Under certain conditions, the photoexcited electrons take an alternative path called cyclic electron flow, which uses photosystem I (P700) but not photosystem II (P680). This process produces no NADPH and no O2, but it does make ATP. This is called cyclic photophosphorylation.
Is photosystem 1 and 2 cyclic or noncyclic?
Difference between Cyclic and Non-Cyclic Photophosphorylation
| Cyclic Photophosphorylation | Non-Cyclic Photophosphorylation |
|---|---|
| Only Photosystem I is involved. | Both Photosystem I and II are involved. |
| P700 is the active reaction centre. | P680 is the active reaction centre. |
How many photosystems are involved in cyclic photophosphorylation?
There are two types of photosystems: photosystem I (PSI) and photosystem II (PSII).
What are photosystem 1 and 2?
Photosystem I (PS I) and photosystem II (PS II) are two multi-subunit membrane-protein complexes involved in oxygenic photosynthesis. The main difference between photosystem 1 and 2 is that PS I absorbs longer wavelengths of light (>680 nm) whereas PS II absorbs shorter wavelengths of light (<680 nm).
Is photosystem 1 cyclic or non cyclic?
Photosystem I is involved in the cyclic photophosphorylation process. In the cyclic photophosphorylation, P700 is known to be the active reaction centre.
What are cyclic and non-cyclic process?
A cyclic process consists of a series of changes which return the system back to its initial state. In non – cyclic process the series of changes involved do not return the system back to its initial state.
Which photosystem is operational during cyclic photophosphorylation?
photosystem-I
Cyclic photophosphorylation involves the use of photosystem-I. When light is absorbed by this photosystem, the excited electron enters the electron transport chain to produce ATP.
What is PS1 and PS2?
PS1 and PS2 are homologous polytopic membrane proteins that are processed endoproteolyti- cally into two fragments in vivo. In the present report we examine the fate of endogenous PS1 and PS2 after over- expression of human PS1 or PS2 in mouse N2a neuro- blastoma cell lines and human PS1 in transgenic mice.
What does photosystem 1 do in photosynthesis?
Photosystem I is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. Ultimately, the electrons that are transferred by Photosystem I are used to produce the high energy carrier NADPH.
What is cyclic photophosphorylation and how does it work?
Cyclic Photophosphorylation happens with the help of photosynthesis, a process of producing carbohydrates by green plants using carbon dioxide and water in the presence of sunlight. The two-step process comprises of:
Where does photophosphorylation usually occur in the human body?
This type of photophosphorylation usually occurs in the thylakoid membrane. The electron begins in a pigment complex called photosystem I in cyclic electron flow.
What is the role of light energy in photophosphorylation?
In photophosphorylation process, light energy is used to make a high-energy electron donor and a lower-energy electron acceptor. Electrons then move suddenly from donor to acceptor through an electron transport chain.
Which type of photophosphorylation is also known as Z-scheme?
1. Noncyclic Photophosphorylation: It is also called as Z-scheme. In this type, an electron from chlorophyll travel through the electron transport system and then, reduce NADP+ to form a molecule of NADPH.
