Differences between Cyclic and Non-cyclic Photo phosphorylation

Cyclic Photo phosphorylation:

1. It is performed by photosystem I independently. 

2. An external source of electrons is not required. 

3. It is not connected with photolysis of water. Therefore, no oxygen is evolved. 

4. It synthesises only ATP. 

5. The system does not take part in photosynthesis except in certain bacteria. 

6. It occurs mostly in stromal or intergranal thylakoids. 

7. ATP synthesis is not affected by DCMU. 

8. It is helpful in photosynthesis only in some bacteria.

Non-cyclic Photo phosphorylation:

1. It is performed by collaboration of both photosystems II and I. 

2. The process requires an external electron donor. 

3. It is connected with photolysis of water and liberation of oxygen. 

4. Noncyclic photo phosphorylation is not only connected with ATP synthesis but also production of NADPH. 

5. The system is connected with C0₂ fixation. 

6. It occurs in the granal thylakoids. 

7. DCMU inhibits noncyclic photo phosphorylation. 

8. It takes part in photosynthesis in all plants including blue-green algae.