Non-cyclic Electron Transport in Photosynthesis

refers to the use of light energy to ultimately provide the energy to convert ADP to , thus replenishing the universal energy currency in living things. In the simplest systems in prokaryotes, is used just for the production of energy, and not for the building of any biological molecules. But in plants the photosynthesis process also provides energy in the form of which drive the process of biochemical synthesis culminating in the production of glucose and other sugars. This process uses both and acting in series. The above illustration is patterned after Moore and shows some of the steps of the non-cyclic electron transport process.

Non-cyclic photophosphorylation needs a constant supply of water molecules

If the light intensity is not a limiting factor, there will usually be a shortage of NADP+ as NADPH accumulates within the stroma (see light independent reaction). NADP+ is needed for the normal flow of electrons in the thylakoid membranes as it is the final electron acceptor. If NADP+ is not available then the normal flow of electrons is inhibited. However, there is an alternative pathway for ATP production in this case and it is called cyclic photophosphorylation. It begins with Photosystem I absorbing light and becoming photoactivated. The excited electrons from Photosystem I are then passed on to a chain of electron carriers between Photosystem I and II. These electrons travel along the chain of carriers back to Photosystem I and as they do so they cause the pumping of protons across the thylakoid membrane and therefore create a proton gradient. As explained previously, the protons move back across the thylakoid membrane through ATP synthase and as they do so, ATP is produced. Therefore, ATP can be produced even when there is a shortage of NADP+.

Differences between Cyclic and Non Cyclic Photophosphorylation

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.

09/01/2008 · and what does cyclic and non-cyclic mean

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.

What are the Cyclic and Non-Cyclic Pathways in Photosynthesis

Cyclic electron flow helps move the electrons throughout photosystem 1 for cyclic photophosphorylation.
Noncyclic electron flow moves electrons through both Photosystem 1 and 2.

Cyclic vs Noncyclic Phosphorylation - Table | …

One for Cyclic Photophosphorylation, and one for Noncyclic photophosphorylation.
A haiku is a lyric poem that consists of 5 syllables the first line, 7 the second line, and 5 again the last line.