Mastering Biology- BIO 101: Chapter 15

Which of the following regulatory elements is not composed of DNA sequences? a) Promoter-proximal elements b) Enhancers c) Silencers d) Activators

d) Activators

_____ bind(s) to DNA enhancer regions. a) RNA polymerase b) Promoters c) Introns d) Activators e) Exons

d) Activators

Which of the following regulatory DNA sequences might be located thousands of nucleotides away from the transcription start site of a gene? a) TATA box b) Promoter c) Promoter-proximal element d) Enhancer

d) Enhancer

What effect does methylation have on DNA? a) It allows it to be replicated nearly continuously. b) It allows it to be unwound in preparation for protein synthesis. c) It activates transcription. d) It makes it transcriptionally inactive.

d) It makes it transcriptionally inactive.

The operon model of the regulation of gene expression in bacteria was proposed by _____. a) Watson and Crick b) Franklin c) Darwin d) Jacob and Monod e) Mendel

d) Jacob and Monod

Which of the following terms describes the DNA-protein complexes that look like beads on a string? a) Histones b) Chromatin c) 30-nanometer fiber d) Nucleosome

d) Nucleosome

Enzyme complexes that break down protein are called _____. a) lipases b) ubiquitins c) amylase d) proteasomes e) nucleases

d) proteasomes

The nuclear membrane's role in the regulation of gene expression involves _____. a) protein activation b) translation c) protein degradation d) regulating the transport of mRNA to the cytoplasm e)RNA processing

d) regulating the transport of mRNA to the cytoplasm

What is the function of a spliceosome? a) protein activation b) translation c) protein degradation d) regulating the transport of mRNA to the cytoplasm e) RNA processing

e) RNA processing

Which of these indicates an enhancer region? A B C D C and D

A

The diagram below shows a segment of DNA containing an imaginary gene (Z) and the primary RNA transcript that results from the transcription of gene Z. Exons are represented in green and introns are represented in blue. Which of the following choices represent mRNA molecules that could be produced from the primary RNA transcript by alternative RNA splicing? (In each choice, the yellow part on the left represents the 5' cap, and the yellow part on the right represents the poly-A tail.) Select all that apply.

ACEI ACEGI ACGI

Which of these directly bind(s) to the promoter? A B C D C and D

C and D

Which of these is a regulatory gene? A B C D E

D

True or false? One possible way to alter chromatin structure such that genes could be transcribed would be to make histone proteins more positively charged.

False

True or false? Regulatory and basal transcription factors regulate transcription by binding to the promoter.

False

Which statements about the modification of chromatin structure in eukaryotes are true? Select all that apply. a) Acetylation of histone tails in chromatin allows access to DNA for transcription. b) DNA is not transcribed when chromatin is packaged tightly in a condensed form. c) Some forms of chromatin modification can be passed on to future generations of cells. d) Acetylation of histone tails is a reversible process. e) Methylation of histone tails in chromatin can promote condensation of the chromatin. f) Deacetylation of histone tails in chromatin loosens the association between nucleosomes and DNA.

a) Acetylation of histone tails in chromatin allows access to DNA for transcription. b) DNA is not transcribed when chromatin is packaged tightly in a condensed form. c) Some forms of chromatin modification can be passed on to future generations of cells. d) Acetylation of histone tails is a reversible process. e) Methylation of histone tails in chromatin can promote condensation of the chromatin.

Suppose an experimenter becomes proficient with a technique that allows her to move DNA sequences within a prokaryotic genome. If she 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 likely? a) Beta galactosidase will not be produced. b) RNA polymerase will no longer transcribe permease. c) The operon will no longer be inducible. d) The three genes will be expressed normally.

a) Beta galactosidase will not be produced.

Imagine that genes 1, 2, and 4 code for nerve-specific proteins. Which activators would be present in this cell type to ensure transcription of the appropriate genes? a) In nerve cells, the yellow, blue, green, and black activators would have to be present, thus activating transcription of genes 1, 2, and 4. b) In nerve cells, the red and purple activators would have to be present, thus activating transcription of genes 1, 2, and 4. c) In nerve cells, the blue and green activators would have to be present, thus activating transcription of genes 1, 2, and 4. d) None of the activators are needed.

a) In nerve cells, the yellow, blue, green, and black activators would have to be present, thus activating transcription of genes 1, 2, and 4.

