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Chapter 11: The Cell Cycle and Cell Division

1. Which of the following is not true about cervical cancer, which is a relatively common cancer?
a. It can be detected early by a PAP test.
b. It is usually caused by human papillomavirus (HPV).
c. It causes the cervical cells to make peptide E7, which disrupts the cell cycle.
d. It spreads by blocking the retinoblastoma protein RB.
e. It usually remains localized.
2. A bacterial cell gives rise to two genetically identical daughter cells by a process known as
a. nondisjunction.
b. mitosis.
c. meiosis.
d. fission.
e. fertilization.
3. For a prokaryote cell to divide, which of the following must occur?
a. A reproductive signal, replication, segregation of DNA, and cytokinesis
b. DNA replication, crossing over, and segregation of DNA
c. DNA replication and segregation of DNA
d. Cell growth and cytokinesis
e. DNA replication, segregation of DNA, and cytokinesis
4. During the bacterial cell division, the single cells is separated into two cells by
a. centrosomes.
b. spindle fibers.
c. nucleosomes.
d. pinching of the plasma membrane.
e. aneuploidy.
5. During prokaryotic cell division, two chromosomes separate from each other and distribute into the daughter cells by
a. attachment to microtubules.
b. a mitotic spindle.
c. repellent forces.
d. attachment to separating membrane regions.
e. All of the above
6. Bacteria typically have _______, whereas eukaryotes have _______.
a. one chromosome that is circular; many chromosomes that are linear
b. several chromosomes that are circular; many chromosomes that are linear
c. one chromosome that is linear; many chromosomes that are circular
d. two chromosomes that are circular; eight chromosomes that are linear
e. None of the above
7. Which of the following statements about mitosis is true?
a. The chromosome number in the resulting cells is halved.
b. DNA replication is completed in prophase.
c. Crossing over occurs during prophase.
d. Two genetically identical daughter cells are formed.
e. It consists of two nuclear divisions.
8. DNA replication occurs
a. during both mitosis and meiosis.
b. only during mitosis.
c. only during meiosis.
d. during the S phase.
e. during G2.
9. Mature nerve cells, which are incapable of cell division, are most likely in
a. G1.
b. the S phase.
c. G2.
d. mitosis.
e. meiosis.
10. A set of cells in the intestinal epithelium divide continually to replace dead cells lost from the surface of the intestinal lining. If you examined this continually dividing population of intestinal epithelial cells under the microscope, most of the cells would
a. be in meiosis.
b. be in mitosis.
c. be in interphase.
d. have condensed chromatin.
e. Both b and d
11. Cells that do not divide are usually arrested in
a. S.
b. G1.
c. G2.
d. M.
e. prophase.
12. Which of the following phases of the cell cycle is not part of interphase?
a. M
b. S
c. G1
d. G2
e. G0
13. How does a nucleus in G2 differ from a nucleus in G1?
a. The G2 nucleus has double the amount of DNA as the G1 nucleus.
b. DNA synthesis occurs only in the G1 phase.
c. Inactive cells are arrested only in the G2 phase.
d. During G2, the cell prepares for S phase.
e. All of the above
14. A typical cell cycle consists of
a. mitosis and meiosis.
b. G1, the S phase, and G2.
c. prophase, metaphase, anaphase, and telophase.
d. interphase, mitosis, and cytokinesis.
e. meiosis and fertilization.
15. Regulation of the cell cycle is dependent on cyclins and cyclin-dependent kinases. The key(s) that allows a cell to progress beyond the restriction point is (are)
a. Cdk1 and cyclin B.
b. cyclin D and p21.
c. cyclin A and Cdk2.
d. phosphorylation of RB by Cdk4 and Cdk2.
e. external signals from growth factors.
16. Evidence from yeast suggests that the maturation-promoting factor of sea urchins is
a. a cyclin.
b. MFP.
c. an S nuclease.
d. a Cdk.
e. a Cdk/cyclin phosphatase.
17. The initiation of the S phase and the M phase of the cell cycle depends on a pair of molecules called _______ and _______.
a. actin; myosin
b. Cdk's; cyclin
c. ligand; receptor
d. MSH; MSH-receptor
e. ATP; ATPase
18. When cyclin binds Cdk,
a. the cell transitions from G2 to S.
b. kinase activation occurs.
c. chromosomes condense.
d. the cell quickly enters M phase.
e. the cell begins apoptosis.
