Question 1

At the start of mitosis, how many centromeres are present in a human cell?

Accepted Answer

A)  12
B)  23
C)  46
D)  92E) C) and D)
F) None of the above

Question 2

When nutrients are suboptimal for cell growth and division, the cell cycle arrests. At which stage of the cell cycle/checkpoint would you predict this arrest to occur?

Accepted Answer

A)  G1 checkpoint
B)  G2 checkpoint
C)  M checkpoint
D)  G1, G2, and the M checkpoints
E)  It is not possible to answer with the information given.F) All of the above
G) B) and C)

Question 3

Taxol is an anti-cancer drug that prevents uncontrolled cell proliferation by stabilizing microtubules, which causes arrest of the cell cycle. If dividing cells are treated with Taxol, at what stage of the cell cycle would you predict the arrest would occur?

Accepted Answer

A)  prophase
B)  metaphase
C)  anaphase
D)  telophase
E)  G1 of interphaseF) B) and D)
G) A) and C)

Question 4

It is estimated that there are a total of 50-100 trillion cells in the human body. Starting from a fertilized egg, how many cell divisions would be required to produce 50 trillion cells, assuming that every cell divides in every cycle?

Accepted Answer

A)  455 divisions
B)  45.5 divisions
C)  100 divisions
D)  one division per day for nine monthsE) None of the above
F) A) and B)

Question 5

Look carefully at the image of the human karyotype shown in Figure 11.3. What is the significance of the small differences between homologous chromosomes?  Photo credit: ISM/Phototake.

Accepted Answer

A)  Each homologous chromosome in a pair is from a different parent.
B)  Some of this person's DNA is mutated, possibly causing disease.
C)  Chromosomes may not be completely replicated during S phase.
D)  The differences are a result of the way the material was prepared.E) None of the above
F) A) and D)

Question 6

CDKs are important in the regulation of the cell cycle. They carry out their function by:

Accepted Answer

A)  adding phosphate groups to target proteins.
B)  removing phosphate groups from target proteins.
C)  degrading cyclin proteins.
D)  preventing the progression of a cell from one stage of the cell cycle to the next.E) A) and B)
F) A) and C)

Question 7

Mitosis MOST likely evolved from what process?

Accepted Answer

A)  meiosis
B)  the cell cycle
C)  cytokinesis
D)  binary fissionE) A) and C)
F) None of the above D

Question 8

In which phase of mitosis do spindle microtubules shorten?

Accepted Answer

A)  prophase
B)  metaphase
C)  anaphase
D)  telophaseE) A) and C)
F) B) and D)

Question 9

What type of gene is c-src (cellular-src) ?

Accepted Answer

A)  oncogene
B)  tumor suppressor
C)  proto-oncogene
D)  growth factorE) None of the above
F) A) and D)

Question 10

A human cell with a total of 23 chromosomes is:

Accepted Answer

A)  haploid.
B)  diploid.
C)  polyploid.
D)  aneuploid.E) C) and D)
F) A) and B)

Question 11

Tumor suppressors oppose oncogenes by:

Accepted Answer

A)  slowing cell division.
B)  repairing mutations.
C)  instructing defective cells to die.
D)  blocking the action of an oncogene.
E)  All of these choices are correct.F) A) and B)
G) C) and D)

Question 12

What is a cyclin?

Accepted Answer

A)  a protein that activates kinases
B)  a protein whose levels change with the cell cycle
C)  a kinase
D)  a protein that activates kinases and a protein whose levels change with the cell cycleE) A) and C)
F) None of the above

Question 13

Which of the following statements is NOT true about gamete formation in mammals?

Accepted Answer

A)  In the female, the separation of cytoplasm is unequal during meiosis.
B)  Only one of the four cells resulting from meiosis goes on to become an oocyte.
C)  Only one of the four cells resulting from meiosis goes on to become an egg, which becomes a zygote upon fertilization by a sperm cell.
D)  The polar bodies formed during meiosis in the female can participate in fertilization with sperm.
E)  The cytoplasm is diminished during development of sperm, and a flagellum is formed to give sperm locomotion.F) None of the above
G) A) and B)

Question 14

Homologous pairs of chromosomes separate during:

Accepted Answer

A)  mitosis.
B)  meiosis I and mitosis.
C)  meiosis II and mitosis.
D)  meiosis I.
E)  meiosis II.F) A) and E)
G) All of the above

Question 15

In which phase of mitosis do chromosomes line up at the middle of the cell?

