A. Enhancer B. Promoter C. Activator D. Repressor E. Terminator

Biology, 7e (Campbell)
Chapter 19: Eukaryotic Genomes: Organization, Regulation,
and Evolution
Chapter Questions
1) The condensed chromosomes observed in mitosis include all of the following structures except
A) nucleosomes.
B) 30-nm fibers.
C) 300-nm fibers.
D) looped domain.
E) ribosomes.
Topic: Concept 19.1
Skill: Knowledge
2) Under the electron microscope, unfolded chromatin resembles "beads on a string." What do the "beads" represent?
A) nucleosomes
B) ribosomes
C) beadosomes
D) molecules of DNA polymerase
E) molecules of RNA polymerase
Topic: Concept 19.1
Skill: Knowledge
3) In a nucleosome, what is the DNA wrapped around?
A) polymerase molecules
B) ribosomes
C) mRNA
D) histones
E) nucleolus protein
Topic: Concept 19.1
Skill: Knowledge
4) Which of the following statements concerning the eukaryotic chromosome is false?
A) It is composed of DNA and protein.
B) The nucleosome is the most basic structural subunit.
C) The number of genes on each chromosome is different in different cell types.
D) It consists of a single linear molecule of double-stranded DNA.
E) Active transcription occurs on euchromatin.
Topic: Concept 19.1
Skill: Comprehension
5) If a cell were unable to produce histone proteins, which of the following would be expected to occur?
A) There would be an increase in the amount of "satellite" DNA produced during centrifugation.
B) The cell's DNA couldn't be packed into its nucleus.
C) Spindle fibers would not form during prophase.
D) Amplification of other genes would compensate for the lack of histones.
E) Pseudogenes would be transcribed to compensate for the decreased protein in the cell.
Topic: Concept 19.1
Skill: Comprehension
6) Which of the following statements about histones is incorrect?
A) Each nucleosome consists of two molecules, each of four types of histone.
B) Histone H1 is not present in the nucleosome bead; instead it is involved in the formation of higher-level chromatin structures.
C) The amino end of each histone extends outward from the nucleosome and is called a "histone tail."
D) Histones are found in mammals, but not in other animals or in plants.
E) The mass of histone in chromatin is approximately equal to the mass of DNA.
Topic: Concept 19.1
Skill: Knowledge
7) Why do histones bind tightly to DNA?
A) Histones are positively charged, and DNA is negatively charged.
B) Histones are negatively charged, and DNA is positively charged.
C) Both histones and DNA are strongly hydrophobic.
D) Histones are covalently linked to the DNA.
E) Histones are highly hydrophobic, and DNA is hydrophilic.
Topic: Concept 19.1
Skill: Comprehension
8) Which of the following represents an order of increasingly higher levels of organization?
A) nucleosome, 30-nm chromatin fiber, looped domain
B) looped domain, 30-nm chromatin fiber, nucleosome
C) looped domain, nucleosome, 30-nm chromatin fiber
D) nucleosome, looped domain, 30-nm chromatin fiber
E) 30-nm chromatin fiber, nucleosome, looped domain
Topic: Concept 19.1
Skill: Knowledge
9) Which of the following statements is true?
A) Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA.
B) Both heterochromatin and euchromatin are found in the cytoplasm.
C) Heterochromatin is highly condensed, whereas euchromatin is less compact.
D) Euchromatin is not transcribed, whereas heterochromatin is transcribed.
E) Only euchromatin is visible under the light microscope.
Topic: Concept 19.1
Skill: Knowledge
10) Which of the following is least related to the others?
A) 30-nm chromatin fiber
B) pseudogenes
C) nucleosomes
D) looped domains
E) histones
Topic: Concept 19.1
Skill: Comprehension
11) In a nucleosome, the DNA is wrapped around
A) polymerase molecules.
B) ribosomes.
C) histones.
D) the nucleolus.
E) satellite DNA.
Topic: Concept 19.1
Skill: Knowledge
12) Muscle cells and nerve cells in one species of animal owe their differences in structure to
A) having different genes.
B) having different chromosomes.
C) using different genetic codes.
D) differential gene expression.
E) having unique ribosomes.
Topic: Concept 19.2
Skill: Comprehension
13) Which of the following mechanisms is (are) used to coordinately control the expression of multiple, related genes in eukaryotic cells?
A) organization of the genes into clusters, with local chromatin structures influencing the expression of all the genes at once
B) each of the genes sharing a common control element, allowing a single activator to turn on their transcription at once, regardless of their location in the genome
C) organizing the genes into large operons, allowing them to be transcribed as a single unit
D) A and B only
E) A, B , and C
Topic: Concept 19.2
Skill: Comprehension
14) In which of the following would you expect to find the most methylation of DNA?
