Question 1

Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to

Accepted Answer

A) disruption of mitotic spindle formation. 
B) inhibition of regulatory protein phosphorylation. 
C) suppression of cyclin production. 
D) myosin denaturation and inhibition of cleavage furrow formation. 
E) inhibition of DNA synthesis. 
A) disruption of mitotic spindle formation. 
B) inhibition of regulatory protein phosphorylation. 
C) suppression of cyclin production. 
D) myosin denaturation and inhibition of cleavage furrow formation. 
E) inhibition of DNA synthesis. A

Question 2

The following questions are based on Figure 12.3.
  
-Which number represents the point in the cell cycle during which the chromosomes are replicated?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V B

Question 3

If mammalian cells receive a go-ahead signal at the G₁ checkpoint, they will

Accepted Answer

A) move directly into telophase. 
B) complete the cycle and divide. 
C) exit the cycle and switch to a nondividing state. 
D) show a drop in MPF concentration. 
E) complete cytokinesis and form new cell walls. 
A) move directly into telophase. 
B) complete the cycle and divide. 
C) exit the cycle and switch to a nondividing state. 
D) show a drop in MPF concentration. 
E) complete cytokinesis and form new cell walls. B

Question 4

Which of the following is True concerning cancer cells?

Accepted Answer

A) They do not exhibit density-dependent inhibition when growing in culture. 
B) When they stop dividing, they do so at random points in the cell cycle. 
C) They are not subject to cell cycle controls. 
D) B and C only 
E) A, B, and C 
A) They do not exhibit density-dependent inhibition when growing in culture. 
B) When they stop dividing, they do so at random points in the cell cycle. 
C) They are not subject to cell cycle controls. 
D) B and C only 
E) A, B, and C

Question 5

The centromere is a region in which

Accepted Answer

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. 
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.

Question 6

Fibroblasts have receptors for this substance on their plasma membranes:

Accepted Answer

A) PDGF 
B) MPF 
C) protein kinase 
D) cyclin 
E) Cdk 
A) PDGF 
B) MPF 
C) protein kinase 
D) cyclin 
E) Cdk

Question 7

DNA is replicated at this time of the cell cycle:

Accepted Answer

A) G₀ 
B) G₁ 
C) S 
D) G₂ 
E) M 
A) G₀ 
B) G₁ 
C) S 
D) G₂ 
E) M

Question 8

An enzyme that attaches a phosphate group to another molecule is called a

Accepted Answer

A) phosphatase. 
B) phosphorylase. 
C) kinase. 
D) cyclase. 
E) ATPase. 
A) phosphatase. 
B) phosphorylase. 
C) kinase. 
D) cyclase. 
E) ATPase.

Question 9

A mutation results in a cell that no longer produces a normal protein kinase for the M phase checkpoint. Which of the following would likely be the immediate result of this mutation?

Accepted Answer

A) The cell would prematurely enter anaphase. 
B) The cell would never leave metaphase. 
C) The cell would never enter metaphase. 
D) The cell would never enter prophase. 
E) The cell would undergo normal mitosis, but fail to enter the next G₁ phase. 
A) The cell would prematurely enter anaphase. 
B) The cell would never leave metaphase. 
C) The cell would never enter metaphase. 
D) The cell would never enter prophase. 
E) The cell would undergo normal mitosis, but fail to enter the next G₁ phase.

Question 10

Movement of the chromosomes during anaphase would be most affected by a drug that

Accepted Answer

A) reduces cyclin concentrations. 
B) increases cyclin concentrations. 
C) prevents elongation of microtubules. 
D) prevents shortening of microtubules. 
E) prevents attachment of the microtubules to the kinetochore. 
A) reduces cyclin concentrations. 
B) increases cyclin concentrations. 
C) prevents elongation of microtubules. 
D) prevents shortening of microtubules. 
E) prevents attachment of the microtubules to the kinetochore.

Question 11

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.
 $\begin{array} { l r r r r } 
\text { Cell Type } & \mathrm { G } _ { 1 } & \mathrm {~S} & \mathrm { G } _ { 2 } & M \
\hline \text { Beta } & 18 & 24 & 12 & 16 \
\text { Delta } & 100 & 0 & 0 & 0 \
\text { Gamma } & 18 & 48 & 14 & 20
\end{array}$ 
Table 12.1: Minutes Spent in Cell Cycle Phases
-Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that

Accepted Answer

A) gamma contains more DNA than beta. 
B) beta and gamma contain the same amount of DNA. 
C) beta contains more RNA than gamma. 
D) gamma contains 48 times more DNA and RNA than beta. 
E) beta is a plant cell and gamma is an animal cell. 
A) gamma contains more DNA than beta. 
B) beta and gamma contain the same amount of DNA. 
C) beta contains more RNA than gamma. 
D) gamma contains 48 times more DNA and RNA than beta. 
E) beta is a plant cell and gamma is an animal cell.

