Ch14 test file

Chapter 14: The Eukaryotic Genome and Its Expression

TEST FILE QUESTIONS

Multiple Choice

1. Cheetahs are very susceptible to disease because

a. they lack genetic diversity.

b. they have many mutated genes.

c. they have many more regulatory proteins compared to prokaryotes.

d. they have very large genomes compared to prokaryotes.

e. much of their DNA is noncoding.

Textbook Reference: 14.0 Endangered Genomes, p. 306

2. Among eukaryotes, there is _______ relationship between complexity and genome

size.

a. an inverse

b. a direct

c. not always an inverse

d. not always a direct

e. no

Textbook Reference: 14.1 What Are the Characteristics of the Eukaryotic Genome? p.

307

3. A lily, which has 18 times more DNA than a human, codes for _______ proteins.

a. more

b. the same number of

c. fewer

d. 337

e. 6,330


307

4. If it were stretched out, the DNA from a human cell would be _______ in length.

a. 2 mm

b. 2 m

c. 2 km

d. 2 m

e. None of the above


307

5. Human cells have approximately _______ times the amount of DNA found in

prokaryotic cells.

a. 10

b. 100

c. 1,000

d. 10,000

e. 100,000


308

6. In eukaryotic cells, transcription and translation

a. are separated: Translation occurs in the nucleus, and transcription occurs in the

cytoplasm.

b. occur together in the cytosol.

c. occur together in the nucleus.

d. are separated: Translation occurs in the cytoplasm, and transcription occurs in the

nucleus.

e. are separated, except for proteins that bind to the DNA and ribosomes, which are

translated in the nucleus.

Textbook Reference: 14.1 What Are the Characteristics of the Eukaryotic Genome? 308

7. Each human chromosome must have

a. a centromeric sequence.

b. telomeric sequences.

c. an origin of replication.

d. All of the above



308

8. RNA synthesis in eukaryotes occurs

a. solely in mitochondria.

b. primarily in the Golgi apparatus.

c. primarily in the endoplasmic reticulum.

d. primarily in the nucleus.

e. solely in the cytoplasm.


308

9. RNA translation in eukaryotes occurs

a. solely in mitochondria.

b. primarily in the Golgi apparatus.

c. primarily in the endoplasmic reticulum.

d. primarily in the nucleus.

e. solely in the cytoplasm.


308

10. In bacteria, transcription

a. is separate from translation.

b. occurs in the nucleus.

c. is not separate from translation.

d. is the process of synthesizing proteins.

e. is continuous for all genes.


308

11. Caenorhabditis elegans is a

a. yeast.

b. virus.

c. fruit fly.

d. bacterium.

e. roundworm.


308

12. C. elegans has approximately _______ genes.

a. 19,000

b. 6,000

c. 4,200

d. 3,200

e. 370


309

13. The genome size of fruit flies is _______ that of roundworms.

a. about the same as

b. much smaller than

c. much larger than

d. slightly smaller than

e. slightly larger than


309

14. The similarity between the human genome and the genome of the puffer fish indicates

that

a. chromosomal rearrangements account for phenotypic differences.

b. humans and puffer fish have a large amount of repetitive DNA.

c. the complexity of an organism is not determined by genes alone.

d. there are more human mRNAs than human genes.

e. alternative splicing may be a key to the levels of complexity in organisms.


309

15. A striking difference between the yeast genome and that of E. coli is in the number of

genes involved in

a. protein secretion.

b. membrane transport.

c. DNA replication.

d. energy production.

e. metabolism.


309

16. In comparison to a simple roundworm, Drosophila melanogaster (the fruit fly) has

_______ genes.

a. about the same number of

b. fewer

c. many more

d. a few more

e. an unknown number of


310

17. The field of _______ is concerned specifically with the comparison of genome

sequences of different organisms and their related functions.

a. biology

b. genetics

c. cytogenetics

d. comparative genomics

e. All of the above


310

18. Arabidopsis thaliana, or shale crest, is a favorite model organism for study because

a. hundreds can grow and reproduce in a small space.

b. it is easy to manipulate.

c. it has a small amount of repetitive DNA.

d. it has a small genome.

e. All of the above


310

19. Transposable elements can

a. alter transcription of a gene.

b. cause a mutation.

c. cause gene duplication.

d. All of the above



312

20. SINEs and LINEs are both

a. highly repetitive DNA sequences.

b. transposable elements.

c. control sequences.

d. retrotransposons.

e. DNA transposons.


312

21. DNA transposons

a. work by means of reverse transcriptase.

b. are transcribed but not translated.

c. are also called retrotransposons.

d. move to new locations in the genome without replicating.

e. are circular DNA molecules.


312

22. Transposable elements are found in both prokaryotes and eukaryotes. One of the

major differences between the copying of transposable elements in eukaryotes and in

prokaryotes is that in some eukaryotes the elements

a. must be denatured before they can be copied.

b. require an RNA intermediate.

c. are not always copied.

d. do not need an enzyme.



312

23. Which of the following statements about transposons is true?

a. They provide mobile promoters.

b. They alter gene activities.

c. They provide for genetic change when required.

d. They inactivate unnecessary or undesirable genes.

e. They may contribute to genetic variation.


312

24. DNA sequences found in introns provide

a. amino acid sequence information.

b. regulatory information.

c. no known useful information.

d. structure for the gene.

e. alternative DNA splicing possibilities.

