Three states of a neuron

TLS Online TPP Program

#Id: 3412

#Unit 3. Fundamental Processes

SOS response in E. coli:

When DNA is extensively damaged (such as by UV light), DNA replication is halted and the number of single-strand gaps in the DNA increases.

RecA protein binds to this damaged, single-stranded DNA, activating the protein’s co-protease activity.

While bound to DNA, the RecA protein facilitates cleavage and inactivation of the LexA repressor. When the repressor is inactivated, the SOS genes, including RecA, are induced;

TLS Online TPP Program

#Id: 3417

#Unit 3. Fundamental Processes

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: 3418

#Unit 3. Fundamental Processes

NHEJ is a backup system in yeast, but in higher cells it is the principal pathway by which breaks are repaired.

TLS Online TPP Program

#Id: 3419

#Unit 3. Fundamental Processes

Ku70 and Ku80 are the most fundamental components of NHEJ. They constitute a heterodimer that binds to the DNA ends and recruits DNA-PKcs, which is a protein kinase

TLS Online TPP Program

#Id: 3420

#Unit 3. Fundamental Processes

Mammalian pathway for NHEJ

TLS Online TPP Program

#Id: 5022

#Unit 3. Fundamental Processes

Interphase = G1 + S + G2

The start of S phase is signaled by the activation of the first replicon, usually in euchromatin, in areas of active genes.