Ch09 test file

Chapter 9: Chromosomes, the Cell Cycle, and Cell Division

TEST FILE QUESTIONS

Multiple Choice

1. HeLa cells, which have been used for more than fifty years in biomedical

research,

a. have led to a cure for certain cancers.

b. can live and multiply outside the body.

c. favor apoptosis over mitosis.

d. are unaffected by viruses.

e. are capable of meiosis.

Textbook Reference: 9.0 The Immortal Cells of Henrietta Lacks, pp. 180–181

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.

Textbook Reference: 9.1 How Do Prokaryotic and Eukaryotic Cells Divide? p. 181

3. In order 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

Textbook Reference: 9.1 How Do Prokaryotic and Eukaryotic Cells Divide? pp.

181–182

4. During bacterial cell division, the two DNA molecules are separated 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.

Textbook Reference: 9.2 How Is Eukaryotic Cell Division Controlled? p. 184

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. The cells of the intestinal epithelium are continually dividing, replacing dead

cells lost from the surface of the intestinal lining. If you examined a 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 cell cycle consists of

a. mitosis and meiosis.

b. G1, the S phase, and G2.

c. prophase, metaphase, anaphase, and telophase.

d. interphase and mitosis.

e. meiosis and fertilization.


15. 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.


16. The initiation of the S phase and the M phase of the cell cycle depends on a pair

of biochemicals called _______ and _______.

a. actin; myosin

b. Cdk’s; cyclin

c. ligand; receptor

d. MSH; MSH-receptor

e. ATP; ATPase


17. When cyclin binds Cdk,

athe 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.


18. Cyclin-dependent kinases (Cdk’s) catalyze the phosphorylation of targeted

proteins, a process that

a. makes the targeted proteins hydrophilic.

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.


19. Regulation of the cell cycle is dependent upon 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.


20. DNA damage by UV radiation causes the synthesis of

a. p53.

b. DNA.

c. Cdk.

d. cyclin.

e. p21.


21. Half of all human cancers have defective _______ associated with their cells.

a. p53

b. p21

c. Cdk

d. cyclin

e. DNA polymerase


22. 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

Textbook Reference: 9.3 What Happens during Mitosis? p. 187

23. Chromosomes contain large amounts of interacting proteins known as

a. pentanes.

b. hexosamines.

c. histones.

d. protein hormones.

e. histamines.


24. The molecules that make up a chromosome are _______ and _______.

a. DNA; RNA

b. DNA; proteins

c. proteins; lipids

d. nucleotides; nucleosides

e. proteins; phospholipids


25. 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.


26. 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.


27. Nucleosomes are composed of _______ and _______.

a. centromeres; DNA

b. microtubules; condensins

c. kinetochores; centromeres

d. histones; DNA

e. polar microtubules; kinetochore microtubules


28. The DNA of a eukaryotic cell is

a. double-stranded.

b. single-stranded.

c. circular.

d. complex inverted.

e. conservative.


29. Around _______ base pairs wrap around each core particle in a _______.

a. 1,000; solenoid

b. 20,000; chromosome

c. 146; nucleosome

d. 1,000; chromosome

e. 20,000; solenoid


30. Interleukins and erythropoietin are

a. growth factors.

b. Cdk’s.

c. cyclins.

d. antitumor agents.

e. intracellular signaling molecules.


31. 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


32. 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.


33. The mitotic spindle is composed of

a. chromosomes.

b. chromatids.

c. microtubules.

d. chromatin.

e. centrosomes.


34. Which of the following does not occur during mitotic prometaphase?

a. Disappearance of the nuclear envelope

b. Initial movement of chromosomes toward the poles

c. Adhesion of chromatids at the centromere

d. Synapsis of homologous chromosomes

e. Disappearance of the nuclei


35. 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.


36. 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.


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. 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.


40. 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.