19. Cyclin-dependent kinases (Cdk's) catalyze the phosphorylation of targeted proteins, a process that
a. decreases the mass of the protein.
b. makes the targeted proteins hydrophobic.
c. changes the shape and function of the targeted proteins.
d. gives the proteins a three-dimensional shape.
e. blocks the cell cycle from proceeding.
20. DNA damage by UV radiation causes the synthesis of
a. p53.
b. DNA.
c. Cdk.
d. cyclin.
e. p21.
21. Interleukins and erythropoietin are
a. growth factors.
b. Cdk's.
c. cyclins.
d. antitumor agents.
e. intracellular signaling molecules.
22. The DNA of a eukaryotic cell is
a. double-stranded.
b. single-stranded.
c. circular.
d. complex inverted.
e. conservative.
23. The uncondensed length of human DNA found in chromosomes is _______, whereas a typical cell is 10 µm in length.
a. 5 µm
b. 2 µm
c. 2 meters
d. 20 meters
e. 2.54 inches
24. Chromosomes contain large amounts of interacting proteins known as
a. pentanes.
b. hexosamines.
c. histones.
d. protein hormones.
e. histamines.
25. The molecules that make up a chromosome are _______ and _______.
b. DNA; proteins
c. proteins; lipids
d. nucleotides; nucleosides
e. proteins; phospholipids
26. The basic structure of chromatin has sometimes been referred to as beads on a string of DNA. These beads are called
a. chromosomes.
b. chromatids.
c. supercoils.
d. interphases.
e. nucleosomes.
27. Chromatin consists of
a. DNA and histones.
b. DNA, histones, and many other nonhistone proteins.
c. mostly RNA and DNA.
d. RNA, DNA, and nonhistone proteins.
e. DNA only.
28. Nucleosomes contain _______ and _______.
a. centromeres; DNA
b. microtubules; condensins
c. kinetochores; centromeres
d. histones; DNA
e. polar microtubules; kinetochore microtubules
29. During mitosis and meiosis the chromatin compacts. Which of the following processes takes place more easily because of this compaction?
a. The orderly distribution of genetic material to two new nuclei
b. The replication of the DNA
c. Exposing the genetic information on the DNA
d. The unwinding of DNA from around the histones
e. The disappearance of the nuclear membrane
30. The products of mitosis are
a. one nucleus containing twice as much DNA as the parent nucleus.
b. two genetically identical cells.
c. four nuclei containing half as much DNA as the parent nucleus.
d. four genetically identical nuclei.
e. two genetically identical nuclei.
31. The mitotic spindle is composed of
a. chromosomes.
b. chromatids.
c. microtubules.
d. chromatin.
e. centrosomes.
32. Centrosomes
a. are constricted regions of phase chromosomes.
b. determine the plane of cell division.
c. are the central region of the cell.
d. are the region where the membrane constricts during cytokinesis.
e. are part of cilia.
33. When dividing cells are examined under a light microscope, chromosomes first become visible during
a. interphase.
b. the S phase.
c. prophase.
d. G1.
e. G2.
34. Chromatin condenses to form discrete, visible chromosomes
a. early in G1.
b. during S.
c. during telophase.
d. during prophase.
e. at the end of cytokinesis.
35. Microtubules that form the mitotic spindle tend to originate from or terminate in
a. centromeres and telomeres.
b. euchromatin.
c. centrioles and telomeres.
d. the nuclear envelope.
e. centrioles and kinetochores.
36. Which of the following does not occur during mitotic prometaphase?
a. Disappearance of the nuclear envelope
b. Initial movement of chromosomes toward the equatorial plate
c. Adhesion of chromatids at the centromere
d. Synapsis of homologous chromosomes
e. Disappearance of the nuclei
37. The structures that line up the chromatids on the equatorial plate during metaphase are called
a. asters.
b. polar and kinetochore microtubules.
c. centrosomes.
d. centrioles.
e. histones.
38. The microtubules of the mitotic spindle attach to a specialized structure in the centromere region of each chromosome called the
a. kinetochore.
b. nucleosome.
c. equatorial plate.
d. aster.
e. centrosome.
39. During mitotic anaphase, chromosomes migrate
a. from the poles of the cell toward the equatorial plate.
b. from the equatorial plate toward the poles.
c. toward the nuclear envelope.
d. along with their sister chromatids toward one pole.
e. along with the other member of the homologous pair toward the equatorial plate.
40. At the milestone that defines metaphase, the chromosomes
a. separate.
b. come together.
c. are at opposite poles.
d. line up at the equatorial plate.
e. cross over.
