cell cycle test

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%

The cell cycle of yeast cells grown in the nutrient-poor environment is approximately what percent of the cell cycle of yeast cells grown in the nutrient-rich environment?

168

If 2n = 48 for a particular cell, then the chromosome number in each cell after meiosis would be

24

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.

In most vertebrates, the sperm cell normally contributes which of the following to the new organism?

A haploid complement of chromosomes

Which of the following describes a mutation that would lead to an increase in the frequency of nondisjunction?

A mutation affecting checkpoint 3 proteins that prevents attachment of spindle fibers

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 (GSK 3B) can act either as an oncogene or as a tumor suppressor. Which of the following best predicts how GSK3B mutations can lead to the development of cancer?

Cells with inactive GSK 3B fail to trigger apoptosis.

Which of the following presents a correct interpretation of the changes in chromosome number depicted in Figure 1?

Chromosomes enter metaphase containing two chromatids attached by a centromere. During anaphase, the chromatids are separated, each becoming a chromosome. Cytokinesis distributes the chromosomes into two separate cells.

The diagram above illustrates which of the following processes?

Crossing-over

Which of the following best describes the role of mitosis in the cell cycle?

Distributing replicated chromosomes to daughter nuclei

Maturation promoting factor, MPF, is a cyclin-CDK complex that catalyzes the phosphorylation of other proteins to start mitosis. The activity level of MPF is dependent on the relative concentrations of the cyclin and CDK components of MPF (Figure 1). Based on Figure 1, which of the following describes the role of cyclin in the regulation of the cell cycle?

During M phase, the cyclin level peaks, resulting in an increased binding frequency with CDK.

The process depicted in the image above is best summarized by which of the following descriptions?

During meiosis, crossing over leads to recombination of alleles between homologous chromosomes.

Which of the following statements correctly describes the chromosomes in each daughter cell at the end of meiosis I?

Each daughter cell contains 12 chromosomes, each composed of two chromatids. Each chromosome is one of a pair of homologous chromosomes from the parent cell, with the other homologue found in the other daughter cel.

Which of the following research questions is best addressed by the experiment?

How do chemical messengers affect a cell's transition between the phases of the cell cycle?

Which of the following questions about genetic diversity could most appropriately be answered by analysis of the model in Figure 1 ?

How does the independent assortment of the two sets of homologous chromosomes increase genetic diversity?

The events listed below generally take place during meiosis. I. Synapsis occurs. II. Crossing-over is completed. III. Condensation of chromosomes begins. IV. Separation of homologous chromosomes begins. Which of the following is the correct sequence of these events?

II, I, II, IV

Researchers performed an experiment to determine the effect of certain genetic mutations on mitosis in tropical fruit fly embryos. They determined the percentage of cells in each of four phases of mitosis as shown in Figure 1. Which of the following patterns is shown by the data?

In mutant 3 cells, more time is spent in prophase/prometaphase than in the later stages of mitosis.

During prophase I replicated homologous chromosomes pair up and undergo synapsis. What testable question is generated regarding synapsis and genetic variability by Figure 1 ?

Is the distance between two gene loci related to crossover rate?

Scientists have found that DNA methylation suppresses crossing-over in the fungus Ascobolus immersus. Which of the following questions is most appropriately raised by this specific observation?

Is the level of genetic variation in the gametes related to the amount of DNA methylation observed?

Which of the following is true of mitosis?

It maintains the same chromosome number in the daughter cells as in the parent cell.

All of the following are true statements about meiosis in mammals EXCEPT:

It produces four genetically identical gametes.

Based on Figure 2, which of the following best supports the claim that drug X inhibits oxygen consumption?

Melanoma line 3 consumes statistically less oxygen per cell in the presence of drug X than it does in the presence of the solvent alone.

Both mitosis and meiosis begin with a parent cell that is diploid. Which of the following best describes mitosis and meiosis result in daughter cells with different numbers of chromosomes?

Mitosis produces two identical diploid daughter cells after one round of division. Meiosis produces four haploid daughter cells after two rounds of division.

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.

Which of the following occurs in both meiosis and mitosis?

Separation of sister chromatids

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 how the amount of DNA in the cell changes during M phase?

The amount of DNA is halved as the cell divides into two daughter cells.

Based on the model of eukaryotic cell cycle regulation shown in the figure, 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 v dividing.

Which of the following occurs during mitosis but not during meiosis I ?

The chromatids of each chromosome are separated.

Humans have a diploid number (2n) of 46. Which of the following statements best predicts the consequence if meiosis did not occur during gametogenesis?

The chromosome number would double with each generation.

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 best explains why triploid bananas do not produce seeds?

The production of gametes is disrupted because of unequal pairing of homologous chromosomes during meiosis.

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.

Which of the following best describes the cells that result from the process of meiosis in mammals?

They are genetically different from the parent cell.

Which of the following best explains the most likely method by which this antitumor drug works?

Trabectedin interferes with the duplication of DNA during interphase and thus prevents cancer cells from passing the G2 checkpoint.

a biochemist measured the amount of dna in cells growing in the laboratory and found that the quantity of dna in the cells doubled

between g1 and g2 phases of the cell cycle

DNA replication occurs

during the S phase of the cell cycle

dna replication occurs

during the S phase of the cell cycle

after normal meiotic division, how many chromosomes does each new daughter cell contain as compared to the parent cell

half as many

A human cell in prophase of mitosis can be distinguished from a human cell in prophase I of meiosis by the presence of

paired homologous chromosomes in the meiotic cell

if cells in the process of dividing are subjected to colchicine, a drug that interferes with the formation of the spindle apparatus, at which stage will mitosis be arrested

prophase

interphase includes all of the following activities except

spindle fibers attaching to centromeres on duplicated chromosomes

Based on Figure 1, what percent of the time required to complete a full cycle do the cells typically spend in interphase?

95%

the structures that hold chromatids together in a double stranded chromosomes are

centromeres

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