Textbook Reference: 14.2 What Are the Characteristics of Eukaryotic Genes? p. 313

25. Exons are

a. spliced out of the original transcript.

b. spliced together from the original transcript.

c. spliced to introns to form the final transcript.

d. much larger than introns.

e. larger than the original coding region.


26. The regions of DNA in a eukaryotic gene that encode a polypeptide product are called

a. enhancers.

b. mRNAs.

c. hnRNAs.

d. exons.

e. leader sequences.


27. Exons are

a. translated.

b. found in most prokaryotic genes.

c. removed during RNA processing.

d. Both a and b

e. Both a and c


28. Which of the following is a promoter?

a. Protein

b. RNA

c. DNA

d. Carbohydrate

e. Enzyme


29. The region of a gene that binds RNA polymerase to initiate transcription is

a. an exon.

b. the consensus sequence.

c. heterochromatin.

d. the cap.

e. the promoter.


30. In eukaryotic cells, promoters are

a. transcribed.

b. transcribed and translated.

c. neither transcribed nor translated.

d. transcribed and then removed.

e. sequences of RNA that are spliced out.


31. Nucleic acid hybridization

a. is used to study the relationship between eukaryotic genes and their transcripts.

b. requires that the original DNA molecule be denatured.

c. involves the use of a probe to form a double-stranded molecule.

d. originally revealed the existence of introns.

e. All of the above

Textbook Reference: 14.2 What Are the Characteristics of Eukaryotic Genes? pp. 313–

314

32. The theoretical basis for DNA–DNA or DNA–RNA hybridization studies is

a. base complementarity between nucleic acid strands.

b. enzyme action.

c. DNA and RNA looping.

d. Both a and c



33. When eukaryotic DNA is hybridized with mRNA, the hybrid molecules contain loops

of double-stranded DNA called

a. retroviruses.

b. introns.

c. exons.

d. transcripts.

e. puffs.


34. A gene family is a set of genes that over time has changed slightly, extensively, or not

at all. Which of the following statements about all gene families is true?

a. They must always be on the same chromosome.

b. They must always code for the exact same proteins.

c. One copy must retain the original function.

d. They usually differ in their exons because these are coding segments.



35. The different members of the -globin gene family

a. are expressed differently in different tissues.

b. are expressed differently at different times of development.

c. are expressed in the same way in different tissues.

d. are expressed in the same way at different times of development.

e. have no known function.


36. A set of related genes that encode similar proteins is a(n)

a. pseudogene.

b. intron.

c. gene family.

d. retrovirus.

e. oncogene.


37. Most gene families probably arose through the process of

a. RNA processing.

b. RNA splicing.

c. DNA methylation.

d. transcriptional regulation.

e. gene duplication.


38. Which of the following statements about the globin genes is true?

a. Different genes are expressed during different stages of prenatal development.

b. Only one copy is functional.

c. The lengths of the mRNAs are very different for different genes.

d. They are the result of differential posttranscriptional splicing.

e. The transcripts are longer than the coding regions.


39. The modified G cap on eukaryotic mRNAs is found

a. at the 5’ end.

b. at the 3’ end.

c. in the consensus sequence.

d. in the poly A tail.

e. in snRNA.

Textbook Reference: 14.3 How Are Eukaryotic Gene Transcripts Processed? p. 316

40. Poly A tails

a. are added after transcription.

b. are encoded by a sequence of thymines in the DNA.

c. are found in all mRNAs.

d. have no function.

e. are removed during RNA processing.


41. A posttranscriptional modification of mRNA found in eukaryotes is the

a. 5’ cap.

b. 3’ cap.

c. poly T tail.

d. polyadenylation at the 5’ end.



42. What are the three processes that must be completed before transcripts can be

translated in eukaryotes?

a. Binding of snRNPs, addition of a poly A tail, splicing of introns

b. Binding of snRNPs, transporting, synthesizing of ribose

c. Capping, transporting, synthesizing of ribose

d. Binding of snRNPs, capping, splicing

e. Splicing, capping, addition of a poly A tail


43. RNA processing in eukaryotes involves the

a. addition of a G cap.

b. addition of a poly A tail.

c. removal of introns.

d. splicing of exons.

e. All of the above


44. Which of the following is not part of RNA processing in eukaryotes?

a. Splicing of exons

b. Reverse transcription

c. Addition of a 5’ cap

d. Addition of a poly A tail

e. Intron removal


45. Chromosomes of eukaryotic DNA must have

a. DNA sequences that make up telomeres and centromeres.

b. proteins that are centromeres and DNA that form telomeres.

c. a 5’ G cap.

d. an inactivation center.



46. The tail added to pre-mRNA is

a. coded for by DNA.

b. composed of poly T.

c. important for mRNA stability.

d. attached to its 5’ end.

e. All of the above


47. The methylated guanosine cap that is added to the 5’ end of primary mRNA

a. contains all of the coding and noncoding sequences of the DNA template.

b. provides the mRNA molecule with a poly A tail.

c. facilitates the binding of mRNA to ribosomes.

d. forms hydrogen bonds.

e. helps transfer amino acids to the ribosomes.


48. Consensus sequences (short segments of DNA) appear in the transcribed regions of

various genes. These sequences appear to be involved in

a. directing the polymerases to the appropriate place on the DNA for transcription to

begin.

b. the splicing of introns out of the DNA.

c. allowing the transcription to stop at the appropriate spot.

d. catalyzing the synthesis of a protein.



49. Energy for RNA splicing comes

a. from the nucleotides in the RNA.

b. from ATP.

c. directly from photosynthesis.

d. from glucose.

e. from the splicing enzyme.


