Exam 18: Regulation of Gene Expression

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If a researcher moves the promoter for the lac operon to the region between the beta galactosidase (lacZ) gene and the permease (lacY) gene, which of the following results would be most likely?

Under what conditions does the trp repressor block transcription of the trp operon?

Which of the following processes destroys RNA molecules in a cell if they have a sequence complementary to an introduced double-stranded RNA?

Cell differentiation always involves

Which of the following processes would allow the detection of alternative splicing of transcripts from a given gene?

According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon?

Which of the following molecules helps to "turn off" genes in a cell?

For a repressible operon to be transcribed, which of the following conditions must occur?

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If a researcher moves the operator to the far end of the operon, past the transacetylase (lacA) gene, which of the following processes would likely occur when the cell is exposed to lactose?

A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. One of her colleagues suggested she try increased methylation of cytosine (C) nucleotides in the DNA of promoters of a mammalian system. Which of the following results would she most likely see?

Which of the following statements correctly describes the primary difference between enhancers and proximal control elements?

There is a mutation that is found in E. coli in the repressor that results in a molecule known as a super-repressor because it represses the lac operon permanently. Which of the following characteristics would you expect to observe in such a mutant?

Forms of the Ras protein found in tumours usually cause which of the following events to occur?

Which of the following statements correctly describes a characteristic of tumour-suppressor gene?

Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror-image duplication of posterior parts. This is evidence that the product of the bicoid gene

Which of the following statements best describes the characteristics of siRNA?

Which of the following conditions is most likely to cause the lactose operon to be transcribed?

The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different ________.

Which of the following functions does the product of the p53 gene carry out?

Muscle cells differ from nerve cells mainly because they