Difference between cyclic and non-cyclic phosphorylation

Let me share with you a difference between cyclic and non-cyclic phosphorylation.


Aspect Cyclic Photophosphorylation Non-Cyclic Photophosphorylation or Z-Scheme
Electron pathway Electrons follow a circular or cyclic pathway, returning to the same chlorophyll molecule Electrons follow a linear pathway, moving from water to NADP+
Destination of electrons Electrons return to Photosystem I Electrons move between both Photosystem II and Photosystem I
Production of ATP ATP is produced during cyclic electron flow ATP is produced during both Photosystem II and Photosystem I electron transport
Production of NADPH No NADPH is produced NADPH is produced in non-cyclic photophosphorylation
Oxygen evolution Lower or absent in cyclic Oxygen is evolved as a byproduct of water splitting in Photosystem II
Role in carbon fixation Does not directly contribute to carbon fixation Provides NADPH that are crucial for the reduction of carbon dioxide during the Calvin Cycle
Energy source Uses light energy absorbed by Photosystem I chlorophyll Utilizes light energy absorbed by both Photosystem II and Photosystem I chlorophylls
Occur in ·        Common in certain bacteria

·        Some photosynthetic algae

·        Plants

·        Algae

·        Cyanobacteria