50. The binding of snRNPs to consensus sequences is necessary for

a. gene duplication.

b. the addition of a poly A tail.

c. capping an hnRNA.

d. RNA splicing.

e. transcription.


51. snRNPs are

a. exon–intron boundary regions.

b. small nuclear ribonucleoprotein particles.

c. protein fragments removed from snRNA molecules.

d. signal ribosomal nuclear proteins.

e. glucose-conjugated trapezoids.


52. Which of the following is not a control mechanism for regulating the amount of

protein synthesized in eukaryotic cells?

a. Transcription regulation

b. DNA amplification

c. Transcript processing

d. Breakdown of the synthesized protein

e. Stabilization of the mRNA

Textbook Reference: 14.4 How Is Eukaryotic Gene Transcription Regulated? p. 318

53. Gene expression can be regulated

a. before transcription.

b. during transcription and before translation.

c. during translation.

d. after translation.

e. All of the above


54. Transcription factors are

a. RNA sequences that bind to RNA polymerase.

b. DNA sequences that regulate transcription.

c. proteins that bind to DNA near the promoter sequence.

d. polysaccharides that bind to the transcripts.

e. factors that bind to enhancers.


55. The three RNA polymerases of eukaryotes catalyze _______ synthesis.

a. rRNA

b. mRNA

c. tRNA

d. All of the above



56. RNA polymerase II by itself cannot bind to the chromosome and initiate transcription.

It can bind and act only after regulatory proteins called _______ factors have been

assembled.

a. translation

b. posttranslation

c. initiation

d. transcription


Textbook Reference: 14.4 How Is Eukaryotic Gene Transcription Regulated? 319

57. The RNA polymerase that produces mRNA molecules in eukaryotic cells is

a. RNA polymerase I.

b. RNA polymerase II.

c. RNA polymerase III.

d. primase.

e. reverse transcriptase.


58. Which of the following statements about TATA boxes is false?

a. They bind a specific transcription factor.

b. They are found in the region of the promoter.

c. They are part of the intron consensus sequence.

d. They help specify the starting point for transcription.

e. They contain thymine–adenine base pairs.


59. Transcription of eukaryotic genes requires

a. binding of RNA polymerase to the promoter.

b. binding of several transcription factors.

c. capping of mRNA.

d. Both a and b

e. All of the above


60. The TATA box is a(n)

a. sequence close to the promoter region of many genes.

b. square-shaped sequence.

c. enhancer consensus sequence.

d. activator sequence necessary for proper translation.



61. Which of the following is a transcription factor?

a. Protein

b. RNA

c. DNA

d. Carbohydrate

e. Enzyme


62. Which of the following is not a DNA binding motif?

a. Helix-straight-helix

b. Helix-turn-helix

c. Helix-loop-helix

d. Leucine zipper

e. Zinc finger


63. Which of the following is an enhancer?

a. Protein

b. RNA

c. DNA

d. Carbohydrate

e. Enzyme


64. In eukaryotic cells, a repressor

a. is made of DNA.

b. binds to the enhancer region to block transcription.

c. is located both upstream and downstream from the promoter.

d. binds to the operator to block RNA polymerase.

e. binds to a silencer to reduce transcription rates.


65. When an enhancer is bound, it

a. increases the stability of a specific mRNA.

b. stimulates transcription of a specific gene.

c. stimulates transcription of all genes.

d. stimulates splicing of a specific mRNA.

e. stimulates splicing of all mRNAs.


66. A DNA sequence, which can be distant from the gene, stimulates transcription when

bound by a protein. This sequence is called a(n)

a. TATA box.

b. operon.

c. enhancer.

d. promoter.

e. consensus sequence.


67. Which of the following statements about -globin production is true?

a. A translational repressor protein binds to the -globin and prevents ribosomes from

attaching.

b. Alternative splicing of pre-mRNA results in the production of several different -

globins.

c. Transcription of the -globin gene is determined by transcription factors, regulators,

enhancers, activators, silencers, and repressors.

d. Ubiquitin forms a complex with the -globin that causes its premature breakdown.

e. The 5’ guanosine cap added to the mRNA is the location where RNA polymerase

initiates transcription.


68. Coordinated gene expression in eukaryotic cells is possible because

a. one event often leads to another similar event.

b. a transcript codes for more than one protein.

c. of similarities in promoters for different genes.

d. of the universal nature of the genetic code.

e. all promoters are different.


69. The drought stress response in plants is an example of

a. a transcription factor.

b. coordinated gene expression.

c. a way to increase water intake.

d. Both a and b



70. DNA is wound around histones to form structures that block both the initiation and

elongation steps of transcription. These structures are

a. condensed chromosomes.

b. lampbrush chromosomes.

c. nucleosomes.

d. the solenoid structure of DNA.

e. 30 nm DNA fibers.


71. Several types of histone modification affect gene activation and repression. Cancer

cells are characterized by a greater degree of

a. methylation.

b. phosphorylation.

c. acetylation.

d. interference.

e. deacetylation.


72. Nucleosomes disaggregate to allow transcription and then reaggregate

a. through alternative splicing.

b. by acetylation and deacetylation.

c. through alternation of nucleotides.

d. by attaching ubiquitin.

e. through insertion of nucleotides.


73. A cell that contains three Barr bodies will necessarily have

a. three Y chromosomes.

b. three X chromosomes.

c. four Y chromosomes.

d. four X chromosomes.

e. three nucleoli.


