Which of these products is formed during the electron transport chain?

During the electron transport chain, ATP is synthesized as a key product. This process occurs in the mitochondria of eukaryotic cells, where electrons are transferred through a series of protein complexes. These transfers create a proton gradient across the inner mitochondrial membrane. Ultimately, this gradient drives ATP synthase, the enzyme that produces ATP from ADP and inorganic phosphate.

While NADH and FADH2 are crucial electron carriers in cellular respiration, donating electrons to the electron transport chain, they are not products of the chain itself. Instead, they are oxidized during the process, contributing to the energy conversion but not being formed as a direct outcome. Hence, the correct option highlights ATP as the main product, emphasizing its role as the primary energy currency of the cell resulting from the processes occurring in the electron transport chain.