41. 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


42. During mitotic anaphase, chromatids migrate

a. from the poles of the cell toward the metaphase plate.

b. from the metaphase 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 metaphase plate.


43. 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.


44. At the milestone that defines anaphase, the chromosomes

a. separate.

b. come together.


d. line up.

e. cross over.


45. 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.


46. 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.


47. The spindle checkpoint is a process

a. that is responsible for the breakdown of separase.

b. in which the centromeres separate.

c. that determines whether all kinetochores are attached to the spindle.

d. that makes sure the polar microtubules from each pole overlap.

e. that ensures the attachment of kinetochores to microtubules.


48. Paired chromatids separate and move to opposite poles because

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. centromeres separate.


49. At the milestone that defines telophase, the chromosomes

a. separate.

b. come together.


d. line up.

e. cross over.


50. 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.


51. 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.


52. 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.


53. 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.


54. 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.


55. Genetically diverse offspring result from

a. mitosis.

b. cloning.

c. sexual reproduction.

d. cytokinesis.

e. fission.

Textbook Reference: 9.4 What Is the Role of Cell Division in Sexual Life Cycles? p.

193

56. 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 a lack of variation among the progeny.


193

57. 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.



193

58. 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.


193

59. 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.


193

60. 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.


193

61. All zygotes are

a. multicellular.

b. diploid.

c. animals.

d. clones.

e. gametes.


193

62. 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.


193

63. Diploid cells of the fruit fly Drosophila have ten chromosomes. How many

chromosomes does a Drosophila gamete have?

a. One

b. Two

c. Five

d. Ten

e. Twenty


193

64. 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.


193

65. 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.


193

66. 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


193

67. 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


193

68. 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.


193

69. 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.


194

70. The diagnosis of Down syndrome is made by examining the individual’s

a. spores.

b. karyotype.

c. chromatin.

d. nucleosomes.

e. kinetochores.


195

71. Human males have ____ sex chromosomes.

a. XX

b. XY

c. XO

d. three types of

e. 23


195

72. Meiosis can occur

a. in all organisms.

b. only when an organism is diploid.

c. only in multicellular organisms.

d. only in haploid organisms.

e. only in single-celled organisms.

Textbook Reference: 9.5 What Happens When a Cell Undergoes Meiosis? p. 195

73. During meiosis, the sister chromatids separate during

a. anaphase II.

b. anaphase I.

c. the S phase.

d. synapsis.

e. telophase II.


74. 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.


75. 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.

Textbook Reference: 9.5 What Happens When a Cell Undergoes Meiosis? pp. 197–

198

76. 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


198

77. 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.


78. 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.


79. 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.


80. 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.


81. Accidents during meiosis that can result in trisomies and monosomies are called

a. nondisjunctions.

b. inversions.

c. reciprocal translocations.

d. recombinations.

e. acrocentricities.


82. 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.


83. 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.


84. 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.


85. 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.


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. 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.


89. 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.


90. 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.


201

91. 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.


92. 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.



93. The process of programmed cell death is called

a. necrosis.

b. lysis.

c. apoptosis.

d. cell displacement.

e. cellular suicide.

Textbook Reference: 9.6 How Do Cells Die? p. 202

94. 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


95. 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.


Fill in the Blank 1. The orderly distribution of genetic information occurs in prokaryotic cells by a

process known as _______.


2. The heritable information of the cell is _______.


3. Prokaryotic DNA molecules are packaged by _______ proteins, which associate

with DNA.


4. Bacteria have a short sequence called _______ where DNA synthesis begins.


5. Bacteria have a short sequence called _______ where DNA synthesis ends.


6. When a DNA molecule doubles, a chromosome is then made up of two joined

_______.


7. The process that ensures that only one of each pair of chromosomes is included in

a gamete is _______.


