_______________________________________________________________________

u srijedu 11. listopada. u 16 sati u predavaonici 3. krila

Prof. Pierre Joliot, CNRS - IFR 550

Institut de Biologie Physico-Chimique

13,  rue  Pierre  et  Marie  Curie,  Paris,  France

Photosynthetic process in algae and plants can operate through linear mode than leads to electron transfer from water to NADP, and cyclic mode that is associated with ATP synthesis. It proposed that cyclic and linear pathways are in permanent competition for the reoxidation of the soluble PSI acceptor Ferredoxin (Fd). In the linear mode, Fd binds ferredoxine NADP reductase and electron are transferred to NADP+ and then to the Benson and Calvin cycle. In the cyclic mode Fd binds to a site localized on the

stromal side of the cytochrome b/f complex and electron are transferred to P700 via a mechanism derived from de Q cycle. In dark-adapted leaves, cyclic electron flow operates at a maximum rate, owing to the inactivation of the Benson and Calvin cycle. For increasing time of illumination, the activation of the Benson and Calvin cycle and thus of the linear flow, is associated with a partial inhibition of the cyclic flow. Rate of cyclic and linear processes are determined on the basis of P700 and fluorescence

measurements.