41. At the milestone that defines anaphase, the chromosomes
a. separate.
b. come together.
c. are at opposite poles.
d. line up.
e. cross over.
42. The energy to move chromosomes during mitosis is provided by
a. centrioles.
b. DNA polymerization.
c. migration of the centrosomes.
d. formation of the cell plate.
e. ATP.
43. Which of the following is not involved in the separation of paired chromatids and their movement to opposite poles?
a. Sister chromatids attach to microtubules in opposite halves of the spindle.
b. Separase hydrolyzes cohesion, allowing chromatid separation.
c. Tubulin fibers move the chromatids away from the equatorial plate.
d. Polar microtubules push the chromatids to the poles.
e. ATP is hydrolyzed by cytoplasmic dynein.
44. At the milestone that defines telophase, the chromosomes
a. separate.
b. come together.
c. are at opposite poles.
d. line up.
e. cross over.
45. Chromosomes "decondense" into diffuse chromatin
a. at the end of telophase.
b. at the beginning of prophase.
c. at the end of interphase.
d. at the end of metaphase.
e. only in dying cells.
46. After the centromeres separate during mitosis, the chromatids, now called _______, move toward opposite poles of the spindle.
a. centrosomes
b. kinetochores
c. half-spindles
d. asters
e. daughter chromosomes
47. In plant cells, cytokinesis is accomplished by the formation of a(n)
a. aster.
b. membrane furrow.
c. equatorial plate.
d. cell plate.
e. spindle.
48. The event in the cell division process that clearly involves microfilaments is
a. chromosome separation during anaphase.
b. movement of chromosomes to the metaphase plate.
c. chromosome condensation during prophase.
d. disappearance of the nuclear envelope during prophase.
e. cytokinesis in animal cells.
49. Which of the following statements about plant cytokinesis is true?
a. It begins when telophase ends.
b. A division furrow completely separates the cytoplasm.
c. It is under the control of Ca2+.
d. Vesicles fuse to form a cell plate.
e. The spindle fibers break down to form a cell plate.
50. The distribution of mitochondria between the daughter cells during cytokinesis
a. is random.
b. is directed by the mitotic spindle.
c. is directed by the centrioles.
d. results in the mitochondria remaining in the parent cell.
e. occurs only during meiosis.
51. A mechanism for increasing the genetic diversity of offspring is
a. mitosis.
b. cloning.
c. sexual reproduction.
d. cytokinesis.
e. fission.
52. The major drawback of asexual reproduction is that it
a. takes a great deal of time.
b. generates variation.
c. prevents change.
d. requires cytokinesis.
e. produces less variation among offspring than does sexual reproduction.
53. During asexual reproduction, the genetic material of the parent is passed on to the offspring by
a. homologous pairing.
b. meiosis and fertilization.
c. mitosis and cytokinesis.
d. karyotyping.
e. chiasmata.
54. A haploid cell is a cell
a. in which the genes are arranged haphazardly.
b. containing only one copy of each chromosome.
c. that has resulted from the process of mitosis.
d. with twice the number of chromosomes of a diploid cell.
e. None of the above
55. All zygotes are
a. multicellular.
b. diploid.
c. animals.
d. clones.
e. gametes.
56. In all sexually reproducing organisms, the diploid phase of the life cycle begins at
a. spore formation.
b. gamete formation.
c. meiosis.
d. mitosis.
e. fertilization.
57. The members of a homologous pair of chromosomes
a. are identical in size and appearance.
b. contain identical genetic information.
c. separate to opposite poles of the cell during mitosis.
d. are found only in haploid cells.
e. are present only after the S phase.
58. Asexual reproduction produces genetically identical individuals because
a. chromosomes do not have to replicate during asexual reproduction.
b. it involves chromosome replication without cytokinesis.
c. no meiosis or fertilization take place.
d. cell division occurs only in meiosis.
e. the mitotic spindle prevents nondisjunction.
59. Each diploid cell of a human female contains _______ of each type of chromosome.
a. one
b. two
c. four
d. a total of 23
e. a total of 46
60. Sexual reproduction increases genetic variability through
a. the exchange of genetic information between male and female gametes during meiosis I.
b. the random separation of homologous chromosomes.
c. the union of male and female gametes.
d. crossing over, independent assortment, and random fertilization.
e. random assortment of male and female chromosomes.
61. In a haploid organism, most mitosis occurs
a. after fertilization and before meiosis.
b. after meiosis and before fertilization.
c. between meiosis I and II.
d. during G1.
e. in diploid cells.
