Cyclic Electron Transport in Photosynthesis

Light reaction and photophosphorylation
Pigments embedded on thylakoid membranes form photosystems. There are of two types: PS I P700, PS II P680. Components of photosystem I and II transfer the electrons from water to NADP via cyclic electron transfer or non-cyclic electron transfer. During electron transfer, the light energy captured by the photosynthetic organisms is transformed into the phosphate bond energy of ATP. This is called photophosphorylation. NADPH is generated during non-cyclic electron transfer.

This pathway produces ATP and a reduced electron carrier (NADPH + H ).

Munekage Y, Hojo M, Meurer J et al. (2002) PGR5 is involved in cyclic electron flow around photosystem I and is essential for photoprotection in Arabidopsis. Cell 110: 361–371.


Noncyclic Electron Flow - Biology As Poetry

· C4 is the alternative pathway of Calvin cycle (C3 cycle) taking place during the dark phase of photosynthesis.

Cyclic photophosphorylation takes electron excited to the PSI electron acceptor and instead of sending them to NADPH, deposits them on Plastocyanin (PC) in the electron transport chain between PSII and PSI. These electrons then flow down in the cycle. The pathway of electron as follows;


Hill and Bendall's Z-scheme of cyclic and non-cyclic ..

In plants photosynthesis results in the production of ATP and NADPH by a two step process known as non- cyclic photophosphorylation. It is called non- cyclic photophosphorylation because in the light reaction of photosynthesis, there is one way flow of electron from chlorophyll to the electron carrier NADPH. Both PSI and PSII are involved. This process takes place in green plants. DCMU inhibits this process. In this process electrons are released from PSII and later they are utilized in PSI and does not come back.

19/12/2017 · A non-cyclic pathway is ..

Light reaction and photophosphorylation
Pigments embedded on thylakoid membranes form photosystems. There are of two types: PS I P700, PS II P680. Components of photosystem I and II transfer the electrons from water to NADP via cyclic electron transfer or non-cyclic electron transfer. During electron transfer, the light energy captured by the photosynthetic organisms is transformed into the phosphate bond energy of ATP. This is called photophosphorylation. NADPH is generated during non-cyclic electron transfer.

Non-cyclic photoreductive carbon fixation in photosynthesis

Heber U (2002) Irrungen, Wirrungen? The Mehler reaction in relation to cyclic electron transport in C3 plants. Photosynthesis Research 73: 223–231.

Photosystem II, the Evolution of Non-cyclic Photosynthesis

The light-independant reactions of photosynthesis occur in the stroma of the chloroplast and involve the conversion of carbon dioxide and other compounds into glucose. The light-independent reactions can be split into three stages, these are carbon fixation, the reduction reactions and finally the regeneration of ribulose bisphosphate. Collectively these stages are known as the Calvin Cycle.