Exam 9: The Cell Cycle

Cells from advanced malignant tumors often have very abnormal chromosomes as well as an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?

Use the following information to answer the questions below. Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. In a set of experiments, a student-faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times. -The research team used the setup to study the incorporation of labeled nucleotides into a culture of lymphocytes and found that the lymphocytes incorporated the labeled nucleotide at a significantly higher level after a pathogen was introduced into the culture. They concluded that

The following questions are based on Figure 9.3. Figure 9.3 -At which of the numbered regions would you expect to find cells at metaphase?

Use the following information to answer the questions below. Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. In a set of experiments, a student-faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times. -Which of the following does not occur during mitosis?

Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active?

The cyclin component of MPF is destroyed toward the end of which phase?

Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor tubulin. Surprisingly, this stops mitosis. Specifically, Taxol must affect

Which is the first checkpoint in the cell cycle where a cell will be caused to exit the cycle if this point is not passed?

Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells?

The following questions are based on Figure 9.3. Figure 9.3 -MPF reaches its threshold concentration at the end of this stage.

Where do the microtubules of the spindle originate during mitosis in animal cells?

Use the following information to answer the questions below. Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. In a set of experiments, a student-faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times. -Which of the following questions might be answered by such a method?

Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor?

The MPF protein complex turns itself off by

Use the following information to answer the questions below. The unlettered circle at the top of Figure 9.1 shows a diploid nucleus with four chromosomes that have not yet replicated. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is black, and the other is gray. The circles labeled A-E show various combinations of these chromosomes. Figure 9.1 -What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis?

The following information applies to the questions below. Several organisms, primarily protists, have what are called intermediate mitotic organization. -These protists are intermediate in what sense?

Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA?

Use the following information to answer the questions below. Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. In a set of experiments, a student-faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times. -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

Anchorage dependence of animal cells in vitro or in vivo depends on which of the following?

At which phase are centrioles beginning to move apart in animal cells?