the light reactions of photosynthesis occur in photosystem ii.
the light reactions of photosynthesis occur in photosystem ii.
when do the light reactions of photosynthesis occur?
in photosystem ii
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::::function and chemistry.:photosynthesis.:light reactions.









































the light reactions take place on the thylakoid membranes. they take light energy and store it in nadph, a form of nadp, and atp to fuel the dark reactions.









































section::::function and chemistry.:photosynthesis.:light reactions.:energy carriers.









































atp is the phosphorylated version of adenosine diphosphate (adp), which stores energy in a cell and powers most cellular activities. atp is the energized form, while adp is the (partially) depleted form. nadp is an electron carrier which ferries high energy electrons. in the light reactions, it gets reduced, meaning it picks up electrons, becoming nadph.









































section::::function and chemistry.:photosynthesis.:light reactions.:photophosphorylation.
chloroplast