Cell Cycle End of the Chapter

Question 1

2. 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.

Answer 1

A) disruption of mitotic spindle formation.

Question 2

3. 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.

Answer 2

c. continue to divide even when they are tightly packed together

Question 3

4. 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

Answer 3

C) the degradation of cyclin.

Question 4

5. 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.

Answer 4

A) cells with more than one nucleus.

Question 5

6. Which of the following does not occur during mitosis? a. condensation of the chromosomes b. replication of the DNA c. separation of sister chromatids d. spindle formation

Answer 5

B) replication of the DNA

Question 6

7. A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in a. G1. b. G2.

Answer 6

A) G₁.

Question 7

8. 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 9. In the light micrograph below of dividing cells n

Answer 7

E) cleavage furrow formation and cytokinesis

Question 8

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.

Answer 8

B) a plant cell in the process of cytokinesis.