How is the movement of electrons in ETC in light reaction?

Options

(a) Uphill in terms of redox reaction
(b) down hill in terms of redox reaction
(c) Either Uphill in terms of redox reaction & down hill in terms of redox reaction
(d) Both Uphill in terms of redox reaction & down hill in terms of redox reaction

Correct Answer:

down hill in terms of redox reaction

Explanation:

In ETC of photosynthesis, the movement of electrons is downhill in terms of oxidation reduction or redox potential scale. The electrons are not used up as they pass through the electron transport chain, but they are passed simultaneously, electrons in the reaction centre of PS-I are also excited. When they receive red light of wavelength 700 nm and are transferred to another acceptor molecule that has greater redox potential. These electrons then are moved down hill again, this time to a molecule of ener