EXAM 4 Chapter 12

From the image below, how many chromosomes are in the middle cell? A. 1 B. 2 C. 4 D. 8

1

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

16

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

24

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

4

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 G2phases 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.

A Cdk is an enzyme that attaches phosphate groups to other proteins.

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

ATP as an energy source

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.

As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing.

Which statement about typical eukaryotic chromosomes just before and after M phase is incorrect? A. These chromosomes are not in a fully condensed state. B. Both contain double-stranded DNA molecules. C. Both have just one kinetochore structure associated with their centromere. D. Both have many proteins associated with the chromosomal DNA. E. Typically, both are linear structures with distinct ends.

Both have just one kinetochore structure associated with their centromere.

Which statement comparing cancer cells and normal somatic cells would lose points on a test? A. Cancer cells often deactivate their apoptosis systems. B. Cancer cells are not as sensitive to contact inhibition. C. The cell cycle often proceeds faster in cancer cells. D. Cancer cells are more mobile and less dependent on anchorage. E. Cancer cells have more effective DNA repair activities.

Cancer cells have more effective DNA repair activities.

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

Cdk

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.

Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.

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

DNA and proteins

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

G1

Which comes immediately after S phase in the cell cycle? A. G1 B. G2 C. mitosis D. cytokinesis

G2

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

II

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.

It specifically inhibits the cell division cycle in rapidly dividing cell

If you were given a slide and told that the cells on it were performing cytokinesis, how would you tell if you had plant cells or animal cells? A. Look for a cell plate or a cleavage furrow. B. Look for condensed or decondensed chromosomes. C. Look for an intact or a dispersed nuclear membrane. D. Look for more or less layers in the cell wall.

Look for a cell plate or a cleavage furrow.

At what part of the cell cycle would you see a chromosome that looks like this? A. G1 B. G2 C. M D. S

M

If you used a very fine glass needle to pull one chromosome away from the metaphase plate during metaphase, which checkpoint would not be passed until this was corrected? A. G1 checkpoint B. G2 checkpoint C. M checkpoint D. S checkpoint E. any checkpoint

M checkpoint

Progression beyond the G2 checkpoint into mitosis is triggered by which of the following molecules? A. PDGF B. MPF C. cyclin D. Cdk

MPF

A new cell is found and separation of its chromosomes is examined. If the darker patches in the yellow lines are places where the spindle was bleached with a laser, what do these images tell us? A. Chromosomes are separated by microfilaments. B. Chromosomes are not separated. C. Microtubules shorten at the centrosome end. D. Microtubules shorten at the chromosome end.

Microtubules shorten at the centrosome end

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

N/A

Which of the following statements best describe show 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.

Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.

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.

The cells show characteristics of tumors.

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.

The cells would enter mitosis.

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.

The cyclin component of MPF is degraded.

Which event will likely occur next in a eukaryotic cell entering prometaphase? A. The chromosome material will condense. B. Chromosomes will be moved toward alignment at the metaphase plate. C. Kinetochores will link some microtubules to the centromeres. D. The nuclear membranes will fragment into vesicles. E. Microtubules will elongate into the nuclear space.

The nuclear membranes will fragment into vesicles.

Of the events of a typical cell division listed below, which is most likely to occur third in an animal cell that is going through mitosis? A. Kinetochore proteins associated with the centromeres bind with associated microtubules. B. Segregation of complete genomic sets of chromosomes occurs. C. The nuclear envelope membranes are converted from flat bilayers into many spherical vesicles. D. The number of chromosomes in the cell doubles as double-chromatid chromosomes are split into pairs of single-chromatid chromosomes. E. Vesicles fuse to one another to form new nuclear envelope membranes.

The number of chromosomes in the cell doubles as double-chromatid chromosomes are split into pairs of single-chromatid chromosomes.

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.

They have entered into G0.

From question 36, which chromosomal configuration would be observed in one daughter cell after telophase of mitosis? A. II B. III C. IV D. V

V

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

a groove in the plasma membrane between daughter nuclei

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

a plant cell in the process of cytokinesis

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

a plant cell in the process of cytokinesis

Which best describes the kinetochore? A. a structure composed of several proteins that associate with the centromere region of a chromosome and that can bind to spindle microtubules B. the centromere region of a metaphase chromosome where the DNA can bind with spindle proteins C. the array of vesicles that will form between two dividing nuclei and give rise to the metaphase plate D. the ring of actin microfilaments that will cause the appearance of the cleavage furrow E. the core of proteins that forms the cell plate in a dividing plant cell

a structure composed of several proteins that associate with the centromere region of a chromosome and that can bind to spindle microtubules

The chromosome begins M phase looking as shown. When does it split? A. prophase B. prometaphase C. metaphase D. anaphase E. telophase

anaphase

Binary fission is more like animal cell division than plant cell division because A. bacteria and animals have more organelles than plants. B. bacteria and animals both pinch in to separate the into two pieces. C. bacteria and animals use microfilaments to divide the cell. D. bacteria and animals both have two copies of each chromosome, while plants have four.

bacteria and animals both pinch in to separate the into two pieces.

If a cell that had two copies of each chromosome, but problems with the spindle caused the sister chromatids to remain attached to each other and to only one spindle pole, what cells would result? A. cells with 2 copies of each chromosome and 2 copies of each chromosome B. cells with 3 copies of each chromosome and 1 copy of each chromosome C. cells with 6 copies of each chromosome and 2 copies of each chromosome D. cells with 4 copies of each chromosome and 0 copies of each chromosome ​E. cells with 1 copy of each chromosome and 1 copy of each chromosome

cells with 4 copies of each chromosome and 0 copies of each chromosome

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

cells with more than one nucleus

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

centrosome

From the pole to the chromosome, what is the correct order? A. centrosome, microtubule, kinetochore, chromosome B. microtubule, kinetochore, chromosome, centrosome C. centrosome, kinetochore, microtubule, chromosome D. centrosome, kinetochore, chromosome, microtubule

centrosome, microtubule, kinetochore, chromosome

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

cleavage furrow formation and cytokinesis

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

continue to divide even wen they are tightly packed together

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

cyclin

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

cyclin and a cyclin-dependent kinase

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

cytokinesis

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

disruption of mitotic spindle formation

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 cohesion C. enzymatic cleavage of cohesion D. disappearance of the nuclear membrane

enzymatic cleavage of cohesion

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

in late M

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

in the G2 phase

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

lack of appropriate cell death

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

metaphase

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

normal growth and cell function

You are observing a line of rat cells and see that they repeatedly make mistakes in the cell cycle by going through the G2 checkpoint too early. This could be due to a A. problem with expression of a cyclin. B. misplaced MPF. C. defective chromosome. D. misfolded centromere protein.

problem with expression of a cyclin.

At which phase of the cell cycle do centrioles begin to move apart in animal cells? A. anaphase B. telophase C. metaphase D. prophase

prophase

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

replication of the DNA

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

replication of the DNA

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

segregation of daughter chromosomes

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

separation of sister chromatids

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

shortening of microtubules

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

sister chromatids

In which phase of mitosis do the sister chromatids become daughter chromosomes? A. telophase B. anaphase C. prophase D. metaphase

telophase

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 cohesion D. the centrosome

the centromere

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

the cleavage furrow of eukaryotic animal cells

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

the degradation of cyclin

From prophase through metaphase of mitosis, each chromosome has _____ DNA molecules, while from anaphase through telophase of mitosis, each chromosome has _____ DNA molecule(s). A. two; one B. 2n; 1n C. homologous; nonhomologous D. condensed; decondensed E. nonsister chromatid; sister chromatid

two; one