62. The sizes and shapes of chromosomes can be observed most easily in a cell that is in
a. prophase.
b. metaphase.
c. anaphase.
d. telophase.
e. cytokinesis.
63. The diagnosis of Down syndrome is made by examining the individual's
a. spores.
b. karyotype.
c. chromatin.
d. nucleosomes.
e. kinetochores.
64. Human males have _______ sex chromosomes.
a. XX
b. XY
c. XO
d. three types of
e. 23
65. Diploid cells of the fruit fly Drosophila have ten chromosomes. How many chromosomes does a Drosophila gamete have?
a. 1
b. 2
c. 5
d. 10
e. 20
66. The second meiotic division of meiosis is important because
a. it returns the chromosome number to diploid before fertilization.
b. it allows for crossing over and random distribution of chromosomes.
c. it reduces cell size by dividing the cytoplasm in half.
d. without this division, chromosome copies would double at each fertilization.
e. fertilization requires this step.
67. Meiosis can occur
a. in all sexually reproducing organisms.
b. only when an organism is diploid.
c. only in multicellular organisms.
d. only in haploid organisms.
e. only in single-celled organisms.
68. Which of the following is not part of sexual reproduction?
a. The segregation of homologous chromosomes during gamete formation
b. The fusion of sister chromatids during fertilization
c. The fusion of haploid cells from a diploid zygote
d. The reduction in chromosome number during meiosis
e. The production of genetically distinct gametes during meiosis
69. Which of the following statements about homologous chromosome pairs is false?
a. They come from only one of the individual's parents.
b. They usually contain slightly different versions of the same genetic information.
c. They separate from each other during meiosis I.
d. They synapse during meiosis I.
e. Each contains two sister chromatids at the beginning of meiosis I.
70. During meiosis, the sister chromatids separate during
a. anaphase II.
b. anaphase I.
c. the S phase.
d. synapsis.
e. telophase II.
71. At the end of the first meiotic division, each chromosome consists of
a. chiasmata.
b. a homologous chromosome pair.
c. four copies of each DNA molecule.
d. two chromatids.
e. a pair of polar microtubules.
72. Which of the following statements about sister chromatids is false?
a. They arise by replication during S phase.
b. They separate from each other during each mitotic anaphase.
c. They usually contain identical versions of the same genetic information.
d. They separate from each other during meiosis I.
e. They are joined during prophase I and metaphase I at their common centromere.
73. The processes of synapsis and the formation of chiasmata
a. involve reciprocal exchange of chromosomal sections.
b. involve the recombination of DNA on homologous chromosomes.
c. bring about an increase in genetic variation.
d. provide evidence that an exchange of genetic material has occurred.
e. All of the above
74. The exchange of genetic material between chromatids on homologous chromosomes occurs during
a. interphase.
b. mitosis and meiosis.
c. prophase I.
d. anaphase I.
e. anaphase II.
75. The number of chromosomes is reduced to half during
a. anaphase of mitosis and meiosis.
b. meiosis II.
c. meiosis I.
d. fertilization.
e. interphase.
76. The total DNA content of each daughter cell is reduced during meiosis because
a. chromosomes do not replicate during the interphase preceding meiosis I.
b. chromosomes do not replicate between meiosis I and II.
c. half of the chromosomes from each gamete are lost during fertilization.
d. sister chromatids separate during anaphase of meiosis I.
e. chromosome arms are lost during crossing over.
77. Chromosome number is reduced during meiosis because the process consists of
a. two cell divisions without any chromosome replication.
b. a single cell division without any chromosome replication.
c. two cell divisions in which half of the chromosomes are destroyed.
d. two cell divisions and only a single round of chromosome replication.
e. four cell divisions with no chromosome replication.
78. The four haploid nuclei found at the end of meiosis differ from one another in their exact genetic composition. Some of this difference is the result of
a. cytokinesis.
b. replication of DNA during the S phase.
c. separation of sister chromatids at anaphase II.
d. spindle formation.
e. crossing over during prophase I.
79. During meiosis I in humans, one of the daughter cells receives
a. only maternal chromosomes.
b. a mixture of maternal and paternal chromosomes.
c. the same number of chromosomes as that of a diploid cell.
d. a sister chromatid from each chromosome.
e. one-fourth the amount of DNA in the parent nucleus.
80. One difference between mitosis and meiosis I is that
a. homologous chromosome pairs synapse during mitosis.
b. chromosomes do not replicate in the interphase preceding meiosis.
c. homologous chromosome pairs synapse during meiosis but not during mitosis.
d. spindles composed of microtubules are not required during meiosis.
e. sister chromatids separate during meiosis but not during mitosis.
