The tac promoter, an artificial promoter made from portions of the frp and lacUV5 promoters, has been introduced into a plasmid. It is a hybrid of the lac and trp (tryptophan) promoters, containing the –35 region of one and the -10 region of the other. This promoter directs transcription initiation more efficiently than either the trp or lac promoters. Why?

ennar region of gene X, which determines the length of the tail in mice, is mutated so that transcription factors bind it at a much higher affinity compared to the wild-type sequence. What is the most likely phenotypic outcome? Tail length will not change because the enhancer is a non-coding sequence Tail length will increased due to increased activity of the gene's promoter Tail length will decreased because any mutation will cause a loss-of-function of these regulatory regions Not just the tail will be enlarged because increased activity of the enhancer will impact many genes

Explain why inserting 5 bp of DNA at the –50 position of a eukaryotic gene decreases the rate of RNA polymerase II transcription initiation to a greater extent than inserting 10 bp at the same site.

For each of the following conditions in the Lac Operon, state whether transcription will occur or not and state why. Include all the major actors including glucose, lactose, cAMP and CAP(CPR). Key + (present) - (absent) 1) Glucose-; Lactose- 2) Glucose+; Lactose- 3) Glucose+; Lactose+ 4) Glucose-; Lactose+

Give the levels of Beta-galactosidase activity (high or low or zero) expected for the following partial diploids for the lac operon strains.

If the lacZ protein breaks down lactose, is it worthwhile to make it when there is no lactose around? How does the bacteria use this system to efficiently control the production of the lacZ protein? Does the presence of lactose in the cell alter its ability to repress translation? To what does the lacI protein bind to? What effect does the lacI gene have on transcription of the lacZ and lacY genes?

In a typical enzyme-catalyzed reaction, what are the relative concentrations of reactants and products as compared to the enzyme concentration?

A newly identified protein from the  cells of the Panopyra plant on Pandora was shown to inhibit translation of its target genes by binding to the 5’ UTR of the mRNA and preventing ribosome binding.  A possible way this inhibition may be relieved by an sRNA would be:  Group of answer choices a)The sRNA acts as a silencer, suppressing the inhibitory protein and allowing translation to take place. b)The sRNA acts as a decoy, sequestering the inhibitory protein and allowing translation to take place. c)The sRNA acts as a marker, flagging the inhibitory protein for ubiquitination and allowing translation to take place.

Another mutant for of the Lac promoter demonstrates the characteristics below compared to the wild-type promoter. The RNA Polymerase Holoenzyme binds tighter to the mutant promoter, but has reduced promoter activity in an assay with the promoter fuse to the gene for Green Fluorescent Protein (GFP). Provide a plausible explanation for this data. Lac Promoter Activity punog Binding of RNA Pol Holoenzymes to Promoters 120 100 80 60 40 20 0 0 20 40 Lac Promoter X 60 [DNA] nM 80 100 120 GFP Fluorecence 100 90 80 70 60 50 40 30 20 10 0 Lac Promoter X

What would be the effect on transcription of a short insertional mutation between the-10 box and the +1 site of transcription?