8. The stage of the cell cycle during which DNA replicates is called the _______.


9. The G2 phase always follows _______ phase.


10. The G in G1 and G2 is short for “_______.”


11. In order to divide, cells must be stimulated by external chemical signals called

______.


12. The structure present during mitosis that is composed of two identical DNA

molecules complexed with proteins and joined at the centromere is called a

_______.


13. The process that ensures that genetic information is passed on to a cell’s

daughter cells is _______.


14. The main role of nucleosomes in eukaryotic cells is to _______ the DNA.


15. The milestone event that defines entry into prometaphase is loss of the _______.


16. During prometaphase, the chromatids are held together by _______.


17. The chromatin _______ during prophase.


18. In general, the division of the cell, called _______, follows immediately upon

mitosis.


19. In plants, a _______ forms at the equatorial region of the cell.


20. The cell plate is derived from the _______ of the cell.


21. The “invisible thread” that pinches cells apart during cell division is made of

_______ and _______.


22. A zygote usually has _______ copies of each chromosome.


193

23. A _______ is one of a pair of chromosomes having the same overall genetic

composition and sequence.


193

24. _______ is the fusion of two gametes.


193

25. The _______ is the number, form, and type of chromosomes found in a cell.


26. During prophase I of meiosis, a unique event called _______ results in the

formation of recombinant chromosomes.


27. Occasionally, a homologous chromosome pair fails to separate during anaphase I

of meiosis. One of the resulting cells lacks a copy of this chromosome, whereas the

other contains both members of the homologous pair. These cells are called _______

cells.


28. Nondisjunction causes the production of _______ cells.


29. Down syndrome can be caused by an extra chromosome _______.


30. During a process known as _______, a piece of one chromosome breaks off and

becomes joined to a different chromosome.


31. A cell with three homologous sets of chromosomes is called a _______ cell.


Diagram

1. Refer to the diagram below of a phase of mitosis to answer the question that

follows

Which cell structure is indicated by the two leaders?

a. Chromosome

b. Centromere

c. Chromatid

d. Kinetochore microtubule

e. Centrioles


STUDY GUIDE QUESTIONS Knowledge and Synthesis Questions

1. Which of the following is true of mitosis?


b. DNA replication is completed prior to the beginning of this phase.

c. The chromosome number of the resulting cells is the same as that of the parent

cell.

d. Both b and c

Textbook Reference: 9.3 What Happens during Mitosis? pp. 190–191

2. Which of the following is true of meiosis?


b. DNA replication occurs before meiosis I and

meiosis II.

c. The homologs do not pair during prophase I.

d. The chromosome number of the resulting cells is the same as that of the parent

cell.


3. Which of the following is true of kinetochores on mitotic chromosomes?

a. They are located at the centromere of each chromosome.

b. They are the sites where microtubules attach to separate the chromosomes.

c. They are organized so that there is one per sister chromatid.

d. All of the above


4. Which of the following is true of the mitotic spindle?

a. It is composed of actin and myosin microfilaments.

b. It is composed of kinetochores at the metaphase plate.

c. It is composed of microtubules, which help separate the chromosomes to opposite

poles of the cell.

d. It originates only at the centrioles in the centrosomes.

Textbook Reference: 9.3 What Happens during Mitosis? p.189

5. Imagine that there is a mutation in the Cdk2 gene such that its gene product is

nonfunctional. What kind of effect would this mutation have on a mature red blood

cell?

a. The cell would be unable to replicate its DNA.

b. The cell would not be able to enter G1.

c. The cell would be unable to reproduce itself.

d. There would be no effect, because mature red blood cells do not enter the cell

cycle.

Textbook Reference: 9.2 How is Eukaryotic Cell Division Controlled? p. 186

6. Imagine that there is a mutation in the Cdk2 gene such that its gene product is

nonfunctional. What kind of effect would this mutation have on a mammalian white

blood cell?

a. The cell would be unable to replicate its DNA.

b. The cell would be unable to enter G1.

c. The cell would be unable to reproduce itself.

d. Both a and c


7. Which is true of DNA replication and cytokinesis in Escherichia coli?

a. DNA replication occurs in the nucleus.

b. Cytokinesis is facilitated by microfilaments of actin and myosin.

c. Cell reproduction is initiated by reproductive signals, which result in DNA

replication, DNA segregation, and cytokinesis.

d. The E. coli chromosome is linear.