Accepted Answer

A)  prophase
B)  metaphase
C)  anaphase
D)  telophaseE) C) and D)
F) None of the above

Question 16

What happens to CDKs in the absence of cyclins?

Accepted Answer

A)  They are inactive.
B)  They are degraded.
C)  They become phosphorylated.
D)  They are inactive and become phosphorylated.E) A) and C)
F) C) and D)

Question 17

What would happen during cell division if the cell is deficient in actin?

Accepted Answer

A)  The sister chromatids would not separate.
B)  The mitotic spindle would not form.
C)  The cell would not divide.
D)  The centromeres would not split.E) A) and B)
F) A) and C)

Question 18

A graduate student is planning an experiment to evaluate the expression of PDGF-related genes in her cell population of interest. As a control, she hopes to confirm the expression of genes that are present in all dividing cells. For her controls, she should evaluate the expression of:

Accepted Answer

A)  PDGF.
B)  laminin.
C)  G proteins.
D)  CDKs.
E)  Notch.F) A) and B)
G) None of the above D

Question 19

A woman has her genome sequenced and finds that she carries a mutation in p53. Will she develop cancer?

Accepted Answer

A)  No, mutations in p53 do not contribute to cancer.
B)  Yes, she will certainly develop cancer given the role of p53 in the cell cycle.
C)  Possiblythis mutation may predispose her to developing certain types of cancer.D) A) and C)
E) None of the above C

Question 20

Why does meiosis result in more genetic variation than can be explained by mutation alone?

Accepted Answer

A)  because of the events of meiosis I
B)  because of the events of meiosis II
C)  because of crossing over
D)  not all the DNA gets replicatedE) A) and D)
F) B) and C)

Exam 11: Cell Division: Variations, Regulation, and Cancer

At the start of mitosis, how many centromeres are present in a human cell?

Correct AnswerverifiedShow Answer

When nutrients are suboptimal for cell growth and division, the cell cycle arrests. At which stage of the cell cycle/checkpoint would you predict this arrest to occur?

Correct AnswerverifiedShow Answer

Taxol is an anti-cancer drug that prevents uncontrolled cell proliferation by stabilizing microtubules, which causes arrest of the cell cycle. If dividing cells are treated with Taxol, at what stage of the cell cycle would you predict the arrest would occur?

Correct AnswerverifiedShow Answer

It is estimated that there are a total of 50-100 trillion cells in the human body. Starting from a fertilized egg, how many cell divisions would be required to produce 50 trillion cells, assuming that every cell divides in every cycle?

Correct AnswerverifiedShow Answer

Look carefully at the image of the human karyotype shown in Figure 11.3. What is the significance of the small differences between homologous chromosomes? Photo credit: ISM/Phototake.

Correct AnswerverifiedShow Answer

CDKs are important in the regulation of the cell cycle. They carry out their function by:

Correct AnswerverifiedShow Answer

Mitosis MOST likely evolved from what process?

Correct AnswerverifiedD

In which phase of mitosis do spindle microtubules shorten?

Correct AnswerverifiedShow Answer

What type of gene is c-src (cellular-src) ?

Correct AnswerverifiedShow Answer

A human cell with a total of 23 chromosomes is:

Correct AnswerverifiedShow Answer

Tumor suppressors oppose oncogenes by:

Correct AnswerverifiedShow Answer

What is a cyclin?

Correct AnswerverifiedShow Answer

Which of the following statements is NOT true about gamete formation in mammals?

Correct AnswerverifiedShow Answer

Homologous pairs of chromosomes separate during:

Correct AnswerverifiedShow Answer

In which phase of mitosis do chromosomes line up at the middle of the cell?

Correct AnswerverifiedShow Answer

What happens to CDKs in the absence of cyclins?

Correct AnswerverifiedShow Answer

What would happen during cell division if the cell is deficient in actin?

Correct AnswerverifiedShow Answer

A graduate student is planning an experiment to evaluate the expression of PDGF-related genes in her cell population of interest. As a control, she hopes to confirm the expression of genes that are present in all dividing cells. For her controls, she should evaluate the expression of:

Correct AnswerverifiedD

A woman has her genome sequenced and finds that she carries a mutation in p53. Will she develop cancer?

Correct AnswerverifiedC

Why does meiosis result in more genetic variation than can be explained by mutation alone?

Correct AnswerverifiedShow Answer

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D

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