81. A triploid nucleus cannot undergo meiosis because
a. the DNA cannot replicate.
b. not all of the chromosomes can form homologous pairs.
c. the sister chromatids cannot separate.
d. cytokinesis cannot occur.
e. a cell plate cannot form.
82. Genetic recombination occurs during
a. prophase of meiosis I.
b. the interphase preceding meiosis II.
c. the mitotic telophase.
d. fertilization.
e. the formation of somatic cells.
83. How does mitotic prophase differ from prophase I of meiosis?
a. Chromatin supercoils only in mitotic prophase.
b. The nuclear envelope disappears only in prophase I of meiosis.
c. Synapsis occurs in mitotic prophase and but not in meiotic prophase I.
d. The chromatids separate in mitotic prophase, not in prophase I of meiosis.
e. Crossing over is characteristic of prophase I of meiosis but not of mitotic prophase.
84. Accidents during meiosis that can result in trisomies and monosomies are called
a. nondisjunctions.
b. inversions.
c. reciprocal translocations.
d. recombinations.
e. acrocentricities.
85. A potato has a diploid number of 48. If an egg of this plant has 23 chromosomes, the most likely explanation is that
a. normal meiosis has occurred.
b. nondisjunction occurred during meiosis I.
c. normal mitosis has occurred.
d. nondisjunction occurred during mitosis.
e. crossing over occurred during meiosis I.
86. The fact that most monosomies and trisomies are lethal to human embryos illustrates the
a. importance of the orderly distribution of genetic material during meiosis.
b. exchange of genetic information during crossing over.
c. advantage of sexual reproduction to the survival of a population.
d. fact that each chromosome contains a single molecule of DNA.
e. formation of haploid gametes as a result of meiosis.
87. A person with Klinefelter syndrome has 44 chromosomes and three sex chromosomes (XXY). The resulting aneuploidy is caused by
a. nondisjunction.
b. crossing over.
c. a mutation.
d. an enzyme deficiency.
e. failure of DNA to replicate.
88. Many chromosome abnormalities (trisomies and monosomies) are not observed in the human population because
a. they are lethal and cause spontaneous abortion of the embryo early in development.
b. all trisomies and monosomies are lethal early in childhood.
c. meiosis distributes chromosomes to daughter cells with great precision.
d. they are so difficult to count.
e. the human meiotic spindle is self-correcting.
89. A triploid plant has
a. one extra chromosome.
b. one extra set of chromosomes.
c. three chromosomes.
d. three times the chance of surviving that a monoploid has.
e. None of the above
90. The process of programmed cell death is called
a. necrosis.
b. lysis.
c. apoptosis.
d. cell displacement.
e. cellular suicide.
91. Which of the following statements about necrosis is true?
a. It requires ATP.
b. It does not cause inflammation.
c. It may occur when cells are damaged by toxins.
d. It produces nucleosome-sized pieces of chromatin.
e. It results in fragmentation of the cell.
92. An indicator of programmed cell death is
a. fragmented chromatin.
b. swelling of the membrane.
c. cell lysis.
d. loss of transcription control.
e. All of the above
93. Which of the following is true of benign tumors?
a. The cells do not resemble the cells of the parent tissue.
b. The cells of the tumor are often irregular, with nuclei of various sizes and shapes.
c. The cells grow more rapidly than the cells surrounding it.
d. They often metastasize.
e. They are not cancer.
94. One-fourth of all human breast cancers have been found to have an increased amount of the oncogene
a. P21.
b. HER2.
c. Cdk.
d. Cyclin.
e. RB.
95. Knowledge of the cell cycle has led to improved means of treating cancer. The drug 5-fluorouracil blocks the synthesis of thymine. This drugs inhibits the cell cycle at the end of
a. G1.
b. G2.
c. S.
d. prophase.
e. metaphase.
96. Knowledge of the cell cycle has led to improved means of treating cancer. Taxol prevents the microtubules of the spindle fiber from functioning normally. Taxol prevents the cell cycle from entering
a. G1.
b. G2.
c. S.
d. prophase.
e. interphase.
97. High-energy radiation is often used to treat cancer. The radiation kills the cancerous cells, and the cell cycle checkpoint for DNA repair is overwhelmed. Radiation
a. causes apoptosis at the S and G2 checkpoints.
b. inhibits the growth factor at the restriction point.
c. blocks DNA replication.
d. only causes apoptosis at the tumor site.
e. kills all tumor cells without harm to healthy cells.