PHOTOSYNTHESIS: AN OVERVIEW LIGHT-DEPENDENT REACTION/ LIGHT REACTION/ PHOTOPHOSPHORYLATION (“photo”)- takes place in the presence of light on the thylakoid membranes 1. Chlorophyll absorbs light energy , which is immediately converted to electrical energy . The electrical energy is represented in the flow of electrons from the chlorophyll molecule. We say that the chlorophyll has become temporarily energized. 2. Some of the energy of the energized chlorophyll is used to make ATP by chemiosmosis (process of energy capture in which a proton gradient is created by means of electron transport and then used to drive the synthesis of ATP). The phosphorylation of ADP is referred to as photophosphorylation. During this process, electrical energy is transformed to chemical energy . 3. Some of the light energy trapped is used to split water , a process called photolysis . Oxygen from the water is released . Some of this oxygen is used by the plant for photorespiration, but most of it is released into
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This note was uploaded on 12/06/2009 for the course BIO BLG143 taught by Professor Kimberleygilbride during the Spring '09 term at Ryerson.