Plant viruses are biotrophs and they enters in the plants via plasmodesmata and phloem

TLS Online TPP Program

#Id: 2340

#Unit 3. Fundamental Processes

When bound to the ribosome, stringent factor catalyzes formation of the unusual nucleotide guanosine tetraphosphate (ppGpp); it adds pyrophosphate to the 3 position of GTP, in the reaction.

TLS Online TPP Program

#Id: 2341

#Unit 3. Fundamental Processes

Bacterial promoters

TLS Online TPP Program

#Id: 2342

#Unit 3. Fundamental Processes

The consensus sequence reflects preferred –10 and –35 regions, separated by the optimum spacing (17 bp).

TLS Online TPP Program

#Id: 2343

#Unit 3. Fundamental Processes

Promoters with sequences closer to the consensus are generally “stronger” than those that match less well

TLS Online TPP Program

#Id: 2344

#Unit 3. Fundamental Processes

consensus sequence of TATAAT in which the leading TA and the final T are highly conserved. Upstream sequences around position –35 also have a region of sequence similarity, TTGACA. 

TLS Online TPP Program

#Id: 2345

#Unit 3. Fundamental Processes

Core enzyme binds indiscriminately to any DNA. Sigma factor reduces the affinity for sequence independent binding and confers specificity for promoter.