The photosynthetic pigments absorb the sunlight. This system induces the continuous transfer of electrons through the light-absorbing molecules generally called chromophores (pigments), such as pheophytin, quinones, and chlorophyll. 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. - [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. The reaction center of PSII (called P680) delivers its high-energy electrons, one at the time, to the primary electron … 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. No candidate, without special permission of the Superintendent or Invigilator, would leave his/her seat. 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. The reaction center chlorophyll contains electrons that can be transferred when excited. 18. The water-splitting complex. The specific palindromic sequence which is, The correct option is (3) because the specific, palindromic sequence which is recognised by. 2. | EduRev NEET Question is disucussed on EduRev Study Group by 128 NEET Students. copy number of the linked DNA in the vector. 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'. Ans: In the light reaction within the chloroplast, protons in the stroma decrease in number, while in the lumen there is accumulation of protons. One photon is needed to excite each of the electrons in this chlorophyll. From primary e – acceptor, e – is passed to plastoquinone. 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. 2. Course Hero, Inc. 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. Antenna Complex:It is light gathering part. 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. The steps of N.C. P.P. The ben… 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, in turn, transfers electrons to cyt b 6 f, which feeds them into PS I. Use of Electronic/Manual Calculator is prohibited. 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. Each photosystem is composed of two parts. Light reaction II leads to the oxidation of water, thus evolving oxygen (left bottom, Fig. Once excited, two electrons are transferred to plastoquinone Qb, the first mobile carrier. 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. After excitement, e – is passed from PS-II (P 680 ) to primary electron acceptor (Pheophytin). Q10. The occurrence of two separate light reactions. 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. Fourier transform infrared spectroscopy can be used to obtain information about the structural changes that accompany electron transfer in photosystem II. 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. 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 +. In light reaction, plastoquinone facilitates the transfer of electrons from (1) Cytb 6f complex to PS-I (2) PS-I to NADP+ (3) PS-I to ATP synthase (4) PS-II to Cytb 6f complex Answer (4) Sol. The pool of intermediate carriers may receive electrons from water via light reaction II and the quinones. These photosystems absorb and utilize the solar energy efficiently in the thylakoid membranes. 1 answer. Plastoquinone (PQ) in turn transfer its e– to Cyt b 6f complex. : 011-47623456, In light reaction, plastoquinone facilitates the, plastoquinone. Plastoquinone (PQ) is an isoprenoid quinone molecule involved in the electron transport chain in the light-dependent reactions of photosynthesis. 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 … 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. 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. In oxygenic photosynthesis, photosystem II is the chlorophyll-containing reaction center that carries out the light-induced transfer of electrons from water to plastoquinone. In Photosystem I, what provides the energy necessary to transfer an electron from the P700 reaction center to the primary acceptor of PS 1? In gel electrophoresis, separated DNA fragments can be visualized with the help of . Rough work is to be done on the space provided for this purpose in the Test Booklet only. Do not make any stray marks on the, Answer Sheet. Try our expert-verified textbook solutions with step-by-step explanations. 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.   Terms. N 2 + 8e– + 8H+ + 16ATP Mg 2NH 3 + H 2 + 16ADP + 16Pi Ammonia and Hydrogen. Do not write your Roll No. Once excited, two electrons are transferred to plastoquinone Qb, the first mobile carrier. It not only transfers the electrons for PS I but also is responsible for ATP production. 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. 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 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 process of photosynthesis: the light reactions Light absorption and energy transfer. Each candidate must show on demand his/her Admission Card to the Invigilator. A photosystem consists of 1) a light-harvesting complex and 2) a reaction center. All cases of unfair means will be dealt with as per Rules and Regulations of this. After excitement, e – is passed from PS-II (P 680) to primary electron acceptor (Pheophytin). The step H The candidates are governed by all Rules and Regulations of the examination with regard to their conduct, in the Examination Hall. The correct option is (4) because Ori Course Hero is not sponsored or endorsed by any college or university. This preview shows page 1 - 3 out of 33 pages. As plastoquinone reduces the cytochrome b6f complex, the two protons it was carrying are released into the lumen. 2) This creates an e- deficiency in Photo II. Pigments in the light-harvesting complex pass light energy to two special chlorophyll a molecules in the reaction center. Photosynthetic pigments are organized into clusters called photosystems. In addition to the two electrons, Qb also picks up two protons from the stroma. The light energy absorbed by a chlorophyll molecule excites some electrons within the structure of the molecule to higher energy levels, or excited states. Explain how during light reaction of photosynthesis, ATP synthesis is a chemiosmotic phenomenon. Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. No part of the Test Booklet and Answer Sheet shall be detached under any circumstances. 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. How Light-Dependent Reactions Work. 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. After excitement, e– is passed from PS-II (P 680) to primary electron acceptor … Cytochrome b6f engages in two different processes with the electrons it receives from plastoquinone: non-cyclic transport and cyclic electron transport. Find answers and explanations to over 1.2 million textbook exercises. 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. Therefore plastoquinone facilitates the transfer of electrons from PS-II to Cyt b 6f complex. This sunlight drives the process of photosynthesis. anywhere else except in the specified space in the Test. 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. 16. In addition to the two electrons, Qb also picks up two protons from the stroma. C water C plastoquinone (Pq) C plastocyanin (PC) C ATP C ferredoxin (Fd) light 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. Photoreaction I transfer electrons Can you explain this answer? Both cytochrome b ƒ –ƒ and plastoquinone (PQ) are oxidized by far red light and reduced by light of shorter wavelength. It is composed of many molecules of chlorophyll a, chlorophyll b and carotenoids. Name the enzyme that facilitates opening of DNA helix during transcription. Ph. Under high light conditions, however, Q A can accept two electrons and become doubly reduced, prompting the turnover of D1 (Keren et al., 1995). In PSII, DCMU inhibits oxygen evolution and also inhibits the reduction of cytochrome ƒ by light of shorter wavelength. The light excites an electron from the chlorophyll a pair, which passes to the primary electron acceptor. 1)Photo II absorbs light and energy which causes the P680 molecule to excite its e- and pass it onto an enzyme called plastoquinone. 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. 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.   Privacy 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. 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. 17. 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. In light reaction, plastoquinone facilitates transfer of electrons from PS-II to C y t b 6 f complex. for writing particulars on this page/marking responses. Light energy absorbed by the antenna complex is transferred to reaction … Bottom: schematic of the photosynthetic transfer chain in the thylakoid (Th) membrane of kleptoplasts in E. timida sea slugs. 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. For each correct response, the candidate will get, will be deducted from the total scores. 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 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. The reaction center chlorophyll contains electrons that can be transferred when excited. One photon is needed to excite each of the electrons in this chlorophyll. plastoquinone. The maximum marks are. 1). 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. 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