74. DNA methylation in eukaryotic chromosomes involves adding a methyl to the

a. 5’ position of G.

b. 5’ position of C.

c. proteins bound to the DNA.

d. RNA molecules.

e. ribose.


75. One of the genes that is known to be transcribed from the inactive X chromosome is

a. Xist.

b. ZIST.

c. inactivation controller protein.

d. lithozist.

e. methyl-X.


76. Mary Lyon, Liane Russell, and Ernest Beutler discovered

a. the basis of hormone action.

b. X chromosome inactivation.

c. Barr bodies.

d. melanosomes.

e. heterochromatin.


77. The Barr body is evidence for

a. X chromosome inactivation.

b. cell death.

c. ion pumps.

d. posttranslational control of eukaryotic gene expression.



78. If each interphase nucleus in a preparation of normal rat epithelial cells is found to

contain a single Barr body, one can conclude that

a. the cells are in meiotic prophase.

b. all of the chromatin in these cells is inactive.

c. the DNA in these cells has replicated.

d. the cells are not transcribing any genes.

e. the cells came from a female rat.


79. The interphase cells of normal female mammals have a stainable nuclear body called

a Barr body. This body is

a. an inactive X chromosome.

b. made of fat droplets.

c. made of fragments of mRNA.

d. made of extra chromosomal pieces.



80. Heterochromatin

a. contains poly A tails.

b. is rarely transcribed.

c. does not contain any DNA.

d. is not replicated during the S phase.

e. is found only in prokaryotes.


81. In neurons, the globin gene contains many methylated cytosines. The globin gene,

therefore, is

a. expressed only in males.

b. expressed only in females.

c. not expressed.

d. regulated by posttranscriptional control.

e. regulated by posttranslational control.


82. A chemical modification that adds methyl groups to cytosine residues in some genes

acts to

a. enhance transcription.

b. amplify the gene.

c. inactivate the gene.

d. stabilize the mRNA.



83. DNA methylation

a. is a mechanism of gene inactivation.

b. adds methyl groups to cytosine residues in certain genes.

c. inhibits transcription.

d. Both a and b

e. All of the above


84. In fish and frog eggs, _______ increases from 0.2 percent to 68 percent of the total

genomic DNA through selective gene amplification.

a. tRNA

b. rRNA

c. rRNA gene clusters

d. tRNA gene clusters

e. mRNA gene clusters


85. In some cancers, multiple copies of oncogenes are made and transcribed. This is an

example of

a. gene amplification.

b. DNA methylation.

c. posttranscriptional control.

d. RNA splicing.

e. the assembly of a gene family.


86. Expression of some eukaryotic genes can be regulated by translational control. One

advantage of translational control is that it

a. provides a means for rapid change in protein concentrations.

b. prevents synthesis of excess RNA.

c. directs proteins to their proper subcellular location.

d. occurs only in zygotes.

e. degrades proteins that are no longer needed.

Textbook Reference: 14.5 How Is Eukaryotic Gene Expression Regulated After

Transcription? p. 324

87. The expression of some genes can be regulated in part by the pattern of RNA splicing.

This is an example of

a. DNA methylation.

b. transcriptional regulation.

c. catalytic RNA activity.

d. posttranscriptional control.

e. the endosymbiotic theory.



88. Which of the following statements about the production of tropomyosin is true?

a. A translational repressor protein binds to the tropomyosin mRNA and prevents

ribosomes from attaching.

b. Alternative splicing of pre-mRNA results in the production of several different

proteins.

c. Tropomyosin can recognize and bind to tropomyosin pre-mRNA, causing an

acceleration of its breakdown.

d. Ubiquitin forms a complex with the tropomyosin, which causes its breakdown.

e. The 5’ guanosine cap added to the mRNA is not modified until the mRNA and is

needed.



89. Mature mRNA can be edited by

a. the addition of new nucleotides.

b. methylation.

c. alternative splicing.

d. the attachment of ubiquitin.

e. intron removal.



90. Which of the following statements about the control of protein synthesis in tobacco

hornworms is true?

a. A translational repressor protein binds to the mRNA and prevents ribosomes from

attaching.


proteins.

c. Proteins can recognize and bind to mRNA, causing an acceleration of its breakdown.

d. Ubiquitin forms a complex with the mRNA, which causes its breakdown.

e. The 5’ guanosine cap added to the mRNA is not modified until the mRNA is needed.

Textbook Reference: 14.6 How Is Gene Expression Controlled During and After

Translation? p. 326

91. Which of the following statements about the control of ferritin synthesis is true?

a. A translational repressor protein binds to the ferritin mRNA and prevents ribosomes

from attaching.


proteins.

c. Ferritin can recognize and bind to ferritin RNA, causing an acceleration of its

breakdown.

d. Ubiquitin forms a complex with the ferritin, which causes its breakdown.

e. The 5’ guanosine cap added to the mRNA is not modified until the mRNA and is

needed.


Translation? p. 326

92. Transferrin is a protein that transports iron into cells. The iron concentration in a cell

regulates the amount of transferrin protein being made, but it has no effect on the levels

of transferrin mRNA. This is an example of

a. translational control.

b. the function of an enhancer.

c. transcriptional regulation.

d. RNA processing.

e. the function of a promoter.


Translation? p. 326

93. Ubiquitin forms a complex with proteins and then binds with _______, forming a sort

of “molecular chamber of doom.”

a. the extracellular space

b. mitochondria

c. the proteasome

d. lysosomes

e. the Golgi apparatus


Translation? p. 327

94. Some metabolic pathways are regulated in part by changes in the rate of degradation

of key enzymes.

