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A researcher wanted to study light reaction during photosynthesis by blocking photosynthetic electron flow using the herbicide, di-chloro-phenyl-dimethyl-urea (DCMU) and paraquat. The researcher listed the following observations: A. Both DCMU […]

44. The one of the most widely used herbicides methyl viologens (paraquat) interfere photosynthesis of higher plants. They are responsible for (1) Evolution of more oxygen (2) Dissipation of proton […]

43. Identify the correct site of action of DBMIB (2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone), an inhibitor of the chloroplast electron transport chain. (1)QA —àQB                (2) QB —àPQ’ (3) PQ —àCytb6 f         (4) […]

42. The herbicide, dichlorophenyldi-methylurea (DCMU), is an inhibitor of (1) Shikimate pathway for biosynthesis of aromatic amino acids. (2) Electron transport from P680 to P700. (3) Branch in amino acid […]

41. Dichlorophenyl dimethyl urea       (DCMU) inhibits photosynthesis at which step? (1) phe–àQA                          (2) QA–àQB (3) Cyt bf6–àPC                       (4) QB–àCytbf6 DCMU inhibits photosynthesis at the step (2) QA → […]

DCMU inhibits electron transport in chloroplast by preventing the reduction of (1) P680. (2) QA. (3) PQ. (4) QB DCMU inhibits electron transport in chloroplasts by preventing the reduction of […]

Following are some facts regarding localization of photosynthetic supramolecular complexes on plastid lamellae: A. PSII is preferentially localized on granal lamellae B. ATP synthase and PSI is preferentially localized in […]

38. Following are statements related to the organization of the four major protein complexes of thylakoid membrane, A. Photosystem II is located predominantly in the stacked regions of the thylakoid […]

37. The following are certain statements regarding the PSII electron         carrier during          the          light   reaction of photosynthesis: A. The first electron released from reaction centre P680 is transferred to […]

36. The following statements refer to photosystem structure and function involved in light-dependent reaction of photosynthesis: A. The antenna or light harvesting complex absorbs light energy and transfers it to […]