BIO101 EXAM 2 REVIEW 5

1) The centr omere is a region in which
A) chromatids remain attached to one another until anaphase . B) metaphase chromosomes become aligned at the metaphase plate. C) chromosomes are grouped during telophase.
D) the nucleus is located prior to mitosis. E) new spindle microtubules form at either end.

2) Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells?
A) 4 B) 8 C) 16 D) 32 E) 64

3) If there are 20 chromatids in a cell, how many centromeres are there?
A) 10 B) 20 C) 30 D) 40 E) 80

7) 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?
A) anaphase B) prophase C) telophase D) metaphase E) interphase

8) 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
A) the formation of the mitotic spindle.
B) anaphase . C) formation of the centrioles. D) chromatid assembly. E) the S phase of the cell cycle.

9) A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. How many picograms would be found at the end of S and the end of G 2 ?
A) 8; 8 B) 8; 16 C) 16; 8 D) 16 ; 16 E) 12; 16
Answer: D

10) During which phase of mitosis do the chromatids become chromosomes?
A) telophase B) anaphase C) prophase D) metaphase E) cytokinesis

10) What causes the decrease in the amount of cyclin at a specific point in the cell cycle?
A) an increase in production once the restriction point is passed B) the cascade of increased production once its protein is phosphorylated by Cdk C) the changing ratio of cytoplasm to genome D) its destruction by a process initiated by the activity of its complex with a cyclin
E) the binding of PDGF to receptors on the cell surface

11) Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active?
A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk

12) The cyclin component of MPF is destroyed toward the end of which phase?
A) G 0 B) G 1 C) S D) G 2 E) M

13) Which of the following describe(s) cyclin-dependent kinase ( Cdk )?
A) Cdk is inactive, or "turned off," in the presence of cyclin. B) Cdk is present throughout the cell cycle. C) Cdk is an enzyme that attaches phosphate groups to other proteins.
D) Cdk is inactive, or "turned off," in the presence of cyclin and it is present throughout the cell cycle. E) Cdk is present throughout the cell cycle and is an enzyme that attaches phosphate groups to other proteins.





14) If the cell whose nuclear material is shown in Figure 12.2 continues toward completion of mitosis, which of the following events would occur next?
A) cell membrane synthesis B) spindle fiber formation C) nuclear envelope breakdown
D) formation of telophase nuclei E) synthesis of chromatids

Use the data in Table 12.1 to answer the following questions.

The data were obtained from a study of the length of time spent in each phase of the cell cycle by cells of three eukaryotic organisms designated beta, delta, and gamma.



Table 12.1: Minutes Spent in Cell Cycle Phases

15) Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that
A) gamma contains more DNA than beta. B) beta and gamma contain the same amount of DNA.
C) beta cells reproduce asexually. D) gamma contains 48 times more DNA and RNA than beta.
E) beta is a plant cell and gamma is an animal cell.

16) The research team used the setup to study the incorporation of labeled nucleotides into a culture of lymphocytes