a) The lux operon is under positive control. Based on this information, does the luxR regulator sequence make a repressor protein or an activator protein? b) How will binding of this complex affect RNA polymerase? Remember this operon is under positive control. c) AHL is a signal molecule that V. fisheri makes to communicate with neighboring bacterial cells. This molecule can diffuse outside of the cell and into another bacterial cell in close proximity. This type of communication between bacterial cells is known as quorum sensing. If bacterial cell density is low how will this affect the lux operon? What will happen if the density is high?

A mutation that inactivates the repressor gene of the lac operon results in (a) the continuous transcription of the structural genes (b) no transcription of the structural genes (c) the binding of the repressor to the operator (d) no production of RNA polymerase (e) no difference in the rate of transcription

INTERPRET DATA Develop a simple hypothesis that would explain the behavior of each of the following types of mutants in E. coli. Mutant a: The map position of this mutation is in the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if large amounts of tryptophan are present in the growth medium. Mutant b: The map position of this mutation is in the trp operon. The mutant cells do not produce any enzymes coded for by the trp operon under any conditions. Mutant c: The map position of this mutation is some distance from the trp operon. The mutant cells are constitutive; that is, they produce all the enzymes coded for by the trp operon, even if the growth medium contains large amounts of tryptophan.

In selecting target cells to receive a transferred gene in gene therapy, what factors do you think would have to be taken into account?