Answer :
An electron transport chain (ETC) is a series of proteins and other molecules embedded in a membrane, which transfer electrons from one molecule to the next. The ETC plays a key role in cellular respiration, photosynthesis, and other metabolic processes that involve the transfer of energy in living cells.
During the light reactions of photosynthesis, the ETC is located in the thylakoid membrane of the chloroplast. Its role is to transport electrons and protons from water to NADP+ (nicotinamide adenine dinucleotide phosphate) to form NADPH, which is a key energy carrier in photosynthesis.
In summary, the electron transport chain is a crucial component of the light reactions of photosynthesis, where it helps to generate energy-rich molecules (NADPH and ATP) that are used in the next stage of photosynthesis, the Calvin cycle.