Deck 12: Mitosis

Question 1

Which of the following statements describes a characteristic feature of metaphase?

A) alignment of chromosomes on the equator of the cell
B) separation of the centromeres
C) cytokinesis
D) separation of sister chromatids

Answer 1

A

Question 2

After DNA replication, each duplicated chromosome consists of two of which of the following structures?

A) daughter chromosomes
B) daughter nucleosomes
C) sister chromatids
D) sister chromatins

Answer 2

C

Question 3

At which phase of the cell cycle do centrioles begin to move apart in animal cells?

A) anaphase
B) telophase
C) metaphase
D) prophase

Answer 3

D

Question 4

Which of the following events would be most likely to produce cells with several nuclei?

A) repeated cytokinesis without mitosis
B) repeated mitosis with simultaneous cytokinesis
C) repeated mitosis without cytokinesis
D) multiple S phases without mitosis

Question 5

Students in a biology lab isolated cells in various phases of the cell cycle. A population of cells that have twice the DNA of G1 phase cells was most likely isolated from which of the following part of the cell cycle?

A) between the G1 and S phase
B) in the G2 phase
C) immediately after cytokinesis
D) at the beginning of the S phase

Question 6

What is the name of the region on duplicated chromosomes where the sister chromatids are most closely attached to each other?

A) the chromatin
B) the centromere
C) the cohesin
D) the centrosome

Question 7

Which of the following statements best describes how cytokinesis differs between plant and animal cells?

A) The contractile filaments found in plant cells are structures composed of carbohydrates; the cleavage furrow in animal cells is composed of contractile proteins.
B) Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
C) The structural proteins of plant cells separate the two cells; in animal cells, a cell membrane separates the two daughter cells.
D) Cytokinesis occurs between metaphase and anaphase in plant cells; it occurs after anaphase in animal cells.

Question 8

If there are 24 centromeres in a cell at anaphase of mitosis, how many chromosomes will be found in each daughter cell following cytokinesis?

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

Question 9

Eukaryotic chromatin is composed of which of the following macromolecules?

A) DNA and RNA
B) DNA only
C) DNA and proteins
D) DNA and phospholipids

Question 10

If a cell at metaphase of mitosis contains 32 sister chromatids, how many chromosomes will be present in a G1 cell?

A) 8
B) 16
C) 32
D) 64

Question 11

The mitotic spindle plays a critical role in which of the following processes?

A) splitting of the cell (cytokinesis) following mitosis
B) triggering condensation of chromosomes
C) dissolving the nuclear membrane
D) separation of sister chromatids

Question 12

Which of the following cellular events occur in the G1 phase of the cell division cycle?

A) normal growth and cell function
B) DNA replication
C) the beginning of mitosis
D) break down of the nuclear membrane

Question 13

The mass of DNA per nucleus in a certain fungus ranges from 4 to 10 picograms. Nuclei with 5 picograms of DNA are most likely derived from cells in which of the following parts of the cell cycle?

A) G1
B) late S
C) G2
D) early M

Question 14

FtsZ is a bacterial protein that forms a contractile ring involved in binary fission. Its function is analogous to which of the following structures in eukaryotic cells?

A) the cleavage furrow of eukaryotic animal cells
B) the cell plate of eukaryotic plant cells
C) the mitotic spindle of eukaryotic cells
D) the microtubule-organizing center of eukaryotic cells

Question 15

Beginning with a fertilized egg (zygote), how many cells will be present in the embryo following five rounds of cell division?

A) 10
B) 16
C) 32
D) 6

Question 16

Movement of the chromosomes during anaphase would be most directly affected by a drug that prevents which of the following events?

A) nuclear envelope breakdown
B) elongation of microtubules
C) shortening of microtubules
D) formation of a cleavage furrow

Question 17

What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle?

