the most immediate role of water in the light dependent reactions is as the first electron donor.
what is the most immediate role of water in the light dependent reactions?
the first electron donor
the four photosystems absorb light energy through pigments—primarily the chlorophylls, which are responsible for the green color of leaves. the light-dependent reactions begin in photosystem ii. when a chlorophyll "a" molecule within the reaction center of psii absorbs a photon, an electron in this molecule attains a higher energy level. because this state of an electron is very unstable, the electron is transferred from one to another molecule creating a chain of redox reactions, called an electron transport chain (etc). the electron flow goes from psii to cytochrome "bf" to psi. in psi, the electron gets the energy from another photon. the final electron acceptor is nadp. in oxygenic photosynthesis, the first electron donor is water, creating oxygen as a waste product. in anoxygenic photosynthesis various electron donors are used.
light-dependent reactions
section::::light dependent reactions.





















































in chemistry, there are many different reactions which are dependent on the absorption of photons to provide energy for the reaction kinetics, and hence can be labelled light-dependent. such reactions range from the silver halide reactions used in photographic film to the creation and destruction of ozone in the upper atmosphere. this article discusses specific subset of these, the series of light-dependent reactions related to the chemical synthesis ([photosynthesis]]} in living organisms.





















































section::::the reaction center.
light-dependent reactions