Which of these haploid strains produces ?-galactosidaseconstitutively but does not produce permease?

I^- P⁺ O⁺ Z⁺Y⁺

I⁺ P⁺ O⁺ Z^-Y^-

I^- P⁺ O⁺ Z^-Y⁺

I⁺ P⁺ O^- Z⁺Y⁺

I^- P⁺ O⁺ Z⁺Y^-

During the attenuation of the trp operon, whichstem loop leads to polycistronic mRNA synthesis during tryptophanstarvation?

2-3 (antitermination) stem loop

2-4 (termination) stem loop

3-4 (termination) stem loop

1-3 (antitermination) stem loop

1-2 (pause) stem loop

Which of the following mutations will result in thegreatest decrease in the efficiency of attenuation?

mutations that disrupt formation of the 1?2 hairpin

mutations that disrupt formation of the 2?3 hairpin

mutations that disrupt formation of the 3?4 hairpin

mutations that alter the terminal (3?) U nucleotide in thepoly-U segment

For each of the following E. coli partialdiploid strains, indicate whether expression of ?-galactosidase andpermease is inducible (I), constitutive (C), or negative (noproduct made) (N). Assume glucose levels are very low.

You have identified a mutation in a gene that also seemsto decrease transcription of another gene 2000 bp away from themutation site. What regulatory sequence, which may be found withinanother gene, has likely been mutated in thisinstance?

proximal elements

core promoter

upstream activator sequence

homeodomain motif

enhancer sequence

1 2 3 I+P+O+Z-Y-A+/ I-P+O+Z+Y+A+ I+P+O+Z-Y-A+/I+P+ OC Z+Y+A+ I+P+O+Z-Y-A+/ Is P+ O+Z+Y+A+ B-galactosidase Permease