Photosynthesis-Calvin Cycle and Cyclic Electron Flow …

Miyake C, Horiguchi S, Makino A et al. (2005) Effects of light intensity on cyclic electron flow around PSI and its relationship to non‐photochemical quenching of Chl fluorescence in tobacco leaves. Plant and Cell Physiology 46: 1819–1830.

Cyclic Electron Flow - Biology As Poetry

The blue arrows indicate the flow of electrons through an electron transport chain (ETC).

Non-cyclic Electron Flow (photosynthesis light …

Cyclic
Noncyclic Photophosphorylation uses both photosystems 1 and 2.
The electrons transport in a noncyclic manner.
The active reaction center uses P680.

Recent studies show that the cyclic electron flow ..


Photolysis, water splitting, is present.
Oxygen changes during the process.
Takes place in plants.
Noncyclic Diagram
Cyclic Photophosphorylation
Uses only Photosystem 1
The reaction center is P700
The electrons travel in a cyclic manner
Photolysis is not present.
Oxygen does not change throughout the process.
Most often used by bacteria.
Steps That Lead to Phosphorylation
Photosynthesis is a two step process that consists of the light and dark reactions.
Photophosphorylation is the process of generating ATP from ADP , by proton motive force generated by the thylakoid membrane.
Photophosphorylation takes place during the light reaction step in photosynthesis.
In light reaction, the addition of phosphate in the presence of light is called photophosphorylation.

It is non-cyclic because the electrons travel in a Z- shape (in redox potential space) and do not end where they started.

What are the differences between cyclic and noncyclic electron flow

Photosynthesis is a process where by energy from light is harvested and used to drive synthesis of carbohydrates from carbon dioxide and water. Photophosphorylation is a process where the light energy captured by the photosynthetic organisms is transformed into the phosphate bond energy of ATP. Components of photosystem I and II transfer the electrons from water to NADP. Second step of photosynthesis is called Calvin’s cycle and it is a dark reaction. There are two stages here, I and II. Stage I is carbon dioxide fixation and stage II is the regeneration phase. Photorespiration is the process wherein oxygen consumption occurs in illuminated temperature zone of plants under high oxygen and low carbon dioxide. C4 cycle is the pathway adopted by C4 plants to conserve the carbon dioxide released via photorespiration. It occurs in mesophyll cells.

of non-cyclic electron flow in green plants ..

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

Munekage Y, Hashimoto M, Miyake C et al. (2004) Cyclic electron flow around photosystem I is essential for photosynthesis. Nature 429: 579–582.

Cyclic electron flow around photosystem I via …

Cyclic electron transport is a light‐driven flow of electrons through a photosynthetic reaction centre with the electrons returning to the reaction centre via an electron transport pathway. Cyclic electron transport will normally generate an electrochemical potential (typically pH) gradient across a membrane but does not result in the net production of reductant. The pH gradient generated may drive the production of adenosine triphosphate (ATP) (cyclic photophosphorylation) or may regulate photosynthesis.

Cyclic DiagramConnections to Electron FlowBoth cyclic and noncyclic photophosphorylation have an electron flow.

The function of cyclic electron transport in photosynthesis

Laisk A, Eichelmann H, Oja V, Rasulov B and Ramma H (2006) Photosystem II cycle and alternative electron flow in leaves. Plant and Cell Physiology 47: 972–983.

It is suggested that the bacteria mediate the electron flow either by the  or by some unknown conducting mechanism.

Cyclic vs. Non-cyclic Electron Flow - Mandeville High …


These electron flows prevent the Photosystems from fully reducing all the electron carriers and causing photosynthesis to stop.
Instead, electrons can be donated to cytochrome bf instead of NADP.
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