This is an example of

a. operon control.

b. transcriptional control.

c. liquid hybridization.

d. feedback inhibition.

e. posttranslational control.


Translation? p. 327

Fill in the Blank

1. A genome whose protein product and function has been determined is said to be

_______.


307

2. DNA sequences called _______ can replicate and insert themselves into different parts

of the genome.


311

3. Simple sequence repeats, also known as _______, are very short repetitive sequences

scattered through a genome.


311

4. Segments of a gene that are transcribed but do not encode part of the protein product

are called _______.


5. In both prokaryotes and eukaryotes, the _______ is a stretch of DNA to which RNA

polymerase binds to

initiate transcription.


6. DNA sequences present in pre-mRNA but not present in the mature mRNA are

referred to as noncoding base sequences, or _______.


7. A DNA sequence that signals the end of transcription in eukaryotes is called the

_______.


8. Groups of structurally and functionally related genes within a genome are referred to as

_______.


9. A method used to study the relationship between eukaryotic genes and their transcripts

is _______.


10. Members of a gene family that do not make a functional gene product are called

_______.


11. Most _______ are probably duplicate genes that changed so much during evolution

that they no longer function.


12. During human development, different genes are expressed at different times and in

different tissues. This phenomenon is called _______.


13. During RNA splicing, various snRNPs constitute a “splicing machine” called a

_______.


14. The RNA of snRNPs are complementary to _______ sequences located at the intron–

exon boundaries.


15. There are at least three ways in which _______ may be controlled: (1) Genes may be

inactivated; (2) specific genes may be amplified; and (3) specific genes may be selectively

transcribed.

Textbook Reference: 14.4 How Is Eukaryotic Gene Transcription Regulated? pp. 318–324

16. DNA in eukaryotes is wrapped around special proteins to form structures that look

like beads on a string. These structures are called _______.


17. In a stained preparation of epithelial cells from a female mammal, the highly

condensed chromosome observable in interphase nuclei is the inactive X chromosome, or

_______.


18. The gene that codes for an RNAi that binds to Xist RNA at the active X chromosome

is _______.


19. The process of creating more copies of a gene in order to increase its transcription is

called _______.


Diagram

1.–3. Refer to the graph below to answer the questions that follow.

1. From the graph it can be concluded that

a. different globins are expressed at different times.

b. half of all eukaryotic protein-coding genes exist in only one copy.

c. and are pseudogenes that are a result of mutations.

d. protein-coding genes contain noncoding sequences.

e. RNA can be edited to change the encoded protein.


2. The dominant globin(s) found in a 24-week-old fetus

a. is -globin.

b. is -globin.

c. are -globin and -globin, which are present in equal amounts

d. are -, -, and -globin, present in equal amounts

e. cannot be determined.


3. At about 2 weeks after birth,

a. the amount of -globin increases.

b. the amount of -globin decreases.

c. the amounts of -globin and -globin globin increase.

d. -, -, and -globin are present in equal amounts.

e. -globin and -globin are present in equal amounts.


STUDY GUIDE QUESTIONS

Knowledge and Synthesis Questions

1. Eukaryotic chromosomes

a. are circular and contain origins and terminator sequences.

b. are linear and have origins and telomeres.

c. contain coding and noncoding sequences.

d. Both b and c

Textbook Reference: 14.1 What Are the Characteristics of the Eukaryotic Genome? pp.

307–308

2. Model eukaryotic organisms have helped biologists understand

a. genes involved in development.

b. gene families.

c. genes encoding proteins that are essential for all cells.

d. All of the above


308–311

3. Moderately repetitive DNA includes

a. only coding sequences.

b. only noncoding sequences.

c. coding and noncoding sequences.

d. satellites, minisatellites, and microsatellites.


311

4. Transposable genetic elements

a. always affect the cell adversely, because when they move, they inactivate genes.

b. are retroviruses.

c. provide a mechanism for moving genetic material from organelle genomes to the

nuclear genome.

d. always replicate their DNA when they move.


311–312

5. Introns are DNA sequences that

a. code for functional domains in proteins.

b. are removed from pre-mRNA by spliceosomes.

c. allow one gene to make different gene products, depending on which introns are

removed during splicing.

d. Both b and c

Textbook Reference: 14.2 What Are the Characteristics of Eukaryotic Genes? pp. 313–

315

6. Globin genes are

a. introns that are visible using nucleic acid hybridization with DNA and globin mRNA.

b. translationally regulated by excess heme.

c. part of a family of globin genes, with different genes expressed at different times in

development.

d. All of the above

Textbook Reference: 14.2 What are the Characteristics of Eukaryotic Genes? p. 315; 14.5

How Is Eukaryotic Gene Expression Regulated After Translation? p. 326

7. Pre-mRNAs must be processed in the nucleus in order to

a. increase their stability in the cytoplasm.

b. allow RNA polymerase to initiate transcription.

c. permit coding sequences to be joined to adjacent noncoding sequences.

d. facilitate ribosome recognition in preparation for DNA synthesis.


8. Coordinated regulation of genes in eukaryotic cells

a. is the result of positioning the same regulatory sequence in front of each gene.

b. results from all of those genes being under the control of one promoter.

c. occurs because related genes all have the same operons.

d. occurs because enhancers cause DNA to bend.


