Light-dependent and Light-independent Stages of Photosynthesis

Photosynthesis

Light-dependent Stage

The light-dependent stage of photosynthesis occurs in the thylakoid membrane of the grana. The sunlight hits the photosystem in the thylakoid membrane and the light energy raises 2 of its electrons to a higher energy level placing them in an 'excited state'. These electrons leave the photosystem and are passed along a series of electron carriers via redox reactions (reduction and oxidation). These electron carriers make up the electron transport chain (ETC). During ETC, the electrons lose energy which is used in the synthesis of ATP by reacting ADP with Pi. This process is called photophosphorylation. Then photolysis occurs. This occurs in the thylakoid space and is where an enzyme catalyses the…