Question

Give a schematic representation of non-cyclic photophosphorylation showing both the photosystems.

Answer 1

The light-requiring part of photosynthesis in higher plants, in which an electron donor is required, and oxygen is produced as a waste product. It consists of two photoreactions, resulting in the synthesis of ATP and NADPH ₂. When photosystem II absorbs light, an electron excited to a higher energy level in the reaction centre chlorophyll (P680) is captured by the primary electron acceptor. This reaction splits a water molecule into two hydrogen ions and an oxygen atom, which immediately combines with another oxygen atom to form O₂.Each photoexcited electron (energized by light) passes from the primary electron acceptor in photosystem II to photosystem I via an electron transport chain.The production of ATP in the chloroplast is called photophosphorylation because the energy harnessed in the process originally came from light.The ATP generated in this process will provide the energy for the synthesis of glucose during the Calvin cycle (light independent reactions).