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1. Would you expect modulation of chromatin structure to be important in the regulation of bacterial gene expression? Why or why not? (You may want to look back at chapter 9 for more information on the structure of bacterial chromosomes in order to answer this question.)

2. Would you say that the lac repressor gene, lac i, is part of the lac operon? Why or why not? (What constitutes an operon?)

3. A bacterial strain has a mutation in the gene encoding adenyl cyclase, the enzyme that makes cAMP from ATP. The mutation results in a constitutively active enzyme, and thus constitutively high levels of cAMP. What levels of beta-galactosidase expression would you expect to see in this strain in the presence of glucose only? Glucose plus lactose? Lactose only? (Assume that all other genes and DNA elements important to the regulation of the lac operon are wild-type in this strain.)

4. Your textbook briefly describes the isolation of CAP as a cAMP-binding protein that is absent in mutant cells unable to activate alternate metabolic pathways (such as lac) in response to an increase in cAMP. We discussed this isolation method in class as well. Propose an alternate method that could have been used to isolate and identify this protein.

5. You've isolated and identified a eukaryotic transcriptional activator that is important in the regulated expression of your-favorite-gene. To further characterize this activator, you conduct an experiment designed to detect protein-protein interactions. You determine that your activator interacts with TBP, a subunit of the eukaryotic general transcription factor TFIID. Propose a mechanism by which your activator might stimulate transcription of your-favorite-gene. (Your answer should demonstrate that you know what TBP is and what role it plays in eukaryotic transcriptional activation.)

6. (extra credit, up to two points) Propose an experiment or series of experiments that you could use to explore whether the mechanism you proposed in #5 is in fact correct.

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