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Problem 1
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.
Problem 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.
Problem 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.
Problem 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.
Problem 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.
- Which of the following occurs during apoptosis? (A) lysis of the cell (B) direct contact between signaling cells (C) fragmentation of the DNA (D) release of proteases outside the cell
Problem 5
Problem 6
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
Problem 7
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.
Problem 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
Problem 9
VISUAL SKILLS The light micrograph shows dividing cells near the tip of an onion root. Identify a cell in each of the following stages: prophase, prometaphase, metaphase, anaphase, and telophase. Describe the major events occurring at each stage.
Problem 10
DRAW IT Draw one eukaryotic chromosome as it would appear during interphase, during each of the stages of mitosis, and during cytokinesis. Also draw and label the nuclear envelope and any microtubules attached to the chromosome(s).
