Eukaryotic Gene Expression & DNA Technology Study Guide
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
1. In a nucleosome, what is the DNA wrapped around?
a. polymerase molecules
b. ribosomes
c. mRNA
d. histones
e. nucleolus protein
____
2. 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.
____
3. 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.
____
4. 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.
____
5. 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
____
6. Genomic imprinting, DNA methylation, and histone acetylation are all examples of
a. genetic mutation.
b. chromosomal rearrangements.
c. karyotypes.
d. epigenetic inheritance.
e. translocation.
____
7. 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%
____
8. 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
____
9. 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.
____ 10. 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
____ 11. 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
____ 12. 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.
____ 13. 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
____ 14. 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.
____ 15. The Ras protein is involved in ____, and cancer-causing forms of the protein are usually ____.
a.
b.
c.
d.
e.
relaying a signal from a growth factor receptor; hyperactive
DNA replication; nonfunctional
DNA repair; hyperactive
cell-cell adhesion; nonfunctional
cell division; nonfunctional
____ 16. 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
____ 17. Plasmids are important in biotechnology because they are
a. a vehicle for the insertion of foreign genes into bacteria.
b. recognition sites on recombinant DNA strands.
c. surfaces for protein synthesis in eukaryotic recombinants.
d. surfaces for respiratory processes in bacteria.
e. proviruses incorporated into the host DNA.
____ 18. Which enzyme was used to produce the molecule in the figure below?
a.
b.
c.
d.
e.
ligase
transcriptase
a restriction enzyme
RNA polymerase
DNA polymerase
____ 19. What is the enzymatic function of restriction enzymes?
a. to add new nucleotides to the growing strand of DNA
b. to join nucleotides during replication
c. to join nucleotides during transcription
d. to cleave nucleic acids at specific sites
e. to repair breaks in sugar-phosphate backbones
____ 20. What is a cloning vector?
a. an enzyme that cuts DNA into restriction fragments
b. a DNA probe used to locate a particular gene in the genome
c. an agent, such as a plasmid, used to transfer DNA from an in vitro solution into a living
cell
d. the laboratory apparatus used to clone genes
e. the sticky end of a DNA fragment
Use the following information to answer the questions below.
A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a
mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin
and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene.
This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in
nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that
produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four
different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin
and tetracycline, and nutrient broth without antibiotics.
____ 21. The principal problem with inserting an unmodified mammalian gene into a bacterial plasmid, and then
getting that gene expressed in bacteria, is that
a. prokaryotes use a different genetic code from that of eukaryotes.
b. bacteria translate polycistronic messages only.
c. bacteria cannot remove eukaryotic introns.
d. bacterial RNA polymerase cannot make RNA complementary to mammalian DNA.
e. bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible
with mammalian DNA.
____ 22. Yeast cells are frequently used as hosts for cloning because
a. they are easy to grow.
b. they can remove introns from mRNA.
c. they have plasmids.
d. both A and B
e. A, B, and C
____ 23. The polymerase chain reaction is important because it allows us to
a. insert eukaryotic genes into prokaryotic plasmids.
b. incorporate genes into viruses.
c. make DNA from RNA transcripts.
d. make many copies of a targeted segment of DNA.
e. insert regulatory sequences into eukaryotic genes.
____ 24. The polymerase chain reaction (PCR) has been used to amplify DNA from which of the following?
a. fossils
b. fetal cells
c. viruses
d. bacteria
e. all of the above
The following questions refer to the techniques, tools, or substances listed below. Answers may be used once,
more than once, or not at all.
A. restriction enzymes
B. gene cloning
C. DNA ligase
D. gel electrophoresis
E. reverse transcriptase
____ 25. ____ produces multiple identical copies of a gene for basic research or for large-scale production of a gene
product
a. A
b. B
c. C
d. D
e. E
____ 26. ____ separates molecules by movement due to size and electrical charge
a. A
b. B
c. C
d. D
e. E
____ 27. ____ seals the sticky ends of restriction fragments to make recombinant DNA
a. A
b. B
c. C
d. D
e. E
____ 28. ____ is used to make complementary DNA (cDNA) from RNA
a. A
b. B
c. C
d. D
e. E
____ 29. ____ cuts DNA molecules at specific locations
a. A
b. B
c. C
d. D
e. E
____ 30. After being digested with a restriction enzyme, genomic DNA fragments are separated by gel electrophoresis.
Specific fragments can then be identified through the use of a
a. plasmid.
b. restriction enzyme.
c. sticky end.
d. nucleic acid probe.
e. RFLP.
____ 31. The segment of DNA shown in the figure below has restriction sites I and II, which create restriction
fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the
separation and identity of these fragments?
a.
b.
c.
d.
e.
____ 32. Which of these is not one of the procedures used in Southern blotting?
a. electrophoresis
b. hybridization
c. autoradiography
d. restriction fragment preparation
e. DNA microarray assay
____ 33. The completion of the Human Genome Project revealed that the human genome contains fewer genes than
expected, not so many more than simpler organisms. How can this be reconciled with the greater complexity
of humans relative to many other organisms?
a. RNA transcripts of human genes are more likely to undergo alternative splicing.
b. Post-translational processing adds diversity to the resulting polypeptides.
c. Polypeptide domains are combined in a variety of ways.
d. Gene expression patterns in humans are often more complex than those in other
organisms.
e. All of the above are correct.
