Question

What is 'photophosphorylation'? Describe non-cyclic photo-phosphorylation with schematic representation. Give its significance.

Answer 1

Photophosphorylation is the process in which phosphate group is transferred to ADP for the synthesis of energy-rich ATP molecule in the presence of light.

Non-cyclic photophosphorylation takes place as follows-

-The electrons lost by P680 are taken up by P700. These electrons do not go back to P680 hence it is called non- cyclic phosphorylation.

- The electrons pass through the primary acceptor, plastoquinone, cytochrome complex, plastocyanin and lastly to P700.

- The electrons released by P700 combine with H+ (obtained by splitting up water) and reduce NADP to NADPH.

Significance of non-cyclic photophosphorylation-

Non-cyclic phosphorylation results in the formation of oxygen, NADPH and ATP molecules.