In light reaction, plastoquinone facilitates the transfer of electrons from

In chloroplast, both light and dark reaction of photosynthesis takes place. In the disc of thylakoid, the light reaction takes place where water is oxidized to release oxygen. The transfer of electrons is facilitated by plastoquinone from PS-II to Cytb₆f complex, in the light reaction. The electrons which are freed from water a transfer to ATP and NADPH. The dark reaction occurs outside the thylakoid, in the stroma and cytoplasm, and in this reaction, the energy from ATP and NADPH are utilized to fix carbon dioxide. Sugar molecules and other organic molecules which are necessary for the cell function in metabolism are products of this reaction.