Textbook Reference: 9.1 How do Prokaryotic and Eukaryotic Cells Divide? p. 182

8. Which of the following is true of chromatids?

a. They are replicated chromosomes still joined together at the centromere.

b. They are identical in mitotic chromosomes.

c. They are identical in meiotic chromosomes.

d. Both a and b


9. Histones are positively charged because

a. the majority of the ions in the nucleus of the cell are negatively charged.

b. histones interact with acidic residues of proteins found in the nucleus.

c. the basic side chains of histone proteins interact with the negatively charged

DNA.

d. histones have a majority of acidic residues in their protein sequence.


10. Chromosome movement during anaphase is the

result of

a. the molecular motors at the kinetochores that move the chromosomes toward the

poles.

b. molecular motors at the centrosome that pull the microtubules toward the poles.

c. shortening of the microtubules at the centrosome that pull the chromosomes

toward the poles.

d. Both a and c

Textbook Reference: 9.3 What Happens during Mitosis? p.190

11. Programmed cell death (apoptosis)

a. occurs in cells that have been deprived of essential nutrients.

b. occurs only in cells that have damaged DNA.

c. is a natural process during development.

d. is signaled by the initiation of mitosis.


12. What would happen to an E. coli cell if the ori site on its chromosome was

deleted?

a. Nothing.

b. Replication would start but could not continue.

c. Replication could not start.

d. The chromosome would be replicated but the cell could not divide.

Textbook Reference: 9.1 How do Prokaryotic and Eukaryotic Cells Divide? p. 182

13. Chiasmata

a. are sites where nonsister chromatids can exchange genetic material during

meiosis.

b. are sites where sister chromatids can exchange genetic material during meiosis.

c. increase genetic variation among the products of meiosis.

d. increase genetic variation among the products of mitosis.

e. Both a and c


14. The difference between asexual and sexual reproduction is

a. asexual reproduction only occurs in bacteria, and sexual reproduction occurs in

plants and animals.

b. asexual reproduction results in an organism that is identical to the parent, whereas

sexual reproduction results in an organism that is not identical to either parent.

c. asexual reproduction results from the fusion of two gametes; sexual reproduction

produces clones of the parent organism.

d. asexual reproduction only occurs in haplontic organisms, and sexual reproduction

occurs only in diplontic organisms.


192

15. A chromatid is

a. one of the pairs of homologous chromosomes.

b. a homologous chromosome.

c. a newly replicated bacterial chromosome.

d. one half of a newly replicated eukaryotic chromosome.


Application Questions

1. How is cell division different in prokaryotic cells and eukaryotic cells?

Textbook Reference: 9.1 How Do Prokaryotic and Eukaryotic Cells Divide? pp 181–

183

2. By administering a drug that inhibits cytokinesis, you have created peaches that

are tetraploid. How many sets of chromosomes do these peaches have? (What is the

ploidy of these chromosomes?) Will these peaches produce gametes that are fertile?

What if the peaches were triploid?

Textbook Reference: 9.5 What Happens When a Cell Undergoes Meiosis? p.199

3. How does cytokinesis differ in animal and plant cells?


4. Describe how two meters of DNA in a typical human cell can fit into the nucleus,

which is 5 µm in diameter.

Textbook Reference: 9.3 What Happens during Mitosis? pp. 187–188, Figure 9.8

5. Describe two ways that the genetic diversity of organisms is increased during

meiosis.


