Alternative models for translesion synthesisIn; Two models explain the mechanism of translesion synthesis, each likely to be true under particular circumstances.

The polymerase-switching model,

The gap-filling model,

TLS Online TPP Program

#Id: 8825

#Unit 6. System Physiology – Plant

Cyclic electron transport pathway is catalyzed by the NADH dehydrogenase‐like (NDH) complex in the thylakoid

membrane. This large complex is similar to mitochondrial Complex I,

TLS Online TPP Program

#Id: 8826

#Unit 6. System Physiology – Plant

The NDH pathway is especially prominent during oxidative stress. 

The second pathway involves a ferredoxin‐quinone oxidoreductase that is sensitive to antimycin A.

TLS Online TPP Program

#Id: 8827

#Unit 6. System Physiology – Plant

Some of the cytochrome b6 f complexes are found in the stroma region of the membrane, where photosystem I is located. Under certain conditions cyclic electron flow from the reducing side of photosystem I, through the b6 f complex and back to P700, is known to occur.

TLS Online TPP Program

#Id: 8828

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 8829

#Unit 6. System Physiology – Plant

When PSII receives more light than PSI, plastoquinone becomes predominantly reduced, resulting in activation of the LHCII kinase. The kinase phosphorylates LHCII, resulting in migration of LHCII away from the granal region where it can associate with PSI, thereby adjusting the relative excitation of PSII and PSI.

TLS Online TPP Program

#Id: 8830

#Unit 6. System Physiology – Plant

STN7 kinase mediated phosphorylation of LHCII molecules displace them to PSI