Question 12

In order for anaphase to begin, which of the following must occur?

Accepted Answer

A) Chromatids must lose their kinetochores. 
B) Cohesin must attach the sister chromatids to each other. 
C) Cohesin must be cleaved enzymatically. 
D) Kinetochores must attach to the metaphase plate. 
E) Spindle microtubules must begin to depolymerize. 
A) Chromatids must lose their kinetochores. 
B) Cohesin must attach the sister chromatids to each other. 
C) Cohesin must be cleaved enzymatically. 
D) Kinetochores must attach to the metaphase plate. 
E) Spindle microtubules must begin to depolymerize.

Question 13

The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B?

Accepted Answer

A) spindle formation 
B) spindle attachment to kinetochores 
C) DNA synthesis 
D) cell elongation during anaphase 
E) cleavage furrow formation 
A) spindle formation 
B) spindle attachment to kinetochores 
C) DNA synthesis 
D) cell elongation during anaphase 
E) cleavage furrow formation

Question 14

The decline of MPF activity at the end of mitosis is due to

Accepted Answer

A) the destruction of the protein kinase Cdk. 
B) decreased synthesis of cyclin. 
C) the degradation of cyclin. 
D) synthesis of DNA. 
E) an increase in the cell's volume-to-genome ratio. 
A) the destruction of the protein kinase Cdk. 
B) decreased synthesis of cyclin. 
C) the degradation of cyclin. 
D) synthesis of DNA. 
E) an increase in the cell's volume-to-genome ratio.

Question 15

Figure 12.2  
-If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis?

Accepted Answer

A) 10 
B) 20 
C) 30 
D) 40 
E) 80 
A) 10 
B) 20 
C) 30 
D) 40 
E) 80

Question 16

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

Accepted Answer

A) metastasis 
B) changes in the order of cell cycle stages 
C) lack of appropriate cell death 
D) inability to form spindles 
E) inability of chromosomes to meet at the metaphase plate 
A) metastasis 
B) changes in the order of cell cycle stages 
C) lack of appropriate cell death 
D) inability to form spindles 
E) inability of chromosomes to meet at the metaphase plate

Question 17

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

Accepted Answer

A) centromere 
B) centrosome 
C) centriole 
D) chromatid 
E) kinetochore 
A) centromere 
B) centrosome 
C) centriole 
D) chromatid 
E) kinetochore

Question 18

Use the following information to answer the questions below.
The lettered circle in Figure 12.1 shows a diploid nucleus with four chromosomes. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is symbolized as black and the other haploid set is gray. The chromosomes in the unlettered circle have not yet replicated. Choose the correct chromosomal conditions for the following stages.

-Which term describes centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell?

Accepted Answer

A) telophase 
B) anaphase 
C) prometaphase 
D) metaphase 
E) prophase 
A) telophase 
B) anaphase 
C) prometaphase 
D) metaphase 
E) prophase

Question 19

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

Accepted Answer

A) PDGF 
B) MPF 
C) protein kinase 
D) cyclin 
E) Cdk 
A) PDGF 
B) MPF 
C) protein kinase 
D) cyclin 
E) Cdk

Question 20

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. Those cells would have __________ picograms at the end of the S phase and __________ picograms at the end of G₂.

Accepted Answer

A) 8; 8 
B) 8; 16 
C) 16; 8 
D) 16; 16 
E) 12; 16 
A) 8; 8 
B) 8; 16 
C) 16; 8 
D) 16; 16 
E) 12; 16

Exam 12: The Cell Cycle

Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to

The following questions are based on Figure 12.3. -Which number represents the point in the cell cycle during which the chromosomes are replicated?

If mammalian cells receive a go-ahead signal at the G₁ checkpoint, they will

Which of the following is True concerning cancer cells?

The centromere is a region in which

Fibroblasts have receptors for this substance on their plasma membranes:

DNA is replicated at this time of the cell cycle:

An enzyme that attaches a phosphate group to another molecule is called a

A mutation results in a cell that no longer produces a normal protein kinase for the M phase checkpoint. Which of the following would likely be the immediate result of this mutation?

Movement of the chromosomes during anaphase would be most affected by a drug that

In order for anaphase to begin, which of the following must occur?

The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B?

The decline of MPF activity at the end of mitosis is due to

Figure 12.2 -If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis?

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

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

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

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. Those cells would have __________ picograms at the end of the S phase and __________ picograms at the end of G₂.

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and the Fitness of the Environment

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration: Harvesting Chemical Energy

Photosynthesis

Cell Communication

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Control of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure, Growth, and Development

Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems

Conservation Biology and Restoration Ecology

Filters

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. Those cells would have picograms at the end of the S phase and picograms at the end of G₂.