Use the figure below to answer the following questions. The DNA profiles below represent four different
individuals.
____ 34. Which of the following are probably siblings?
a. A and B
b. A and C
c. A and D
d. C and D
e. B and D
____ 35. Gene therapy
a. has proven to be beneficial to HIV patients.
b. involves replacement of a defective allele in sex cells.
c. cannot be used to correct genetic disorders.
d. had apparent success in treating disorders involving bone marrow cells.
e. is a widely accepted procedure.
____ 36. The most powerful way of increasing the specificity of a DNA profile analysis is to
a. select markers present on the sex chromosomes rather than on the autosomes.
b. analyze each marker by PCR rather than RFLP analysis.
c. increase the number of markers used.
d. repeat the analysis multiple times.
e. analyze DNA obtained from skin cells rather than blood cells.
____ 37. A DNA profile is produced by
a. treating selected segments of DNA with restriction enzymes.
b. electrophoresis of restriction fragments.
c. using a probe to locate specific nucleotide sequences.
d. A and B only
e. A, B, and C
____ 38. Which of the following is (are) involved in embryonic development?
a. cell division
b. cell differentiation
c. morphogenesis
d. A and B only
e. A, B, and C
____ 39. What is the term for the physical processes that give rise to the shape of an organism?
a.
b.
c.
d.
e.
morphogenesis
differentiation
totipotency
pluripotency
mitosis
____ 40. The perpetually embryonic regions of plants responsible for continual growth and formation of new organs
are called the
a. stamens.
b. nurse cells.
c. myoblasts.
d. apical meristems.
e. anchor cells.
____ 41. The process of cellular differentiation is a direct result of
a. differential gene expression.
b. morphogenesis.
c. cell division.
d. apoptosis.
e. differences in cellular genomes.
____ 42. The fact that plants can be cloned from somatic cells demonstrates that
a. differentiated cells retain all the genes of the zygote.
b. genes are lost during differentiation.
c. the differentiated state is normally very unstable.
d. differentiated cells contain masked mRNA.
e. differentiation does not occur in plants.
____ 43. "Nuclear transplantation" refers to a(n)
a. cloning method involving the transfer of a nucleus from a differentiated cell into an
enucleated egg cell or zygote.
b. form of gene therapy involving the transfer of nuclei from a healthy individual to the cells
of a patient with a genetic disorder.
c. method of creating new species by injecting diploid nuclei into diploid zygotes in order to
produce tetraploid embryos.
d. method of gene therapy in which nuclei are isolated from cells of an individual with a
genetic disorder, transfected with recombinant DNA, and reintroduced into the individual's
cells.
e. experimental method involving transferring nuclei from cells of an organism of one
species into cells of an organism from another species, and examining the resulting
phenotype.
____ 44. A cell that remains entirely flexible in its developmental possibilities is said to be
a. differentiated.
b. determined.
c. totipotent.
d. genomically equivalent.
e. epigenetic.
____ 45. Differentiation of cells is not easily reversible because it involves
a. changes in the nucleotide sequence of genes within the genome.
b. changes in chromatin structure that make certain regions of the genome inaccessible.
c. chemical modifications of histones and DNA methylation.
d. B and C only
e. A, B, and C
____ 46. Despite the extensive success that scientists have had in cloning animals, the process is still quite inefficient
and cloned animals often show a variety of defects. This is likely because
a. the epigenetic features of the chromatin in differentiated donor nuclei are not completely
erased in the cloning process.
b. cloned animals only have one parent, and therefore carry a high number of homozygous
mutations in their genomes.
c. cloned animals have fewer genes than other animals, and often lack proteins required for
normal health.
d. the surrogate mothers that give birth to cloned animals tend to neglect cloned animals in
favor of their own biological offspring.
e. scientists usually damage the donor cell nuclei in the process of transplantation.
____ 47. In animals, embryonic stem cells differ from adult stem cells in that
a. embryonic stem cells are totipotent, and adult stem cells are pluripotent.
b. embryonic stem cells are pluripotent, and adult stem cells are totipotent.
c. embryonic stem cells have more genes than adult stem cells.
d. embryonic stem cells have fewer genes than adult stem cells.
e. embryonic stem cells are localized to specific sites within the embryo, whereas adult stem
cells are spread throughout the body.
____ 48. Your brother has just purchased a new plastic model airplane. He places all the parts on the table in
approximately the positions in which they will be located when the model is complete. His actions are
analogous to which process in development?
a. morphogenesis
b. determination
c. induction
d. differentiation
e. pattern formation
____ 49. In vertebrates, programmed cell death is essential for all of the following except
a. normal development of the nervous system.
b. normal operation of the immune system.
c. normal morphogenesis of human feet.
d. normal removal of damaged cells.
e. normal triggering of the signal transduction pathways.
____ 50. The term homeobox refers to
a. a group of genes that determine polarity during development.
b. peptide sequences of 60 amino acids that turn other genes on or off.
c. zones of polarizing activity commonly present during limb formation.
d. a specific nucleotide sequence present within certain genes that regulate development.
e. glycoproteins that assist cells during morphogenetic movements.