Deck 11: The Cell Cycle and Cell Division

Question 1

A tissue in a mouse contains two types of cells: one that divides rapidly and one that divides more slowly.The most likely difference between these two cell types is that the slow-dividing cell type spends more time in _______ phase.

A) G1
B) G2
C) G3
D) M
E) S

Answer 1

A

Question 2

If a bacterial colony is grown in a medium that is rich in the amino acid lysine, cell division proceeds rapidly and the colony grows steadily.If the lysine concentration drops, cell division slows; if the lysine concentration is restored, cell division resumes.Lysine is thus a(n)

A) fertilization signal.
B) ori site.
C) reproductive signal.
D) oncogene.
E) fission activator.

Answer 2

C

Question 3

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 G1 phase.
C) Inactive cells are arrested only in G2 phase.
D) During G2 the cell prepares for S phase.
E) None of the above; there is no difference in the nucleus between G1 and G2.

Answer 3

A

Question 4

Chromosomes contain large amounts of interacting proteins known as

A) pentanes.
B) centrosomes.
C) histones.
D) protein hormones.
E) cyclins.

Question 5

Regulation of the cell cycle is dependent on cyclins and cyclin-dependent kinases.The key that allows a cell to progress beyond the restriction point is

A) the presence of cyclin.
B) the absence of cyclin.
C) the presence of cyclin and Cdk.
D) phosphorylation of RB by Cdk.
E) the presence of external signals from growth factors.

Question 6

Cyclin-dependent kinases (Cdk's) catalyze the phosphorylation of targeted proteins, a process that

A) decreases the mass of 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.

Question 7

Which statement about cell division in prokaryotes and eukaryotes is true?

A) In prokaryotes, all cells divide if conditions are favorable; in eukaryotes, only a few cells divide, and they do so according to a developmental program.
B) In eukaryotes, all cells divide if conditions are favorable; in prokaryotes, only a few cells divide, and they do so according to a developmental program.
C) The process of segregation is more complicated in prokaryotes than in eukaryotes.
D) Reproductive signals for initiation of cell division are intracellular for prokaryotes and extracellular for eukaryotes.
E) The process of cytokinesis is more complicated in prokaryotes than in eukaryotes.

Question 8

An environmental change that leads to the production of less than the expected amount of cyclin would tend to _______ the activity of the Cdk.This would lead to _______ phosphorylation of the target protein, which in turn would lead to _______ cells being stopped at the checkpoint.

A) increase; increased; more
B) increase; decreased; fewer
C) increase: increased; fewer
D) decrease; increased; fewer
E) decrease; decreased; more

Question 9

If a cell in G2 has 1.6 pg of DNA, it had _______ of DNA in G1.

A) 0.4 pg
B) 0.8 pg
C) 1.6 pg
D) 3.2 pg
E) 1.6 pg if it is a plant cell and 3.2 pg if it is an animal cell

Question 10

Which event is not required for cell division?

A) Segregation of DNA
B) Cytokinesis
C) Crossing over
D) DNA replication
E) All of the above are required for cell division.

Question 11

Which situation would most likely result from a mutation in the ori gene of a bacterial cell?

A) The cell would not be able to detect whether conditions were favorable for replication.
B) The initiation of DNA replication would be hindered.
C) DNA replication would be prolonged abnormally.
D) The cell would not be able to segregate DNA molecules.
E) The cell could not undergo meiosis.

Question 12

Which statement 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.

Question 13

Which phase of the cell cycle is not part of interphase?

A) S
B) G0
C) G1
D) G2
E) M

Question 14

The DNA of a eukaryotic cell is

A) double-stranded and linear.
B) single-stranded and linear.
C) double-stranded and circular.
D) single-stranded and circular.
E) conservative.

Question 15

A set of cells in the intestinal epithelium divides continually in order to replace dead cells.A microscopic examination of this population of cells would show that most of them

A) have condensed chromatin.
B) are in meiosis.
C) are in mitosis.
D) are in interphase.
E) Both a and b

Question 16

During bacterial cell division, a single cell is separated into two cells by

A) centrosomes.
B) spindle fibers.
C) nucleosomes.
D) aneuploidy.
E) pinching of the plasma membrane.

Question 17

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.

Question 18

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.

Question 19

Which situation would be the most likely result of a mutation in a eukaryotic organism that causes it to produce less p21 protein than normal?

