A series of 3 G-C pairs in the stem that precedes the loop containing the anticodon is unique to tRNAf Met. These base pairs are required to allow the fMet- tRNAf to be inserted directly into the P site.

TLS Online TPP Program

#Id: 2453

#Unit 3. Fundamental Processes

Allolactose binds to a part of the Lac repressor distinct from its DNA-binding domain.

TLS Online TPP Program

#Id: 2454

#Unit 3. Fundamental Processes

Negative control of the lac operon. 

No lactose; repression. The lacI gene produces repressor, which binds to the operator and blocks RNA polymerase from transcribing the lac genes.

TLS Online TPP Program

#Id: 2455

#Unit 3. Fundamental Processes

Binding of the repressor to the operator sequence blocks binding of RNA polymerase and so inhibits transcription.

TLS Online TPP Program

#Id: 6654

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6655

#Unit 3. Fundamental Processes

The phosphorylation pattern on the CTD is dynamic during the elongation process, catalyzed and controlled by multiple protein kinases, including P-TEFb, and phosphatases.

TLS Online TPP Program

#Id: 6656

#Unit 3. Fundamental Processes

Shortly after transcription initiation, Pol II is paused 30 nucleotides downstream from the initiation site, waiting for the recruitment of the capping enzymes to add the cap to the 5’ end of nascent RNA. Without this protection, nascent RNA may be vulnerable to attack by 5’–3’ exonucleases, and such trimming may induce the Pol II complex to fall off of the DNA template.