The Cell Cycle Review
What is the expected percent change in the DNA content of a typical eukaryotic cell as it progresses through the cell cycle from the start of the G1 phase to the end of the G2 phase?
+100%
Cancer can result from a variety of different mutational events. Which of the following is LEAST likely to result in the initiation of a cancerous tumor?
A defect in a cell-cycle checkpoint prevents a cell from entering the S phase
Glycogen synthetase kinase 3 beta is a protein kinase that has been implicated in many types of cancer. Depending on the cell type, the gene for glycogen synthetase kinase 3 beta (GSK3β) can act either as an oncogene or as a tumor suppressor. Which of the following best predicts how GSK3β mutations can lead to the development of cancer?
Cells with inactive GSK3β fail to trigger apoptosis
If chemical signals in the cytoplasm control the progression of a cell to the M phase of the cell cycle, then fusion of a cell in G1 with a cell in early M phase would most likely result in the
Condensation of chromatin in preparation of nuclear division in both cells
Which of the following best describes the role of mitosis in the cell cycle?
Distributing replicated chromosomes to daughter nuclei
DNA replication occurs
During the S phase of the cell cycle
Which of the following is true of mitosis?
It maintains the same chromosome number in the daughter cells as in the parent cell
A researcher examining a root tip observes a plant cell with condensed sister chromatids, kinetochores with attached microtubules, and individual chromosomes that are aligned at the equatorial plate of the cell. Which of the following best describes what the next process will be in the cell?
Paired chromatids will separate, and the new daughter chromosomes will move toward opposite poles of the cell
During mitosis, which of the following normally occurs?
Replicated chromosomes line up on the equatorial plate
Most cells that have become transformed into cancer cells have which of the following characteristics when compared to normal, healthy cells?
Shorter cell cycle
Which of the following best describes the effect of a drug that blocks the production of the mitotic cyclin?
The cell would be prevented from entering mitosis, and the cell would stop dividing
Cancer cells behave differently than normal body cells. For example, they ignore signals that tell them to stop dividing. Which of the following conditions will most likely cause a normal body cell to become a cancer cell?
The environment contains mutagens that induce mutations that affect cell-cycle regulator proteins.
Which of the following statements best describes how a growth factor stimulates cell division from outside a cell?
The growth factor binds to receptors on the cell surface, initiating a signal transduction pathway that activates specific target genes.
Researchers studying cell cycle regulation in budding yeast have observed that a mutation in the CDC15 gene causes cell cycle arrest in telophase when the yeast cells are incubated at an elevated temperature. Which of the following statements best predicts the effect of the cell cycle arrest on proliferating yeast cells?
The yeast cells will replicate their chromosomes but will fail to complete cytokinesis