Application Questions

1. How is cell division different in prokaryotic cells and eukaryotic cells?

Textbook Reference: 9.1 How Do Prokaryotic and Eukaryotic Cells Divide? pp 181–

183

2. By administering a drug that inhibits cytokinesis, you have created peaches that

are tetraploid. How many sets of chromosomes do these peaches have? (What is the

ploidy of these chromosomes?) Will these peaches produce gametes that are fertile?

What if the peaches were triploid?

Textbook Reference: 9.5 What Happens When a Cell Undergoes Meiosis? p.199

3. How does cytokinesis differ in animal and plant cells?


4. Describe how two meters of DNA in a typical human cell can fit into the nucleus,

Textbook Reference: 9.3 What Happens during Mitosis? pp. 187–188, Figure 9.8

5. Describe two ways that the genetic diversity of organisms is increased during

meiosis.


ONLINE QUIZ QUESTIONS

1. In sexually reproducing organisms, the diploid phase of the life cycle begins at

a. spore formation.

b. gamete formation.

c. meiosis.

d. mitosis.

e. fertilization.

Textbook Reference: 9.4 What is the Role of Cell Division in Sexual Life Cycles? p.

193

2. Which statement about aneuploidy is false?

a. It results from chromosomal nondisjunction.

b. It does not occur in humans.

c. An individual with an extra chromosome is trisomic.

d. Trisomies are common in human zygotes.

e. A piece of one chromosome may translocate to another chromosome.


and Figure 9.20

3. In human cells, chromosomes are

a. always condensed during the entire cell cycle.

b. different in different tissues.

c. connected by centromeres, except for the X and Y.

d. the same size and length.

e. visible only during mitosis and meiosis.

Textbook Reference: 9.3 What Happens During Mitosis? p. 189

4. Anaphase

a. is the phase when chromosomes move to opposite poles.

b. involves chromosomes lining up at the equatorial plate.

c. occurs before prophase.

d. is not part of mitosis.

e. Both a and c


5. What is the pattern of development in which the gametes are the only haploid

cells in the life cycle, and the mature organism is diploid?

a. Alternation of generation

b. Haplontic life cycle

c. Diplontic life cycle

d. Meiosis

e. Mitosis


193

6. Whether a cell enters the S and M phases of the cell cycle depends on

a. actin and myosin.

b. Cdk’s and cyclins.

c. ligand and receptor.

d. ATP and ATPase.

e. histones and nucleosomes.

Textbook Reference: 9.2 How is Eukaryotic Cell Divison Controlled? p. 184–185

7. Homologous chromosomes cross over during

a. Prophase I.

b. Prophase II.

c. Prophase I and II.

d. Metaphase I.

e. Anaphase II.


8. During meiosis, sister chromatids separate during

a. anaphase I.

b. anaphase II.

c. S phase.

d. synapsis.

e. telophase II.


and Figure 9.16

9. What is the most important difference between meiosis and mitosis?

a. Meiosis is faster than mitosis.

b. Meiosis produces different varieties of cells, whereas mitosis produces identical

daughter cells.

c. Meiosis occurs only in somatic cells, while mitosis occurs in gametic cells.

d. Both a and b

e. Both b and c


and Figure 9.19

10. DNA replication occurs

a. before both mitosis and meiosis.

b. only before mitosis.

c. only before meiosis.

d. during chromosome condensation.

e. during G2.

Textbook Reference: 9.2 How is Eukaryotic Cell Division Controlled? p. 184 and

Figure 9.3

11. Which statement about asexual reproduction is true?

a. In asexual reproduction, the resulting cells are of different sizes.

b. It requires meiosis.

c. In asexual reproduction, there is genetic variation among the offspring.

d. In asexual reproduction, two gametes fuse to produce a zygote.

e. It produces a clone of offspring that is genetically identical to the parent.


