Chapter 12: The Cell Cycle – Flashcards

What is the correct order for the phases of the cell cycle?

Although the process of chromosome partitioning during mitosis is visible through a light microscope, the process of DNA replication is not. Why?

A certain species of animal has six pairs of chromosomes. How many sister chromatids do the nuclei of these animals have during G2 phase?

The length of the different phases of the cell cycle can be measured by performing a pulse-chase experiment with radioactive thymidine and waiting to see how long it takes for radioactivity to appear in mitotic chromosomes. After the radioactivity first arrives in mitotic chromosomes, it is observed that the amount of radioactivity in these chromosomes increases steadily over several hours, reaches a plateau, and then declines. What cell-cycle phase is measured by the time between the first and last appearance of radioactive thymidine in condensed, mitotic chromosomes?

The length of the different phases of the cell cycle can be measured by performing a pulse-chase experiment with radioactive thymidine and waiting to see how long it takes for radioactivity to appear in mitotic chromosomes. What cell-cycle phase is measured as the time between the end of radioactive thymidine labeling and the beginning of the appearance of radioactive mitotic chromosomes?

Mitotic spindle fibers are composed of what cellular components?

During mitosis, it is necessary for the nuclear envelope of the parent cell to disintegrate. This is accomplished in part by phosphorylation of proteins associated with the nuclear envelope. If the enzyme responsible for that phosphorylation event is inhibited, at which phase of mitosis are cells likely to arrest?

Taxol is a drug that stabilizes microtubules and prevents them from depolymerizing. Consequently, cells treated with taxol fail to complete mitosis. What is the last stage of mitosis that taxol-treated cells are likely to complete?

What would be the effect on the cell cycle of interphase frog oocytes if chromosomes from M phase oocytes were injected into them?

One interesting experiment conducted with frog oocytes revealed that with an appropriate stimulus, the cyclic appearance and disappearance of cyclin occurs even in the absence of a nucleus. What does this result imply about the production of cyclin in oocytes during the cell cycle?

Much of what is known about the function of cyclin and Cdk was learned by mutations in yeast. One yeast mutant is known as wee1. As its name implies, this yeast mutant never achieves full size. It divides continuously without allowing time for the cells to grow to their normal size. The defect is caused by inactivation of a gene that encodes a protein kinase. What might be a possible role for this kinase in normal wild-type yeast?

In an experiment to determine whether M-phase cells contain a regulatory molecule that initiates mitosis, cytoplasm from M-phase cells and interphase cells was injected separately into interphase cells. Why did researchers inject cytoplasm from interphase cells?

Which of the following conditions will most likely prevent a cell from passing the G1 checkpoint?

What mistake during anaphase can contribute to cancer formation?

Early detection is the key to successful treatment of most cancers. Why?

Many cancers are due to the failure of cells to properly regulate the _____ checkpoint during the cell cycle.

Exposure to chemicals that cause mutations in DNA greatly increases the chance of developing cancer. Mutations that inactivate which of the following proteins would most likely lead to cancer?

The consequence of E2F inactivation is that _____.

Progression though the cell cycle is regulated by oscillations in the concentration of which type of molecule?

After the S phase, what compromises a single chromosome?

What evidence suggest that during anaphase, kinetochore microtubules shorten at the kinetochore?

Under normal conditions, what happens to the cell cycle if the chromosomes fail to separate properly at anaphase?

Chromatin is ____

Which processes rely on a constricting ring of fibers?

Active MPK-CdK phosphorylates proteins that cause what?