A) centriole
B) centrosome
C) centromere
D) kinetochore

Question 18

In a diploid cell with four chromosome pairs (2n = 8), how many centromeres will be found in a nucleus at G2 of the cell division cycle?

A) 4
B) 8
C) 16
D) 32

Question 19

In a diploid cell with four chromosome pairs (2n = 8), how many sister chromatids will be found in a nucleus at prophase of mitosis?

A) 4
B) 8
C) 16
D) 32

Question 20

Students in a biology lab isolated cells in various phases of the cell cycle. A population of cells that have 1 1/2 times the DNA of G1 phase cells was most likely isolated from which of the following parts of the cell cycle?

A) between the G1 and S phases
B) in the G2 phase
C) in the M phase
D) in the S phase

Question 21

Which of the following events occurs during interphase of the cell cycle?

A) condensation of the chromosomes
B) separation of the spindle poles
C) spindle formation
D) replication of the DNA

Question 22

The unlettered circle at the top of the accompanying figure shows a diploid nucleus with four unreplicated chromosomes. The circles labeled 1 to 5 show various combinations of these chromosomes. Which chromosomal configuration would be observed at prometaphase of mitosis?

A) II
B) III
C) IV
D) V

Question 23

In which phase of mitosis do the sister chromatids become daughter chromosomes?

A) telophase
B) anaphase
C) prophase
D) metaphase

Question 24

Amount of DNA per nucleus over the cell division cycle.
Which region of the accompanying figure represents S phase?

A) I
B) II
C) III
D) IV

Question 25

Use the figure to answer the question below. If the cell whose nuclear material is shown in the accompanying figure continues toward completion of mitosis, which of the following events would occur next?

A) spindle formation
B) nuclear envelope breakdown
C) formation of telophase nuclei
D) segregation of daughter chromosomes

Question 26

The drug cytochalasin B blocks the polymerization of actin microfilaments. Which of the following events of the cell cycle in animal cells would be most directly disrupted by cytochalasin B?

A) spindle formation
B) spindle attachment to kinetochores
C) movement of chromosomes to the poles during anaphase
D) cleavage furrow formation and cytokinesis

Question 27

Amount of DNA per nucleus over the cell division cycle.
G1 is represented by which numbered part(s) of the cell division cycle in the accompanying figure?

A) I and V
B) II
C) III
D) IV

Question 28

Which of the following statements best explains how neurons and some other specialized cells divide infrequently?

A) They no longer have active nuclei.
B) They have entered into G0.
C) They can no longer degrade cyclins.
D) They no longer produce MPF.

Question 29

Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely ________.

A) an animal cell in the process of cytokinesis
B) an animal cell in anaphase of mitosis
C) a plant cell in the process of cytokinesis
D) a plant cell in metaphase of mitosis

Question 30

Which of the following statements best describes a cleavage furrow?

A) a ring of vesicles forming a cell plate
B) the separation of divided prokaryotes
C) a groove in the plasma membrane between daughter nuclei
D) the space that is created between two chromatids during anaphase

Question 31

The unlettered circle at the top of the accompanying figure shows a diploid nucleus with four chromosomes that have not yet replicated. The circles labeled 1 to 5 show various combinations of these chromosomes. Which chromosomal configuration would be observed in one daughter cell after telophase of mitosis?

A) II
B) III
C) IV
D) V

Question 32

Which of the following pairs of molecules make up an active MPF?

A) a growth factor and mitotic factor
B) ATP synthetase and a protease
C) cyclin and tubulin
D) cyclin and a cyclin-dependent kinase

Question 33

Certain unicellular eukaryotes, including diatoms and some yeasts, have mechanisms of nuclear division that resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?

A) They reproduce by binary fission in their early stages of development and by mitosis when they are mature.
B) They have circular chromosomes that are segregated by a mitotic spindle.
C) Chromosomes are segregated by a mitotic spindle, but the nuclear envelope remains intact during division.
D) Chromosomes are segregated by attachment to the plasma membrane.