A) Cell replication would be slowed if the organism receives radiation.
B) Cells with radiation-induced DNA damage would continue through the cell cycle without repairing the damaged DNA.
C) Cells with incomplete DNA replication would continue through the checkpoint.
D) Cells would not respond to growth factors.
E) Cells would have a hypersensitive response to growth factors.

Question 20

Interleukins and erythropoietin are

A) intracellular signaling molecules.
B) Cdk's.
C) cyclins.
D) antitumor agents.
E) growth factors.

Question 21

Which situation 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.

Question 22

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.

Question 23

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.

Question 24

Late in mitotic anaphase, a cell with 28 daughter chromosomes has _______ centromeres in the dividing cell.

A) no
B) 14
C) 28
D) 56
E) None of the above

Question 25

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.

Question 26

Which event 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

Question 27

At the milestone that defines anaphase, the chromosomes

A) separate.
B) come together.
C) are at opposite poles.
D) line up.
E) cross over.

Question 28

In mitotic metaphase, a cell with eight sister chromatids has _______ centromere(s).

A) no
B) one
C) two
D) four
E) eight

Question 29

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.

Question 30

The energy to move chromosomes during mitosis is provided by

A) centrioles.
B) DNA polymerization.
C) ATP.
D) formation of the cell plate.
E) None of the above; energy is not required for this action.

Question 31

Refer to the figure showing a phase of mitosis. Which cell structures are indicated by the two leader lines?

A) Chromosomes
B) Centromeres
C) Chromatids
D) Kinetochore microtubules
E) Centrioles

Question 32

Centrosomes

A) are constricted regions of prophase 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.

Question 33

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.

Question 34

At the milestone that defines metaphase, the chromosomes

A) separate.
B) come together.
C) are at opposite poles.
D) cross over.
E) line up at the equatorial plate.

Question 35

During mitosis and meiosis the chromatin compacts.Which process takes place more easily because of this compaction?

A) The orderly distribution of genetic material to two new nuclei
B) DNA replication
C) The exposing of the genetic information on the DNA
D) The unwinding of DNA from the histones
E) The disappearance of the nuclear membrane

Question 36

Condensed chromatin consists of

A) DNA and histones.
B) DNA, histones, and many other proteins.
C) RNA and DNA.
D) RNA, DNA, and nonhistone proteins.
E) DNA only.

Question 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.

Question 38

Replacing arginine in a histone with a neutral amino acid would make the histone _______ positively charged and _______ likely to bind to DNA.

A) more; more
B) more; less
C) less; more
D) less; less
E) None of the above; this replacement would have no effect because arginine is a neutral amino acid.

Question 39

At the milestone that defines telophase, the chromosomes

A) separate.
B) come together.
C) cross over.
D) line up.
E) are at opposite poles.

Question 40

Chromatin condenses to form discrete, visible chromosomes

A) early in G1.
B) during S.
C) during metaphase.
D) during prophase.
E) at the end of cytokinesis.

Question 41

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.

Question 42

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.

Question 43

Refer to the figure showing a phase of mitosis. What phase is shown here?

A) Mitosis prophase
B) Mitosis metaphase
C) Mitosis anaphase
D) Meiosis prophase I
E) Meiosis prophase II

Question 44

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.

Question 45

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 as many chromosomes as a diploid cell.
E) None of the above

Question 46

Which statement about meiosis and mitosis is true?

A) DNA replication occurs only in mitosis and not in meiosis.
B) DNA replication occurs only in meiosis and not in mitosis.
C) The products of meiosis can be different from one another, while the products of mitosis are all the same (except for rare mutations).
D) The products of mitosis can be different from one another, while the products of meiosis are all the same (except for rare mutations).
E) Mitosis and meiosis are the same process.

Question 47

Which statement 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 are joined during prophase I and metaphase I at their common centromere.
E) They separate from each other during meiosis I.

Question 48

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.

Question 49

During meiosis, the sister chromatids separate during

A) anaphase I.
B) anaphase II.
C) S phase.
D) telophase I.
E) telophase II.

Question 50

In an organism with a haplontic life cycle, the adult multicellular organism is _______, and the time spent between fertilization and meiosis is _______ the time spent between meiosis and fertilization.

A) haploid; longer than
B) haploid; shorter than
C) diploid; longer than
D) diploid; equal to
E) diploid; shorter than

Question 51

In a particular diploid organism, somatic cells have 24 chromosomes.How many chromosomes would be present in the gametes of that organism?

