Name:

2. What is the difference between an inducer and a corepressor?

3. Which is easier to construct by random mutation - a constitutive lac operon or a constitutive ara operon? Why?

4. Give an example of a cis active verses trans active constitutive lac mutation.

5. Why is it better to use IPTG to induce the lac operon as opposed to lactose, when you are attempting expression of a gene cloned behind a lac promoter.

6. If the lac and trp operons are each negatively regulated, how is it that adding lactose to a culture induces the lac operon, but adding Trp represses the trp operon?

7. To what other genetic event is attenuation of the trp operon most similar?

8. What is the P1 form or AraC and how does it affect expression from the pBAD promoter (both in terms of up or down regulation and the mechanism of this regulation)?

9. How is the transport of glucose directly linked to the regulation of the catabolite repression system?

10. How is the heat shock alternative sigma factor, sigma-32 encoded by the rpoH gene, post-transcriptionally regulated? How does this regulation tie into the function of the heat shock regulon itself?

Extra credit - What is the phenotype of a lacI^q mutation at the level of gene expression?

Another extra credit - How is the LexA protein related to the action of RecA on the CI repressor of lambda?