9. The transcription complex includes _______ and _______.

a. transcription factors; promoters

b. regulator proteins; regulators

c. repressor proteins; silencers

d. Both a and b


10. DNA binding proteins

a. have distinct three-dimensional structures that allow them to bind to the DNA.

b. can be transcription factors.

c. can help condense the DNA in the nucleus.

d. All of the above


11. Chromatin structure must be altered for gene expression to occur because

a. condensed chromatin is replicated but not transcribed.

b. condensed chromatin makes most DNA sequences inaccessible to the transcription

complex.

c. decondensed chromatin has more nucleosomes per DNA molecule.

d. heterochromatin is actively transcribed and euchromatin is not transcribed.


12. When DNA sequences are moved to new sites on a chromosome,

a. new genes can be transcribed.

b. genes can be inactivated.

c. new genes can be created.

d. All of the above


312

13. rRNA gene copies are amplified to

a. ensure that gene expression in somatic cells will continue.

b. make more copies of DNA origins for replication.

c. ensure that there is enough translational machinery for the rapid development of the

embryo.

d. help heterochromatin become more accessible to the transcription complex.


14. Posttranscriptional regulation can include

a. binding of repressor on silencer regions.

b. insertion and alteration of nucleotides.

c. decreasing mRNA stability in the cytoplasm.

d. Both b and c



15. Genes can be inactivated by

a. inaccurate removal of introns.

b. transposable genetic elements.

c. movement of genes to heterochromatic regions of the chromosome.

d. All of the above


312; 14.4 How Is Eukaryotic Gene Transcription Regulated? p. 323; 14.5 How Are

Eukaryotic Genes Processed? p. 317

Application Questions

1. The cells of the lily plant have 18 times more DNA than human cells, yet human DNA

is more complex. Explain this phenomenon.


311

2. When normal cells become transformed into cancer cells, gene regulation and

chromosome stability in those cells is altered. Describe three different ways that cancer

cells are different from normal cells.


312; 14.4 How Is Eukaryotic Gene Transcription Regulated? p. 324; 14.6 How Is Gene

Expression Controlled During and After Translation? p. 327

3. A mutation occurs in the promoter of a eukaryotic gene, eliminating the TATA box.

How will this mutation affect the transcription of this gene?


4. A different mutation eliminates the enhancer sequence on the DNA for this gene. How

will this mutation affect the transcription of this gene?


5. Describe one posttranscriptional regulatory event and one posttranslational regulatory

event that controls the level of gene expression in eukaryotic cells.


Transcription? pp. 324–326; 14.6: How Is Eukaryotic Gene Expression Controlled

During and After Translation? pp. 326–327

ONLINE QUIZ QUESTIONS

1. Regarding genes and gene expression, which of the following is not a difference

between prokaryotes and eukaryotes?

a. Eukaryotic DNA does not contain a TATA box close to the initiation site as does

prokaryotic DNA.

b. In eukaryotes, RNA polymerase requires ‘transcription factors’or initiation.

c. Prokaryotic genes are often grouped together in operons.

d. In eukaryotes, the regulation of several genes at once requires common control

elements in each of the genes.

e. There is a diversity of eukaryotic polymerases that is reflected in the diversity of

eukaryotic promoters.


Transcripton? p. 319

2. The sequence of mRNA can be changed after transcription and splicing by

a. alternative splicing.

b. exsomes.

c. gene amplification.

d. the insertion of new proteins.

e. RNA editing.



3. It has been found that the genomes of humans and Fugu rubripes are similar, yet

humans are much more complex than Fugu rubripes. What can be concluded from this

difference in complexity even though the number and type of genes are similar?

a. Genes alone do not determine the complexity of an organism.

b. Genes play an integral role in determining an organism’s complexity.

c. Humans have small gene families.

d. Fugu rubripes have small gene families.

e. The Fugu rubripes genome contains 177 genes with sequences similar to genes that

also occur in the human genome and are involved in human disease.


307

4. Which statement about RNA splicing is false?

a. It removes introns.

b. It is performed by small nuclear ribonucleoprotein particles (snRNPs).

c. It always removes the same introns.

d. It is directed by consensus sequences.

e. It shortens the RNA molecule.



5. Processing of pre-mRNA to make mRNA involves

a. splicing out exons from the primary transcript.

b. adding a poly-A tail to the 5’ end.

c. adding a G-cap to the 3’ end.

d. the use of splicing to remove coding sequences.

e. using a spliceosome to cut out the introns.


6. The functions of the eukaryotic genome include all of the following except

a. enzymes for general metabolism.

b. cell cycle regulation and DNA replication.

c. fertilization.

d. membrane structure and transport.

e. cell signaling.


309

7. Put the events of eukaryotic transcription and translation in chronological order,

beginning with the first step.

(1) Pre-mRNA is processed and parts are removed to make mRNA.

(2) Ribosomes translate the mRNA into proteins.

(3) mRNA is transported to the cytoplasm.

(4) DNA is used to make pre-mRNA.

a. 1; 4; 3; 2

b. 4; 3; 1; 2

c. 4; 1; 3; 2

d. 4; 1; 2; 3

e. 1; 2; 4; 3


8. Transcription

a. produces only mRNA.

b. uses ribosomes to synthesize DNA.

c. takes place only in prokaryotes.

d. uses triplet codons to make RNA polymerase.

e. is the process of making an RNA copy of DNA.

Section 14.

9. Which of the following are not used in transcriptional regulation in eukaryotes?

a. Enhancers

b. Silencers

c. Transcription factors

d. RNA polymerase subunits

e. Promoters


10. Which of the following statements about heterochromatin is false?

a. Heterochromatin contains more DNA than does euchromatin.

b. Methylated DNA appears to bind certain chromosomal proteins that may be

responsible for heterochromatin formation.

c. Heterochromatin is generally not transcribed.

d. An example of heterochromatin is the inactive X chromosome of mammals.

e. Any genes contained in heterochromatin are inactivated.


