What Is Linear and Cyclic Electron Flow

In linear electron flow (LEF), the PSs function in series and electrons are transferred all the way from water to NADP+ with concomitant production of NADPH and ATP. Cyclic electron flow (CEF), in contrast, recycles electrons around PSI by re-routing them from ferredoxin (Fd) to the plastoquinone (PQ).

What is the physiological difference between cyclic and linear electron flow?

The reactions involve two types of electron flow in the thylakoid membrane. While linear electron transport generates both ATP and NADPH, cyclic electron transport around photosystem I (PS I) is exclusively involved in ATP synthesis without the accumulation of NADPH.

What is cyclic flow?

In cyclic electron flow (CEF), electrons are recycled around photosystem I. As a result, a transthylakoid proton gradient (ΔpH) is generated, leading to the production of ATP without concomitant production of NADPH, thus increasing the ATP/NADPH ratio within the chloroplast.