Hh binds to Ptc, causing Ptc to be endocytosed from the cell surface and degraded, relieving the inhibition of Smo.

TLS Online TPP Program

#Id: 782

#Unit 3. Fundamental Processes

1100 sequences in the E. coli genome that fit these criteria, suggesting more than half of the cell’s transcripts are terminated at intrinsic terminators.

TLS Online TPP Program

#Id: 6286

#Unit 3. Fundamental Processes

The overall reaction rate for the bacterial RNA polymerase can be as fast as 40–50 nucleotides/ second at 37°C for most transcripts; this is about the same as the rate of translation (15 amino acids/sec), but much slower than the rate of DNA replication (800 bp/sec).

TLS Online TPP Program

#Id: 8768

#Unit 1. Molecules and their Interaction Relevant to Biology

TLS Online TPP Program

#Id: 613

#Unit 2. Cellular Organization

trp operon can run even in the presence of repressor. The attenuation system permits another 10-fold control over the operon’s activity. 

Thus, the combination of repression and attenuation controls the operon over a 700-fold range, from fully inactive to fully active: (70-fold [repression] X 10-fold [attenuation] = 700-fold). 

TLS Online TPP Program

#Id: 7343

#Unit 11. Evolution and Behavior