Protein-phosphorylating enzymes' role in the regulation of gene expression involves _____. a) protein activation b) translation c) protein degradation d) regulating the transport of mRNA to the cytoplasm e) RNA processing

a) protein activation

In a genome-wide expression study using a DNA microarray assay, what is each spot used to detect? a) the expression of a specific gene by a cell b) the location of a gene within a cell c) the location of a protein produced by a cell d) the fate of proteins produced by a cell

a) the expression of a specific gene by a cell

Regulatory proteins bind to _____. a) the operator c) the lactose-utilization genes c) the regulatory gene d) RNA polymerase e) transcription factors

a) the operator

Which of these is NOT a component of the lac operon? a) lactose-utilization genes only b) promoter only c) regulatory gene only d) operator only e) promoter and operator

c) regulatory gene only

Gene expression can be blocked by a process called RNA interference. Which of the following molecules is involved in this process? a) mRNA b) tRNA c) siRNAs s) rRNAs

c) siRNAs

The diagram below shows two stretches of DNA in the genome of an imaginary eukaryotic cell. The top stretch of DNA includes the fantasin gene, along with its promoter and one of its enhancers. The bottom stretch of DNA includes the imaginin gene, its promoter, and one of its enhancers. The slash marks (//) indicate that more than 1,000 nucleotides separate the promoter and enhancer of each gene. Which statements about the regulation of transcription initiation in these genes are true? Select all that apply. a) Control elements A, B, and C are proximal control elements for the fantasin gene. b) Both the fantasin gene and the imaginin gene will be transcribed at high levels when activators specific for control elements A, B, C, D, and E are present in the cell. c) Control elements C, D, and E are distal control elements for the imaginin gene. d) The imaginin gene will be transcribed at a high level when repressors specific for the imaginin gene are present in the cell. e) The fantasin gene and the imaginin gene have identical enhancers. f) The fantasin gene will be transcribed at a high level when activators specific for control elements A, B, and C are present in the cell. g) Both the fantasin gene and the imaginin gene will be transcribed at high levels whenever general transcription factors are present in the cell.

b) Both the fantasin gene and the imaginin gene will be transcribed at high levels when activators specific for control elements A, B, C, D, and E are present in the cell. c) Control elements C, D, and E are distal control elements for the imaginin gene. f) The fantasin gene will be transcribed at a high level when activators specific for control elements A, B, and C are present in the cell.

Imagine that genes 3 and 5 code for skin specific proteins. Which activators would be present in this cell type to ensure transcription of the appropriate genes? a) In skin cells, the yellow and green activators would have to be present, thus activating genes 3 and 5. b) In skin cells, the red, black, purple, and blue activators would have to be present, thus activating genes 3 and 5. c) In skin cells, the red, purple, and blue activators would have to be present, thus activating genes 3 and 5. d) None of the activators are needed.

b) In skin cells, the red, black, purple, and blue activators would have to be present, thus activating genes 3 and 5.

Which of the following events occurs during DNA replication? a) All methylation of the DNA is lost at the first round of replication. b) Methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylate daughter strands after replication. c) Methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template. d) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are therefore left uncopied.

b) Methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylate daughter strands after replication.

Which of the following events in transcription initiation likely occurs last? a) Regulatory transcription factors bind to enhancers. b) RNA polymerase binds to the promoter of the gene. c) Basal transcription factors form a basal transcription complex. d) TBP is recruited to the promoter.

b) RNA polymerase binds to the promoter of the gene.

Which of the following results can a DNA microarray assay detect or identify? a) They can be used to introduce entire genomes into bacterial cells. b) They allow the expression of many or even all of the genes in a genome to be compared at once. c) They can identify the function of any gene in a genome. d) They allow physical maps of the genome to be assembled in a very short time.

b) They allow the expression of many or even all of the genes in a genome to be compared at once.

Most repressor proteins exhibit allosteric properties. Which of the following molecules binds with the repressor to alter its structure? a) RNA polymerase b) inducer c) transcription factor d) promoter

b) inducer

In the presence of a regulatory protein the lac operon is _____. a) transcribed b) not transcribed c) transcribed at a faster than usual rate d) is turned on e) either transcribed or not transcribed

b) not transcribed

What gene(s) would be transcribed in a cell in which the green, blue, and yellow activators are present? a) gene 4 and gene 1 b) gene 1, gene 2, and gene 4 c) only gene 4 d) None of the genes will be transcribed.

c) only gene 4

Among the newly discovered small noncoding RNAs, one type reestablishes methylation patterns during gamete formation and blocks expression of some transposons. What are these types of RNA called? a) miRNA b) snRNA c) piRNA d) siRNA

c) piRNA