Gene Regulation 2

Which of the following statements about enhancers is TRUE?

Enhancers are sequences to which activators bind.

Transcription is carried out by the enzyme

RNA polymerase

Assembly of basal transcription factors begins at the ________ sequence in the promoter.

TATA

Which of the statements is the best explanation for why eukaryotes use so many regulatory elements, such as activators, repressors, coactivators, and basal transcription factors?

The complexity allows specific control over the timing and quantity of the protein produced.

Which of the following statements best describes the consequence of a mutated activator on expression of a transcriptional target gene?

The gene will be expressed, but in less than optimal quantities.

Which of the following statement(s) about basal transcription factors is(are) TRUE?

They are essential for transcription and they cannot increase the rate of transcription by themselves.

Which statement represents the best explanation for why eukaryotes use basal, or general, transcription factors?

They give the cell tight control over transcription.

Identify the most accurate term related to chromatin remodeling. a. DNA is associated with proteins to form ____________ b. A ____________ is composed of DNA wrapped around an octamer of histone proteins. c. An activator can increase transcription by attracting a ____________ to the region. d. Addition of (-COCH3) groups to histone amino terminal tails results in a/an ____________ in gene expression. e. Removal of acetyl groups from histones results in a/an ____________ in gene expression.

a. chromatin b. nucleosome c. histone acetyltransferase d. increase e. decrease

Determine whether each described change to chromatin structure would increase or decrease gene expression. a. Decrease in gene expression b. Increase in gene expression

a. increase in compaction of histones, Removal of acetyl group of histones b. decrease in compaction of histones, acetylation of histone tails, removal of histones from a region

a. A protein that binds to DNA and blocks activation of a small number of genes is a/an b. A protein that binds to DNA and activates transcription of some genes is a/an c. Modification of bases in DNA, usually resulting in inhibition of transcription, results from d. The idea that gene regulation involves multiple factors is called e. Function of ____________ can be modulated by binding of small effector molecules, protein-protein interactions, or covalent modifications.

a. repressor b. activator c. methylation d. combinatorial control e. activators and repressors

Cancer results from cells that divide when they should not. A hallmark of cancer is high levels of DNA methylation in cell genomes. Methylation of which genes is MOST likely to lead to cancerous cell formation?

genes that prevent cell division

What would probably NOT increase the accessibility of the DNA for gene transcription?

methylation of DNA

At which of the following level(s) can gene expression be regulated in eukaryotes?

passage of mRNA through the nuclear membrane, destruction of the mRNA, and rate of protein synthesis

RNA polymerase binds to the

promoter

What protein would not interact with a coactivator?

repressors

Which of the following statements about basal transcription factors is TRUE?

they are essential for transcription and they cannot increase the rate of transcription by themselves

The most efficient control of eukaryotic gene expression is achieved at the level of

transcription initiation.

What level of regulation do eukaryotes possess that prokaryotes do not?

transport of RNA out of the nucleus

The assembly of transcription factors begins

upstream from the transcription start site