A) tandem arrays for ribosomal genes
B) pseudogenes
C) inactivated mammalian X chromosomes
D) globin genes
E) transposons
Topic: Concept 19.2
Skill: Knowledge
15) If you were to observe the activity of methylated DNA, you would expect it to
A) be replicating.
B) be unwinding in preparation for protein synthesis.
C) have turned off or slowed down the process of transcription.
D) be very active in translation.
E) induce protein synthesis by not allowing repressors to bind to it.
Answer: C
Skill: Knowledge
16) Genomic imprinting, DNA methylation, and histone acetylation are all examples of
A) genetic mutation.
B) chromosomal rearrangements.
C) karyotypes.
D) epigenetic inheritance.
E) translocation.
Skill: Comprehension
17) A eukaryotic gene typically has all of the following features except
A) introns.
B) a promoter.
C) an operator.
D) control elements.
E) a terminator.
Topic: Concept 19.2
Skill: Knowledge
18) Approximately what proportion of the DNA in the human genome codes for proteins or functional RNA?
A) 83%
B) 46%
C) 32%
D) 13%
E) 2%
Topic: Concept 19.2
Skill: Knowledge
19) Two potential devices that eukaryotic cells use to regulate transcription are DNA ______and histone ______.
A) methylation; amplification
B) amplification; methylation
C) acetylation; methylation
D) methylation; acetylation
E) amplification; acetylation
Topic: Concept 19.2
Skill: Knowledge
20) In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of
A) transcription.
B) translation.
C) mRNA stability.
D) mRNA splicing.
E) protein stability.
Topic: Concept 19.2
Skill: Knowledge
21) In eukaryotes, transcription is generally associated with
A) euchromatin only.
B) heterochromatin only.
C) very tightly packed DNA only.
D) highly methylated DNA only.
E) both euchromatin and histone acetylation.
Topic: Concept 19.2
Skill: Comprehension
22) A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all. A likely explanation for the lack of transgene expression in the fifth cell line is that the
A) transgene integrated into a heterochromatic region of the genome.
B) transgene integrated into a euchromatic region of the genome.
C) transgene was mutated during the process of integration into the host cell genome.
D) host cell lacks the enzymes necessary to express the transgene.
E) transgene integrated into a region of the genome characterized by high histone acetylation.
Topic: Concept 19.2
Skill: Application
23) A significant difference between eukaryotes and prokaryotes is that
A) DNA is wound around proteins to form chromatin in eukaryotes, but in prokaryotes the DNA is not associated with proteins.
B) gene expression is largely regulated by transcription in prokaryotes, but not in eukaryotes.
C) prokaryotic genes do not contain introns.
D) noncoding DNA sequences are found in prokaryotes, but not in eukaryotes.
E) prokaryotes have less DNA but more noncoding segments than eukaryotes.
Topic: Concept 19.2
Skill: Knowledge
24) During DNA replication,
A) all methylation of the DNA is lost.
B) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are therefore left uncopied.
C) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication.
D) methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template.
E) methylated DNA is copied in the cytoplasm, and unmethylated DNA in the nucleus.
Topic: Concept 19.2
Skill: Comprehension
25) Eukaryotic cells control gene expression by which of the following mechanisms?
A) histone acetylation of nucleosomes
B) DNA methylation
C) enzyme modification of chromatin structure
D) A and B only
E) A, B, and C
Topic: Concept 19.2
Skill: Knowledge
26) General transcription factors
A) are required for the expression of all protein-encoding genes.
B) bind to other proteins or to a sequence element within the promoter called the TATA box.
C) help RNA polymerase bind to the promoter and begin transcribing.
D) usually only lead to a low level of transcription in the absence of additional proteins called specific transcription factors.
E) all of the above
Topic: Concept 19.2
Skill: Knowledge
The questions below refer to the following terms. Each term may be used once, more than once, or not at all.

A. enhancer
B. promoter
C. activator
D. repressor
E. terminator

27) binds to a site in the DNA far from the promoter to stimulate transcription
Topic: Concept 19.2
Skill: Knowledge
28) can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA
Topic: Concept 19.2
Skill: Knowledge
29) site in the DNA located near the end of the final exon, encoding an RNA sequence that determines the 3' end of the transcript
Topic: Concept 19.2
Skill: Knowledge
30) Steroid hormones produce their effects in cells by
A) activating key enzymes in metabolic pathways.
B) activating translation of certain mRNAs.
C) promoting the degradation of specific mRNAs.
D) binding to intracellular receptors and promoting transcription of specific genes.
E) promoting the formation of looped domains in certain regions of DNA.
Topic: Concept 19.2
Skill: Knowledge
31) The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called
A) RNA interference.