11. Which of the following about mRNA translation is false?

a. Most gene products are modified after translation.

b. An mRNA that is capped with an unmodified GTP molecule is always translated.

c. One way to regulate translation is through the G cap.

d. The stability of the mRNA in the cytoplasm can be regulated.

e. An increase in ferritin synthesis is due to an increased rate of mRNA translation.



12. Which of the following statements about eukaryotic protein-coding genes is false?

a. They contain a promoter that binds with an RNA polymerase to begin the transcription

process.

b. They do not require help from another molecule to recognize the promoter.

c. They contain non-coding base sequences called introns.

d. They are single-copy DNA sequences.

e. They form gene families.


13. A Barr body is the result of

a. euchromatin inactivation.

b. inactivation of an entire X chromosome in human females.

c. euchromatin activation.

d. heterochromatin activation.



14. snRNP’s

a. bind to sites in a pre-mRNA at or near the intron-exon boundaries.

b. bind to consensus sequences.

c. splice out exons from pre-mRNA.

d. Both a and b

e. Both b and c


15. Modifications of the ends of the primary RNA transcript of a protein coding gene

include the addition of a

a. 5’ G cap.

b. 3’ G cap.

c. poly A tail to the 5’ end.

d. poly A tail to the 3’ end.

e. Both a and d


16. Transcription factors in eukaryotes

a. first bind to DNA, allowing RNA polymerase to bind.

b. always repress transcription.

c. are identical at every gene.

d. are always bound to DNA.

e. have only helix-loop-helix domains for DNA binding and recognition.


17. All of the following are potential points for the regulation of gene expression except

a. remodeling of chromatin.

b. mRNA stability control.

c. posttranslational control of protein function.

d. DNA replication.

e. processing control.


18. All of the following are structural motifs of eukaryotic transcription factors except

a. helix-loop-helix.

b. leucine spiral.

c. leucine zipper.

d. zinc finger.

e. helix-turn-helix.


19. All of the following are types of sequences found in eukaryotic genomes except

a. cosmids.

b. highly repetitive.

c. moderately repetitive.

d. tranposons.

e. minisatellites.


311

20. All of the following are types of transposons except

a. retrotransposons.

b. DNA transposons.

c. microtransposons.

d. SINEs.

e. LINEs.


311

TEXTBOOK END-OF-CHAPTER QUESTIONS

1. Eukaryotic protein-coding genes differ from their prokaryotic counterparts in that

eukaryotic genes

a. are double-stranded.

b. are present in only a single copy.

c. contain introns.

d. have a promoter.

e. transcribe mRNA.

2. Comparison of the genomes of yeast and bacteria shows that only yeast has many genes

for

a. energy metabolism.

b. cell wall synthesis.

c. intracellular protein targeting.

d. DNA-binding proteins.

e. RNA polymerase.

3. The genomes of the fruit fly and the nematode are similar to that of yeast, except that

the former organisms have many genes for

a. intercellular signaling.

b. synthesis of polysaccharides.

c. cell cycle regulation.

d. intracellular protein targeting.

e. transposable elements.

4. Which of the following does not occur after mRNA is transcribed?

a. Binding of RNA polymerase II to the promoter

d. Splicing out of the introns

e. Transport to the cytosol

5. Which statement about RNA splicing is not true?

a. It removes introns.

b. It is performed by small nuclear ribonucleoprotein particles (snRNPs).

c. It always removes the same introns.

d. It is usually directed by consensus sequences.

e. It shortens the RNA molecule.

6. Eukaryotic transposons

a. always use RNA for replication.

b. are approximately 50 bp long.

c. are made up of either DNA or RNA.

d. do not contain genes coding for transposition.

e. make up about 40 percent of the human genome.

7. Which statement about selective gene transcription in eukaryotes is not true?

a. Different classes of RNA polymerase transcribe different parts of the genome.

b. Transcription requires transcription factors.

c. Genes are transcribed in groups called operons.

d. Both positive and negative regulation occur.

e. Many proteins bind at the promoter.

8. Heterochromatin

a. contains more DNA than does euchromatin.

b. is transcriptionally inactive.

c. is responsible for all negative transcriptional control.

d. clumps the X chromosome in human males.

e. occurs only during mitosis.

9. Translational control

a. is not observed in eukaryotes.

b. is a slower form of regulation than transcriptional control.

c. can be achieved by only one mechanism.

d. requires that mRNA be uncapped.

e. ensures that heme synthesis equals globin synthesis.

10. Control of gene expression in eukaryotes includes all of the following except

a. alternative splicing of RNA transcripts.

b. binding of proteins to DNA.

c. transcription factors.

d. feedback inhibition of enzyme activity by allosteric control.

e. DNA methylation.

ANSWERS

TEST FILE

Multiple Choice

1. a

2. d

3. c

4. b

5. d

6. d

7. d

8. d

9. e

10. c

11. e

12. a

13. c

14. c

15. a

16. b

17. d

18. e

19. d

20. b

21. d

22. c

23. e

24. c

25. b

26. d

27. a

28. c

29. e

30. c

31. d

32. a

33. b

34. c

35. b

36. c

37. e

38. a

39. a

40. a

41. a

42. e

43. e

44. b

45. c

46. c

47. c

48. b

49. b

50. d

51. b

52. d

53. e.

