Exam 16: Regulation of Gene Expression

A certain enzyme is synthesized whenever the solution in which cells are growing contains substance X.This phenomenon is most likely an example of a(n) _______ system.

Which molecule acts as a co-repressor to block transcription of the tryptophan operon?

Suppose that in a strain of mice, specific bases on DNA are methylated but that these methylation changes are not stable and are erased before they can be passed on to the next generation.The name of the enzyme that is made defective in these mice is most likely _______.

A strain of HIV has more termination of partial transcripts than is typical.The most likely cause is a mutation

Alternative splicing is controlled by

DNA in eukaryotes is wrapped around special proteins to form structures that look like beads on a string.These structures are called _______.

A protein-coding gene in a eukaryote has four exons and three introns in the following arrangement. Assuming that transcription begins at exon 1 and ends after exon 4, how many different proteins could be made by alternative splicing of the pre-mRNA from this gene?

A cue for the switch from lysogenic phase to lytic phase of a virus would involve _______.

Some viruses can cause cancer in the long term by allowing progression through the cell cycle.This could be due to labeling of certain cell cycle checkpoint molecules with _______, targeting them for the proteasome.

Which term would be associated with a prophage?

The binding of the inducer to the repressor causes the repressor to

Suppose lactose is in high concentration and glucose is in low concentration in the surrounding media, yet the cell is not taking in much lactose.The lactose that is taken in is quickly metabolized.The most likely explanation for this is a mutation in

All cells in a given mammal carry the same genome, yet certain genes are expressed only in a particular tissue, such as in the eye, and not expressed in other tissues, such as in the liver.How is this specificity of gene expression for a particular tissue achieved?

A strain of bacteria prefers to metabolize fructose, but it can grow on other sugars.When fructose is abundant, the expression of genes involved in metabolizing other sugars is much reduced.This is an example of _______.

A herpes virus causes both chicken pox and shingles in humans.People who have had chicken pox may be afflicted with shingles much later in life.The most likely explanation for this is that

What would happen initially to cells that lack a functional ubiquitin?

In the treatment of HIV, _______ are used because they block synthesis of viral DNA from RNA.

Conferring of epigenetic patterns onto offspring is called genomic imprinting.Genomic imprinting would likely be most affected by globally inhibiting the gene(s) for

In a fruit fly, the transcription rates of a gene that codes for an enzyme vary tremendously among different cell types.The most likely reason for these differences is that different cell types have different

Which genes would be considered to be composed of heterochromatin?