to acceptor molecule, starts electron transport This sunlight drives the process of photosynthesis. How Light-Dependent Reactions Work. 1). The cytochrome complex, an enzyme composed of two protein complexes, transfers the electrons from the carrier molecule plastoquinone (Pq) to the protein plastocyanin (Pc), thus enabling both the transfer of protons across the thylakoid membrane and the transfer of electrons from PSII to PSI. In light reaction, plastoquinone facilitates the transfer of electrons from (1) Cytb 6 f complex to PS-I (2) PS-I to NADP + (3) PS-I to ATP synthase (4) PS-II to Cytb 6 f complex Answer (4) Sol. It is composed of many molecules of chlorophyll a, chlorophyll b and carotenoids. Answer_and_Solution_NEET-2020_Code-G5(1).pdf, Delhi Technological University • POLS MISC, Ans_Solutions_NEET2020_(Code-H1)_qUFwey3.pdf, Delhi Technological University • FINANCE 101, Delhi Public School, R.K. Puram • BIOLOGY 123, Copyright © 2021. Plastoquinone (PQ) in turn transfer its e– to Cyt b 6f complex. : 011-47623456, In light reaction, plastoquinone facilitates the, plastoquinone. In light reaction I, P 700 + recovers electrons from plastocyanin, which in turn receives them from intermediate carriers, including the plastoquinone pool and cytochrome b and cytochrome f molecules. This preview shows page 1 - 3 out of 33 pages. The occurrence of two separate light reactions. The process of photosynthesis: the light reactions Light absorption and energy transfer. Antenna Complex:It is light gathering part. The overall function of light-dependent reactions, the first stage of photosynthesis, is to convert solar energy into chemical energy in the form of NADPH and ATP, which are used in light-independent reactions and fuel the assembly of sugar molecules. The ben… The reaction center of PSII (called P680) delivers its high-energy electrons, one at the time, to the primary electron … 18. 2) This creates an e- deficiency in Photo II. Plastoquinone, in turn, transfers electrons to cyt b 6 f, which feeds them into PS I. Explain how during light reaction of photosynthesis, ATP synthesis is a chemiosmotic phenomenon. N 2 + 8e– + 8H+ + 16ATP Mg 2NH 3 + H 2 + 16ADP + 16Pi Ammonia and Hydrogen. The sequence that controls the copy number of the linked DNA in the vector, is termed (1) Palindromic sequence (2) Recognition site (3) Selectable marker (4) Ori site Answer (4) Sol. The step H Rough work is to be done on the space provided for this purpose in the Test Booklet only. In light reaction, plastoquinone facilitates the transfer of electrons from (1) PS-I to NADP + (2) PS-I to ATP synthase (3) PS-II to Cytb 6 f complex (4) Cytb 6 f complex to PS-I Answer (3) Sol.   Privacy B) The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions. Find answers and explanations to over 1.2 million textbook exercises. Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students. In Photosystem I, what provides the energy necessary to transfer an electron from the P700 reaction center to the primary acceptor of PS 1?   Terms. Plastoquinone (PQ) is an isoprenoid quinone molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis. The correct option is (4) because Ori 1 answer. In light reaction, plastoquinone facilitates transfer of electrons from PS-II to C y t b 6 f complex. All cases of unfair means will be dealt with as per Rules and Regulations of this. The light excites an electron from the chlorophyll a pair, which passes to the primary electron acceptor. For each correct response, the candidate will get, will be deducted from the total scores. 1), and the transfer of electrons from the water to an intermediate pool between Photosystem II and Photosystem I (middle Fig. Facilitates the movement of electrons AND protons Passes electrons linearly to plastocyanin Passes electrons cyclically to force protons (removed from PQH2) into the lumen of the thylakoid to create a electrochemical gradient across the lumen and stroma Is ditributed evenly between PSI and II Under high light conditions, however, Q A can accept two electrons and become doubly reduced, prompting the turnover of D1 (Keren et al., 1995). One photon is needed to excite each of the electrons in this chlorophyll. In light reaction,plastoquinone facilitates the transfer of electrons from : asked Sep 14, 2020 in Biology by Manoj01 (50.1k points) neet 2020 +1 vote. The sunlight is transferred to the light-harvesting system found in the chloroplast. Following evidences could be mentioned for the existence of Z scheme: 1. Jan 07,2021 - In light reaction, plastoquinone facilitates the transfer of electrons from:a)PS-I to NADP+b)PS-I to ATP synthasec)PS-II to Cytb6f complexd)Cytb6complex to PS-ICorrect answer is option 'C'. Do not make any stray marks on the, Answer Sheet. Name the enzyme that facilitates opening of DNA helix during transcription. The key difference between plastoquinone and plastocyanin is that plastoquinone is a lipophilic carrier molecule that transfers electrons to plastocyanin through cytochrome b6f protein complex. Use of Electronic/Manual Calculator is prohibited. After excitement, e – is passed from PS-II (P 680) to primary electron acceptor (Pheophytin). No candidate, without special permission of the Superintendent or Invigilator, would leave his/her seat. After excitement, e – is passed from PS-II (P 680 ) to primary electron acceptor (Pheophytin). 16. The maximum marks are. The light energy absorbed by a chlorophyll molecule excites some electrons within the structure of the molecule to higher energy levels, or excited states. The pool of intermediate carriers may receive electrons from water via light reaction II and the quinones. The cytochrome b6f complex, an enzyme composed of two protein complexes, transfers the electrons from the carrier molecule plastoquinone (Pq) to the protein plastocyanin (Pc), ultimately facilitating the transfer of electrons from PSII to PSI. In oxygenic photosynthesis, photosystem II is the chlorophyll-containing reaction center that carries out the light-induced transfer of electrons from water to plastoquinone. These photosystems absorb and utilize the solar energy efficiently in the thylakoid membranes. The most common form of plastoquinone, known as PQ-A or PQ-9, is a 2,3-dimethyl-1,4-benzoquinone molecule with a side chain of nine isoprenylunits. 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