54. c

55. d

56. d

57. b

58. c

59. d

60. a

61. a

62. a

63. c

64. e

65. b

66. c

67. c

68. c

69. b

70. c

71. e

72. b

73. d

74. b

75. a

76. b

77. a

78. e

79. a

80. b

81. c

82. c

83. e

84. c

85. a

86. a

87. d

88. b

89. a

90. e

91. a

92. a

93. c

94. e

Fill in the Blank

1. annotated

2. transposable elements

3. microsatellites

4. introns

5. promoter

6. introns

7. terminator

8. gene families

9. nucleic acid

hybridization

10. pseudogenes

11. pseudogenes

12. differential gene

expression

13. spliceosome

14. consensus

15. transcription

16. nucleosomes

17. Barr body

18. Tsix

19. gene amplification

Diagram

1. a

2. a

3. e

STUDY GUIDE

Knowledge and Synthesis

1. d. Eukaryotic chromosomes are linear, contain origins, telomeres and coding and non

coding sequences. (Prokaryotic chromosomes are circular and contain termination

sequences.)

2. d. Important developmental genes and gene families have been found in several

different eukaryotic organisms. Comparisons of genes in eukaryotes and prokaryotes have

revealed many similar genes that provide the same essential functions to those cells.

3. c. Moderately repetitive sequences include the ribosomal gene clusters as well as

noncoding sequences such as telomeres and Alu sequences. Satellites, minisatellites, and

microsatellites do not contain genes.

4. c. Transposable elements do not always have an adverse effect on genes; sometimes

their insertion can create new genes. Retrotransposons are like retroviruses, but lack the

genes for the viral capsid proteins. DNA transposons do not replicate their DNA before

they move to a different site on the chromosome.

5. d. Introns are removed by spliceosomes, and differential splicing can produce different

gene products as seen in the tropomyosin example (review Figure 14.20).

6. d. The introns in the -globin gene are visible as loops in hybridizations between -

globin DNA and the mRNA for -globin (see Figure 14.6). Globin genes are

translationally regulated by heme, and they are part of the family of globin genes.

7. a. Pre-mRNAs are processed in the nucleus for many reasons (see Figures 14.10 and

14.11), including to increase their stability in the cytoplasm. Transcription by RNA

polymerase precedes pre-mRNA processing. Noncoding sequences (introns) are removed

from the pre-mRNA, not joined to coding sequences (exons). Ribosome recognition does

not lead to DNA synthesis.

8. a. Each eukaryotic gene is transcribed from a separate promoter, and eukaryotic genes

do not have operons to regulate them.

9. d. Transcription complexes include transcription factors bound to the promoter and

regulator proteins bound to regulators. (When repressor proteins are bound to silencers,

transcription is inhibited.)

10. d. DNA binding proteins must have three-dimensional structures appropriate for

binding DNA. Some DNA-binding proteins are transcription factors, some are

telomerases, which bind the ends of chromosomes, and some are nucleosomes, which

bind the DNA and help pack it into the nucleus.

11. b. Nucleosomes condense the DNA. Heterochromatin is transcriptionally inactive,

whereas euchromatin is transcriptionally active.

12. d. Transposable elements can be transcribed if they move adjacent to a promoter.

Transposable elements can inactivate a gene if they insert into the middle of a coding

sequence. Transposable elements can move parts of genes with them to new

chromosomal sites, potentially creating new genes.

13. c. Ribosomal RNA amplification occurs in the eggs of fishes and frogs to prepare for

the rapid development and protein synthesis that immediately follows fertilization.

Amplified rRNA is not needed in somatic cells, DNA origins or for accessibility to the

chromosome.

14. d. Repressors that bind at silencer sequences regulate transcription and thus are not

posttranscriptional mechanisms of regulation.

15. d. Inaccurate removal of introns can create mRNAs that are missing coding sequence

or that have extra noncoding sequences. Transposable genetic elements can move into the

coding regions of genes, inactivating those gene products. Moving a gene to a hetero-

chromatic (transcriptionally inactive) region of a chromosome results in that DNA being

inaccessible to the transcription complex.

Application

1. The DNA of the lily plant must contain more noncoding and repetitive sequences and

less coding sequence than human DNA.

2. Genetic changes can make a normal cell into a cancerous cell in the following ways: a

transposable element can move into the coding sequence of a gene that regulates cell

division, inactivating that gene, amplification of oncogenes can transform normal cells

into cancer cells, targeting proteins that control cell division for proteasome degradation

(as seen in human papilloma virus and p53) will cause cells to become cancerous.

3. If the TATA box of the promoter for a eukaryotic gene is deleted, transcription factor

TFIID will not bind the promoter. The transcription complex will not assemble at the

promoter and there will be no initiation of transcription.

4. If the enhancer for a gene is deleted, transcription for that gene will still occur, but at a

reduced rate.

5. Posttranscriptional regulatory events can include events that affect splicing, mRNA

stability and inhibition of translation by microRNAs. Posttranslational events can include

modifying the G cap so that the mRNA will be translated and protein degraded.

ONLINE QUIZ

1. a

2. e

3. a

4. c

5. e

6. c

7. c

8. e

9. d

10. a

11. b

12. b

13. b

14. d

15. e

16. a

17. d

18. b

19. a

20. c

TEXTBOOK END-OF-CHAPTER

1. c

2. c

3. a

4. a

5. c

6. c

7. c

8. b

9. e

10. d

Ch14 test file

Health & Medicine

Transcript of Ch14 test file