A) 1
B) 6
C) 12
D) 24
E) 48

Question 52

Organisms that are haplontic differ from those that are diplontic in

A) whether their cell cycles contain checkpoints.
B) the number of chromosomes they contain.
C) the extent to which they develop in the diploid state during their life cycle.
D) whether they undergo meiosis.
E) None of the above

Question 53

The major drawback of asexual reproduction, as compared with sexual reproduction, is that it

A) takes a great deal of time.
B) generates variation.
C) requires cytokinesis.
D) produces less variation among offspring.
E) None of the above; there are no major drawbacks associated with asexual reproduction.

Question 54

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) crossing over.

Question 55

In the sexual life cycle called alternation of generations, an organism spends roughly equal amounts of time in the _______ and the _______ stages.

A) monosomic; trisomic
B) haploid; monosomic
C) haploid; diploid
D) prokaryotic; eukaryotic
E) haplontic; diplontic

Question 56

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.

Question 57

The distribution of mitochondria between the daughter cells during cytokinesis

A) is unequal.
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.

Question 58

A mechanism for increasing the genetic diversity of offspring is

A) mitosis.
B) cloning.
C) sexual reproduction.
D) cytokinesis.
E) fission.

Question 59

Most zygotes are

A) multicellular.
B) diploid.
C) animals.
D) clones.
E) gametes.

Question 60

Each diploid cell of a human female contains _______ of each type of chromosome.

A) 1
B) 2
C) 4
D) 23
E) 46

Question 61

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.

Question 62

Refer to the figure showing the artificial selection of wheat. If the haploid number is 7, how many chromosomes are in the gametes of the most modern form of wheat?

A) 7
B) 14
C) 21
D) 28
E) 35

Question 63

The second meiotic division of meiosis

A) returns the chromosome number to diploid before fertilization.
B) allows for crossing over and random distribution of chromosomes.
C) reduces cell size by dividing the cytoplasm in half.
D) prevents chromosome copies from doubling at each fertilization.
E) is a step required for fertilization to take place.

Question 64

A triploid nucleus will have difficulty undergoing 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.

Question 65

Refer to the figure showing crossing over. This figure depicts

A) prophase I.
B) prophase II.
C) metaphase I.
D) metaphase II.
E) anaphase.

Question 66

Refer to the figure showing the artificial selection of wheat. According to the figure, what is the ploidy level of the most modern form of wheat?

A) 1n
B) 2n
C) 3n
D) 4n
E) 6n

Question 67

A species of a grass has a haploid number of 14.How many different types of gametes can be produced from meiosis in a diploid individual from independent assortment alone (i.e., no crossing over)?

A) 2⁷
B) 2¹⁴
C) 2²⁸
D) 14²
E) 28²

Question 68

Which statement 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) All of the above are true; none is false.

Question 69

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

A) nondisjunctions.
B) inversions.
C) reciprocal translocations.
D) recombinations.
E) induced mutations.

Question 70

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.

Question 71

The diploid number for Norway rats is 42.How many different types of gametes can be produced from meiosis in a diploid organism from independent assortment alone (i.e., no crossing over)?

A) 2²¹
B) 2⁴²
C) 2⁸⁴
D) 21²
E) 42²

Question 72

Refer to the figure showing crossing over. Which statement about the chromosomes is true?

A) The red chromosomes are both derived from the same parent.
B) One of the red chromosomes and one of the blue chromosomes came from the same parent.
C) The two red chromosomes are homologous.
D) A centromere forms where the crossing over occurs.
E) Because these chromosomes are homologous, crossing over will not result in any genetic diversity.

Question 73

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.

Question 74

Mitotic prophase differs from prophase I of meiosis in that

A) chromatin becomes supercoiled only in mitotic prophase.
B) the nuclear envelope disappears only in prophase I of meiosis.
C) synapsis occurs only in mitotic prophase.
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.

Question 75

The diploid number of a species of conifer is 64.How many chromosomes would a monosomic individual have?

A) 31
B) 32
C) 63
D) 64
E) 65

Question 76

To produce larger seeds, researchers cross two varieties of a grain.These researchers are attempting to cause

A) aneuploidy.
B) autopolyploidy.
C) allopolyploidy.
D) apoptosis.
E) translocation.

Question 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.

Question 78

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.

Question 79

The diagnosis of Down syndrome is made by examining the individual's

A) spores.
B) karyotype.
C) chromatin.
D) nucleosomes.
E) kinetochores.

Question 80

The haploid number in Drosophila melanogaster is 4.How many chromosomes would a trisomic individual have?

A) 3
B) 7
C) 8
D) 9
E) 12