Main Difference

Cyclic photophosphorylation produces ATP only, Phosphorylation is the mechanism by which phosphate group is added to a compound or molecule. It takes place in all living organisms, but photophosphorylation is the type of phosphorylation that only takes place in plants and some bacteria (not in human). Following that, cyclic photophosphorylation is the process that involves cyclic electron transport, whereas non-cyclic photophosphorylation is the process that does not involve a cyclic electron transport. The other prominent difference between both of these processes is that cyclic photophosphorylation only produces ATP, while non-cyclic produces both, ATP and NADP.

Comparison Chart

What is Cyclic Photophosphorylation?

It is the process of photophosphorylation that contains a cyclic transport of electrons, its active center for the reaction is photosystem1 (P700), it does not involve photosystem2 (P680). Cyclic photophosphorylation involves photosystem1, in this process electrons travel in a cyclic manner and travel back to photosystem1. In this process adenosine triphosphate (ATP) is produced that is utilized by plants as an energy source, this ATP is used in the Calvin Cycle. The process of Calvin cycle is directly dependent on the presence of the ATP, in case if there are no sufficient ATP’s, the process does not proceed further. Cyclic photophosphorylation does not involve the production of oxygen, photolysis (water splitting) is also absent in this. Furthermore, this process does not produce NADP and oxygen but still produces ATP. The process of cyclic photophosphorylation takes place mostly in bacteria; it is less seen in plants.

What is Non Cyclic Photophosphorylation?

It is the process of photophosphorylation that does not have a cyclic transport of electrons, its active center for the reaction is photosystem2 (P680), but is also involve in photosystem1 (P700). In noncyclic photophosphorylation. The transport of electrons is in a non-cyclic manner, these electrons from the photosystem1 (P700) are accepted by NADP. In non-cyclic photophosphorylation ATP and NADP both are produced that are utilized as an energy source, (NADP is a rich energy source as 1 NADP give energy equivalent to 3 ATPs). In non-cyclic photophosphorylation oxygen is evolved as a by-product of the reaction and is finally emitted in the surrounding environment, it also has photolysis in it, or water splitting is present. The process of non-cyclic photophosphorylation is mostly seen in green plants.

Cyclic Photophosphorylation vs. Non Cyclic Photophosphorylation

• Cyclic photophosphorylation has a cyclic electron transport, while non-cyclic photophosphorylation has a non-cyclic order of electron transport.
• Cyclic photophosphorylation has active center P700 whereas, non-cyclic photophosphorylation has active center
• Cyclic photophosphorylation involves photosystem1 only, but non-cyclic photophosphorylation involves photosystem1 and photosystem2 in it.
• Cyclic photophosphorylation produces ATP only, but counter to this noncyclic photophosphorylation produces both, ATP and NADP.
• In cyclic photophosphorylation, the electron travels back to photosystem1, while in noncyclic photophosphorylation the electrons from photosystem1 are accepted by NADP.
• Cyclic photophosphorylation does not evolve oxygen and does not contain photolysis of water while noncyclic photophosphorylation eliminate oxygen as a by-product of the reaction and it has photolysis of water in it.
• Cyclic photophosphorylation produces ATP without producing oxygen and NADP, whereas noncyclic photophosphorylation produces ATP, NADP, and oxygen.
• Cyclic photophosphorylation takes place predominantly in bacteria, whereas noncyclic photophosphorylation takes place mostly in green plants.