193

12. In prophase I of meiosis, the number of chromatids in a cell of a person with

Turner’s syndrome (XO) is

a. 23.

b. 45.

c. 46.

d. 90.

e. 92.


and Figure 9.20

13. Which of the following statements about cell death is false?

a. Cell death can occur because of damage from poisons.

b. Cell death can occur because the cell is no longer needed by the organism.

c. Necrosis is a genetically programmed series of events that results in cell death.

d. Cell death is controlled by signals inside and/or outside the cell.

e. When cell death occurs, the surrounding cells usually ingest the remains of the

dead cells.


14. Interphase involves all of the following steps except

a. DNA replication.

b. the synthesis of cellular components necessary for mitosis.

c. the conservation of energy for later stages of mitosis.

d. the condensation of chromatin.

e. All of the above


15. The chromosome number is reduced in half in meiosis.

a. True

b. False

Textbook Reference: 9.5 What Happens When a Cell Undergoes Meiosos? p. 197

16. Which stage of mitosis includes kinetochore fiber formation?

a. Metaphase

b. Anaphase

c. Telophase

d. Prophase

e. Interphase

Textbook Reference: 9.3 What Happens During Mitosis? p. 189 and Figure 9.9

17. Which of the following events is not a requirement for cell division?

a. Replication of the DNA

b. Cytokinesis

c. Meiosis

d. Receipt of reproductive signal

e. Segregation


18. At the end of mitosis, each daughter cell

a. has twice the DNA and half the cytoplasm of the parent cell.

b. is genetically identical to the parent cell.

c. has half the DNA and half the cytoplasm of the parent cell.

d. has half the cytoplasm and the same amount of DNA as the parent cell.

e. is genetically nonidentical to the parent cell.


19. Mitosis is the process of chromosome separation, while the division of the

cytoplasm is a process known as

a. karyokinesis.

b. cytokinesis.

c. cleavage.

d. splitting.

e. binary fission.

Textbook Reference: 9.3 What Happens During Mitosis? p. 192 and Figure 9.12

20. A human cell in G1 of the cell cycle has 46 (23 pairs) of chromosomes. The

number of daughter chromosomes in telophase II of meiosis is

a. 23.

b. 46.

c. 92.

d. 34.5.

e. 69.


and Figure 9.16

TEXTBOOK END-OF-CHAPTER QUESTIONS

1. Which statement about eukaryotic chromosomes is not true?

a. They sometimes consist of two chromatids.

b. They sometimes consist only of a single chromatid.

c. They normally possess a single centromere.

d. They consist only of proteins.

e. They are clearly visible as defined bodies under the light

microscope.

2. Nucleosomes

a. are made of chromosomes.

b. consist entirely of DNA.

c. consist of DNA wound around a histone core.

d. are present only during mitosis.

e. are present only during prophase.

3. Which statement about the cell cycle is not true?

a. It consists of mitosis and interphase.

b. The cell’s DNA replicates during G1.

c. A cell can remain in G1 for weeks or much longer.

d. DNA is not replicated during G2.

e. Cells enter the cell cycle as a result of internal or external

signals.

4. Which statement about mitosis is not true?

a. A single nucleus gives rise to two identical daughter nuclei.

b. The daughter nuclei are genetically identical to the parent nucleus.

c. The centromeres separate at the onset of anaphase.

d. Homologous chromosomes synapse in prophase.

e. The centrosomes organize the microtubules of the spindle fibers.

5. Which statement about cytokinesis is true?

a. In animals, a cell plate forms.

b. In plants, it is initiated by furrowing of the membrane.

c. It follows mitosis.

d. In plant cells, actin and myosin play an important part.

e. It is the division of the nucleus.

6. Apoptosis

a. occurs in all cells.

b. involves the formation of the plasma membrane.

c. does not occur in an embryo.

d. is a series of programmed events resulting in cell death.

e. is the same as necrosis.

7. In meiosis,

a. meiosis II reduces the chromosome number from diploid

to haploid.

b. DNA replicates between meiosis I and meiosis II.

c. the chromatids that make up a chromosome in meiosis II

are identical.

d. each chromosome in prophase I consists of four chromatids.

e. homologous chromosomes separate from one another in anaphase I.