B) RNA obstruction.
C) RNA blocking.
D) RNA targeting.
E) RNA disposal.
Topic: Concept 19.2
Skill: Knowledge
32) Which of the following is least related to the others?
A) cyclins
B) ubiquitin
C) tumor suppression
D) protein degradation
E) proteasomes
Topic: Concept 19.2
Skill: Comprehension
33) Which of the following is not a mechanism whereby a proto-oncogene is converted to an oncogene?
A) methylation of bases
B) point mutation
C) gene transposition
D) gene amplification
E) chromosome translocation
Topic: Concept 19.3
Skill: Knowledge
34) Which of the following statements concerning proto-oncogenes is false?
A) They can code for proteins associated with cell growth.
B) They are similar to oncogenes found in retroviruses.
C) They are produced by somatic mutations induced by carcinogenic substances.
D) They can be involved in producing proteins for cell adhesion.
E) They can code for proteins involved in cell division.
Topic: Concept 19.3
Skill: Knowledge
35) Which of the following is not a characteristic of the product of the p53 gene? It
A) is an activator for other genes.
B) slows down the cell cycle.
C) causes cell death.
D) prevents cells from passing on mutations due to DNA damage.
E) slows down the rate of DNA replication by interfering with the binding of DNA polymerase.
Topic: Concept 19.3
Skill: Knowledge
36) Tumor suppressor genes
A) are frequently overexpressed in cancerous cells.
B) are cancer-causing genes introduced into cells by viruses.
C) can encode proteins that promote DNA repair or cell-cell adhesion.
D) often encode proteins that stimulate the cell cycle.
E) all of the above
Topic: Concept 19.3
Skill: Comprehension
37) Which of the following events is (are) necessary for the production of a malignant tumor?
A) activation of an oncogene in the cell
B) inactivation of tumor-suppressor genes within the cell
C) presence of mutagenic substances within the cell's environment
D) presence of a retrovirus within the cell
E) both A and B
Topic: Concept 19.3
Skill: Comprehension
38) The incidence of cancer increases dramatically with age because
A) the Ras protein is more likely to be hyperactive after age sixty.
B) proteasomes become more active with age.
C) as we age, normal cell division inhibitors cease to function.
D) the longer we live, the more mutations accumulate.
E) tumor-suppressor genes are no longer able to repair damaged DNA.
Topic: Concept 19.3
Skill: Comprehension
39) The Ras protein is involved in ______, and cancer-causing forms of the protein are usually ______.
A) relaying a signal from a growth factor receptor; hyperactive
B) DNA replication; nonfunctional
C) DNA repair; hyperactive
D) cell-cell adhesion; nonfunctional
E) cell division; nonfunctional
Topic: Concept 19.3
Skill: Knowledge
40) A genetic test to detect predisposition to cancer would likely examine the APC gene for ______cancer and the BRCA1 and BRCA2 genes for ______cancer.
A) colorectal; breast
B) lung; breast
C) breast; lung
D) colorectal; lung
E) lung; prostate
Topic: Concept 19.3
Skill: Knowledge
41) Which of the following can contribute to the development of cancer?
A) random spontaneous mutations
B) mutations caused by X-rays
C) transposition
D) A and B only
E) A, B, and C
Topic: Concept 19.3
Skill: Comprehension
42) One of the unique characteristics of retrotransposons is that
A) translation of their RNA transcript produces an enzyme that converts the RNA back to DNA.
B) they are found only in animal cells.
C) once removed from the DNA, the gene segments for an antibody variable region are rejoined to the constant region.
D) they contribute a significant portion of the genetic variability seen within a population of gametes.
E) their amplification is dependent on a concurrent retrovirus infection.
Topic: Concept 19.4
Skill: Comprehension
43) The most prominent component of the DNA in eukaryotic genomes is
A) operons.
B) tandemly repeating DNA.
C) gene regulatory sequences.
D) transposable elements and related sequences.
E) Alu elements.
Topic: Concept 19.4
Skill: Knowledge
44) Which of the following statements concerning transposons is false?
A) Transposons may increase the production of a particular protein.
B) Transposons may prevent the normal functioning of a gene.
C) Transposons may decrease the production of a particular protein.
D) Transposons may reduce the amount of DNA within certain cells.
E) Both A and C are false.
Topic: Concept 19.4
Skill: Knowledge
45) Reverse transcriptase may be present in cells that have not been infected by a retrovirus because of the presence of
A) immunoglobulins.
B) retrotransposons.
C) genomic imprinting.
D) proteasomes.
E) oncogenes.
Topic: Concept 19.4
Skill: Comprehension
The questions below refer to the following terms. Each term may be used once, more than once, or not at all.