Question 34

A research team used a culture of lymphocytes with radioactively labeled T nucleotides to study the cell cycle. They found that the lymphocytes incorporated the labeled nucleotide at a significantly higher rate after a pathogen was introduced into the culture. Which of the following conclusions is most consistent with the results?

A) The pathogen consumed radiolabeled nucleotides.
B) Infection causes lymphocytes to divide more rapidly.
C) Infection causes lymphocytes to increase in size.
D) Infection causes lymphocyte cultures to skip some parts of the cell cycle.

Question 35

Amount of DNA per nucleus over the cell division cycle.
Which numbered regions of the accompanying figure represent the DNA content associated with cells at metaphase?

A) II and IV
B) II only
C) III only
D) IV only

Question 36

Which of the following structures or molecules is required in order for motor proteins to facilitate movement of chromosomes toward the poles in mitosis?

A) intact centromeres
B) actin microfilaments
C) ATP as an energy source
D) intact cohesin

Question 37

Which of the following events characterizes the beginning of anaphase?

A) loss of kinetochores from the chromatids
B) attachment of sister chromatids to each other by cohesin
C) enzymatic cleavage of cohesin
D) disappearance of the nuclear membrane

Question 38

One type of eukaryotic cell (line 1) spends 24 minutes in S phase and another type of cell (line 2) spends 48 minutes in S phase. Which of the following statements is the best explanation for the difference in time spent in S phase by cell lines 1 and 2? Amount of DNA per nucleus over the cell division cycle.

A) Line 2 contains more DNA than line 1.
B) Lines 1 and 2 contain the same amount of DNA.
C) Line 1 cells reproduce by binary fission and line 2 cells reproduce by mitosis and cytokinesis.
D) Line 2 has plant cells and line 1 has animal cells.

Question 39

Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol prevents microtubule depolymerization, which interferes with which of the following processes?

A) chromosome separation
B) cytokinesis
C) centriole duplication
D) chromosome condensation

Question 40

A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 10 picograms of DNA per nucleus. Approximately how many picograms of DNA would be found in a nucleus at prophase of mitosis?

A) 5
B) 10
C) 20
D) 40

Question 41

Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to ________.

A) disruption of mitotic spindle formation
B) suppression of cyclin production
C) myosin denaturation and inhibition of cleavage furrow formation
D) inhibition of DNA synthesis

Question 42

Exposure of zebrafish nuclei to cytosol isolated from eggs at metaphase of mitosis resulted in phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2. NEP55 is a protein of the inner nuclear membrane, and L68 is a protein of the nuclear lamina. What is the most likely role of phosphorylation of these proteins in the process of mitosis?

A) They enable the attachment of spindle microtubules to kinetochores.
B) They are involved in chromosome condensation.
C) They are involved in the disassembly of the nuclear envelope.
D) They are involved in migration of centrosomes to opposite sides of the nucleus.

Question 43

If all chromosomes are not attached to the mitotic spindle at the M phase checkpoint, the cells would most likely be arrested at which of the following points in the cell division cycle or mitosis?

A) telophase
B) prophase
C) G2
D) metaphase

Question 44

Which of the following molecules is synthesized at specific times during the cell cycle and forms an active complex with a kinase?

A) PDGF
B) MPF
C) cyclin
D) Cdk

Question 45

One difference between cancer cells and normal cells is that cancer cells ________.

A) are unable to synthesize DNA
B) are arrested at the S phase of the cell cycle
C) continue to divide even when they are tightly packed together
D) cannot function properly because they are affected by density-dependent inhibition

Question 46

Besides the ability of some cancer cells to over proliferate, which of the following situations is most likely to result in a tumor?

A) changes in the order of cell cycle stages
B) lack of appropriate cell death
C) inability to form spindles
D) failure of cells to enter S phase

Question 47

Progression beyond the G2 checkpoint into mitosis is triggered by which of the following molecules?

