Identify the correct statement(s) regarding the mechanism of light reaction in photosynthesis : A. In a photosystem, a single chlorophyll a molecule forms the reaction centre. B. Cyclic photophosphorylation occurs when only light of wavelengths beyond 680 nm are available for excitation. C. The NADP reductase enzyme is located on the lumen side of the thylakoid membrane. D. The breakdown of the proton gradient provid

Step-by-step solution

Statement A is correct. In a photosystem, the reaction centre is formed by a single chlorophyll a molecule. Statement B is correct. Cyclic photophosphorylation occurs when only light of wavelengths beyond 680 nm are available for excitation, as only PS I is functional. Statement C is incorrect. The NADP reductase enzyme is located on the stroma side of the thylakoid membrane, not the lumen side. Statement D is incorrect. The breakdown of the proton gradient provides energy to cause a conformational change in the CF