8. In meiosis,

a. a single nucleus gives rise to two daughter nuclei.

b. the daughter nuclei are genetically identical to the parent nucleus.

c. the centromeres separate at the onset of anaphase I.

d. homologous chromosomes synapse in prophase I.

e. no spindle forms.

9. A plant has a diploid chromosome number of 12. An egg

cell of that plant has 5 chromosomes. The most probable

explanation is

a. normal mitosis.

b. normal meiosis.

c. nondisjunction in meiosis I.

d. nondisjunction in meiosis I and II.

e. nondisjunction in mitosis.

10. The number of daughter chromosomes in a human cell in anaphase II of meiosis

is

a. 2.

b. 23.

c. 46.

d. 69.

e. 92.

ANSWERS

TEST FILE

Multiple Choice

1. b

2. d

3. a

4. d

5. d

6. a

7. d

8. d

9. a

10. c

11. b

12. a

13. a

14. d

15. d

16. b

17. b

18. c

19. d

20. e

21. a

22. c

23. c

24. b

25. e

26. b

27. d

28. a

29. c

30. a

31. a

32. e

33. c

34. d

35. b

36. c

37. b

38. a

39. d

40. e

41. e

42. b

43. d

44. a

45. e

46. b

47. c

48. a

49. c

50. a

51. d

52. e

53. d

54. a

55. c

56. e

57. b

58. d

59. d

60. c

61. b

62. e

63. c

64. a

65. c

66. b

67. b

68. a

69. b

70. b

71. b

72. b

73. a

74. d

75. d

76. e

77. c

78. a

79. c

80. b

81. a

82. d

83. b

84. e

85. b

86. a

87. a

88. c

89. a

90. e

91. b

92. b

93. c

94. a

95. c

Fill in the Blank

1. binary fission

2. DNA

3. basic

4. ori

5. ter

6. chromatids

7. meiosis

8. S phase

9. S

10. gap

11. growth factors

12. chromosome

13. mitosis

14. package

15. nuclear envelope

16. cohesion

17. condenses

18. cytokinesis

19. cell plate

20. Golgi apparatus

21. actin; myosin

22. two

23. homolog

24. Fertilization

25. karyotype

26. crossing over

27. aneuploid

28. aneuploid

29. 21

30. translocation

31. triploid

Diagram

1. d

STUDY GUIDE

Knowledge and Synthesis

1. d. Mitosis occurs after DNA replication and results in cells having the same

number of chromosomes as the parent cell.

2. a. Meiosis occurs after one round of DNA replication. Homologous chromosomes

pair during prophase I of meiosis, and after meiosis II the resulting cells have half

the number of chromosomes as the parent cell.

3. d. Kinetochores, one per sister chromatid, are assembled at the centromere of each

chromosome and are the sites in which microtubules attach to segregate the

chromosomes.

4. c. The mitotic spindle is composed of microtubules, not actin and myosin

filaments. The spindle originates from the centrosome, which may or may not have

centrioles.

5. d. Many cells, such as red blood cells, muscle cells, and nerve cells, lose their

ability to divide as they mature.

6. d. Dividing cells do enter the cell cycle, and cyclin–Cdk complexes signal

transitions in the cell cycle. The cyclin E–Cdk2 complex acts in the middle of G1,

and the cyclin A–Cdk2 complex acts in S1 and stimulates DNA replication. Without

functional Cdk2, no catalytically active cyclin–Cdk complexes can form. The cell

will be unable to replicate its DNA and will not progress through the cell cycle to

reproduce itself.

7. c. Escherichia coli is a prokaryote and lacks a nucleus, has a circular

chromosome, and does not synthesize actin or myosin proteins. Cytokinesis in E.

coli is a result of a reproductive signal that causes the DNA to be replicated and

segregated and, finally, causes the cell to divide.