A) PDGF
B) MPF
C) cyclin
D) Cdk

Question 48

Which of the following statements best describes what happens to MPF during mitosis?

A) It is completely degraded.
B) It is phosphorylated by a Cdk, which inactivates it.
C) The cyclin component of MPF is degraded.
D) The Cdk component of MPF is degraded.

Question 49

Which of the following statements best describes cells in culture that do not exhibit either density-dependent inhibition or anchorage dependence?

A) The cells are unable to form spindle microtubules.
B) The cells follow an altered series of cell cycle phases.
C) The cells show characteristics of tumors.
D) The cells have nonfunctional MPF.

Question 50

Cells from advanced malignant tumors often have very abnormal chromosomes and an abnormal number of chromosomes. Which of the following best explains the association between malignant tumors and chromosomal abnormalities?

A) Cancer cells are no longer density-dependent.
B) Cancer cells are no longer anchorage-dependent.
C) Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.
D) Transformation introduces new chromosomes into cells.

Question 51

In the cells of some organisms, mitosis occurs without cytokinesis. This will result in ________.

A) cells with more than one nucleus
B) cells that are unusually small
C) cells lacking nuclei
D) cell cycles lacking an S phase

Question 52

The decline of MPF activity at the end of mitosis is due to ________.

A) the destruction of the protein kinase Cdk
B) decreased synthesis of Cdk
C) the degradation of cyclin
D) the accumulation of cyclin

Question 53

Amount of DNA per nucleus over the cell division cycle. At which point in the accompanying figure does MPF reach its highest activity during the cell division cycle?

A) I
B) II
C) III
D) IV

Question 54

Which of the following molecules is maintained at a relatively constant level throughout the cell cycle but requires a cyclin to become catalytically active?

A) PDGF
B) MPF
C) cyclin
D) Cdk

Question 55

Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely ________.

A) an animal cell in the process of cytokinesis
B) a plant cell in the process of cytokinesis
C) a bacterial cell dividing
D) a plant cell in metaphase

Question 56

Which of the following characteristics would be most important for a chemotherapeutic drug designed to treat cancer cells?

A) It is safe enough to prevent all apoptosis.
B) It does not interfere with metabolically active cells.
C) It specifically inhibits cells entering G0.
D) It specifically inhibits the cell division cycle in rapidly dividing cells.

Question 57

Which of the following statements best describes density-dependent inhibition?

A) As cells become more numerous, they begin to squeeze against each other, restricting their size.
B) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing.
C) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor.
D) As cells become more numerous, the level of waste products increases, which slows metabolism and inhibits growth.

Question 58

Which of the following statements best describes what would happen if MPF (maturation-promoting factor) is introduced into immature frog oocytes that are arrested in G2?

A) The cells would remain arrested in G2.
B) The cells would enter G0.
C) The cells would enter mitosis.
D) The cells would begin DNA synthesis.

Question 59

Which of the following properties is associated with a cyclin-dependent kinase (Cdk)?

A) A Cdk is inactive, or "turned off," in the presence of a cyclin.
B) The number of Cdk molecules increases during the S and G2 phases and decrease during M.
C) A Cdk is an enzyme that catalyzes the attachment of kinetochores to microtubules.
D) A Cdk is an enzyme that attaches phosphate groups to other proteins.

Question 60

At what stage of the cell cycle is the cyclin component of MPF destroyed?

A) in late G1
B) at mid-S phase
C) in early G2
D) in late M

Question 61

Which of the following occurs during S phase?

A) condensation of the chromosomes
B) replication of the DNA
C) separation of sister chromatids
D) spindle formation

Question 62

Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in ________.

A) G1
B) G2
C) prophase
D) metaphase

Question 63

The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B?

A) spindle formation
B) spindle attachment to kinetochores
C) cell elongation during anaphase
D) cleavage furrow formation and cytokinesis