Photosynthesis In Higher Plants

In C plants, chloroplasts of mesophyll cells are smaller, grana rich and do not produce starch but chloroplasts of bundle sheath cells are larger and lack grana.

PSII is located in appressed part of grana thylakoids. It has chlorophyll a, b and carotenoids. lt consists of a photocentre P, oxygen evolving complex, light harvesting complex (LHC II) and some electron carriers. Oxygen evolving complex contains Mn, Ca and Cl.

During Calvin cycle, biphosphoglyceric acid is reduced by NADPH through the agencyofenzymeglyceradehyde3-phosphate dehydrogenase. It produces glyceraldehyde 3-phosphate or 3-phosphoglyceraldehyde.

Organisms which prepare their food themselves are called autotrophs. Autotrophs may be phototrophs or chemotrophs depending upon the energy source. When the energy .to initiate organic food synthesis is obtained from light rays the process is called phototrophism and the organisms are called phototrophs. But when oxidation of inorganic chemical compounds provide this energy, the organisms are called chemotrophs.