In the absence of allolactose, the repressor is present in a form that binds its site on DNA (and so keeps the lac genes switched off ). 

TLS Online TPP Program

#Id: 1490

#Unit 4. Cell Communication and Cell Signaling

p53 transcription is upregulated by growth factor stimulation, as the cell begins preparation for its trip through GI and the important GI to S transition.

TLS Online TPP Program

#Id: 5060

#Unit 3. Fundamental Processes

Input of energy in the form of ATP is required at several stages for the prepriming reaction, and it is required for unwinding DNA.

The helicase action of DnaB depends on ATP hydrolysis, and the swivel action of gyrase requires ATP hydrolysis.

ATP also is needed for the action of primase and to load the b subunit of Pol III in order to initiate DNA synthesis.

TLS Online TPP Program

#Id: 7256

#Unit 5. Developmental Biology

B-10 B cells release the interleukin IL-10 upon antigenic stimulation, and may serve to reduce inflammation during an ongoing immune response.

TLS Online TPP Program

#Id: 1418

#Unit 4. Cell Communication and Cell Signaling

Integrins are the principal receptors used by animal cells to bind to the extracellular matrix. 

 

TLS Online TPP Program

#Id: 10506

#Unit 4. Cell Communication and Cell Signaling

Human Bcl-2 and worm CED-9 both proteins contain a single TM domain and are localized to the outer mitochondrial membrane