8. d. Chromatids are highly condensed, newly replicated chromosomes, which will

be segregated to the daughter cells. After DNA replication, chromatids are still

attached to one another at the centromere. Meiotic sister chromatids are different

from one another due to crossing over in prophase of meiosis I. Mitotic sister

chromatids are identical.

9. c. The positive charges on histone proteins are due to the large number of basic

amino acid residues found in these proteins. These positive charges interact with the

negatively charged phosphate sugar backbone of DNA during assembly of the DNA

on the nucleosome.

10. d. Chromosomes are attached to the microtubules at their kinetochores. There

are molecular motors at the kinetochores, which help move the chromosomes to

opposite poles. Chromosomes are also pulled toward the poles by the shortening of

the kinetochore microtubules.

11. c. Programmed cell death occurs during the development of many organisms (for

instance, tadpoles lose their tails to become adult frogs). One of the stimuli for

programmed cell death is DNA damage, but it is not the only cause of death.

Necrosis (cell death that is not programmed) occurs when cells have been deprived

of essential nutrients. The initiation of mitosis is part of the cell cycle, in which cells

reproduce, and is not a step in programmed cell death.

12. c. Without the origin of replication, there would be no site for the replication

proteins to bind to initiate DNA replication, so DNA synthesis would not start.

13. e. Chiasmata are sites where nonsister chromatids

can exchange genetic material during meiosis, which increases genetic variation in

the gametes (the products of meiosis).

14. b. Asexual reproduction produces cells that are identical to the parent and can

occur in plants. Sexual reproduction can occur in haplontic organisms (such as

fungi).

15. d. A chromatid is one half of a newly replicated eukaryotic chromosome, and is

connected to the other (sister) chromatid at the centromere.

Application

1. In most prokaryotic cells there is only one circular chromosome. As the cell

enlarges to prepare for division, the newly replicated daughter chromosomes are

separated at opposite sides of the cell. During fission, the cell membrane pinches in,

and cell wall components are synthesized between the daughter cells. In eukaryotic

cells, there are more chromosomes, and they are linear. The cell undergoes a

sequential set of steps called the cell cycle, in which the chromosomes are replicated

and then separated to opposite poles of the cell. Microtubules are used to segregate

the chromosomes equally into the daughter cells, and actin filaments and myosin

cause the cell membrane to form a contractile ring and separate to form two

daughter cells.

2. Peaches that are tetraploid have four sets of chromosomes. Because there are an

even number of chromosomes (4n), each replicated homologous chromosome will

be able to find a replicated homolog to pair with at meiosis and will produce fertile

gametes. These gametes will be diploid. Triploid cells will not be fertile because one

of the three homologs will not find its pair during prophase of meiosis I, and the

single homologs will be segregated randomly into the daughter cells.

3. In animal cells, cytokinesis results from the interaction of actin filaments and

myosin, which causes the cell membrane to pinch in and divide the cytoplasm into

two cells. In plant cells, a cell plate forms between the newly segregated

chromosomes, and Golgi vesicles fuse at that site to form the new cell membranes.

Cell wall components are then secreted between the plasma membranes to complete

cytokinesis.

4. See Figure 9.8.

5. Genetic diversity is increased during crossing over of prophase I of meiosis so

that each gamete has chromosomes with different combinations of alleles. During

meiosis, each homologous chromosome is randomly segregated to one of the two

poles, resulting 223 different possible combinations of homologous chromosomes per

gamete.

ONLINE QUIZ

1. e

2. b

3. e

4. a

5. c

6. b

7. a

8. b

9. b

10. a

11. e

12. d

13. c

14. d

15. a

16. d

17. d

18. b

19. b

20. b

TEXTBOOK END-OF-CHAPTER

1. d

2. c

3. b

4. d

5. c

6. d

7. e

8. d

9. c

10. c

Ch09 test file

Health & Medicine

Transcript of Ch09 test file