Question 1

BRCA1 and BRCA2 are considered to be tumor suppressor genes because ________.

Accepted Answer

A)  they prevent infection by tumor viruses that cause cancer 
B)  their normal products participate in repair of DNA damage 
C)  the mutant forms of either one of these prevent breast cancer 
D)  the normal genes make estrogen receptors 
E)  they block penetration of breast cells by chemical carcinogens 
A)  they prevent infection by tumor viruses that cause cancer 
B)  their normal products participate in repair of DNA damage 
C)  the mutant forms of either one of these prevent breast cancer 
D)  the normal genes make estrogen receptors 
E)  they block penetration of breast cells by chemical carcinogens B

Question 2

The MPF protein complex turns itself off by ________.

Accepted Answer

A)  activating a process that destroys cyclin components 
B)  activating an enzyme that stimulates cyclin 
C)  binding to chromatin 
D)  exiting the cell 
E)  activating the anaphase-promoting complex 
A)  activating a process that destroys cyclin components 
B)  activating an enzyme that stimulates cyclin 
C)  binding to chromatin 
D)  exiting the cell 
E)  activating the anaphase-promoting complex A

Question 3

How is plant cell cytokinesis different from animal cell cytokinesis?

Accepted Answer

A)  The contractile filaments found in plant cells are structures composed of carbohydrates; the cleavage furrow in animal cells is composed of contractile phospholipids. 
B)  Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow. 
C)  The structural proteins of plant cells separate the two cells; in animal cells, a cell membrane separates the two daughter cells. 
D)  Plant cells divide after metaphase but before anaphase; animal cells divide after anaphase. 
A)  The contractile filaments found in plant cells are structures composed of carbohydrates; the cleavage furrow in animal cells is composed of contractile phospholipids. 
B)  Plant cells deposit vesicles containing cell-wall building blocks on the metaphase plate; animal cells form a cleavage furrow. 
C)  The structural proteins of plant cells separate the two cells; in animal cells, a cell membrane separates the two daughter cells. 
D)  Plant cells divide after metaphase but before anaphase; animal cells divide after anaphase. B

Question 4

The following question(s) are based on the accompanying figure.  
-In the figure, mitosis is represented by which numbered part(s) of the cycle?

Accepted Answer

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

Question 5

Neurons and some other specialized cells divide infrequently because they ________.

Accepted Answer

A)  no longer have active nuclei 
B)  no longer carry receptors for signal molecules 
C)  have entered into G0 
D)  can no longer bind Cdk to cyclin 
E)  show a drop in MPF concentration 
A)  no longer have active nuclei 
B)  no longer carry receptors for signal molecules 
C)  have entered into G0 
D)  can no longer bind Cdk to cyclin 
E)  show a drop in MPF concentration

Question 6

FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis. Its function is analogous to ________.

Accepted Answer

A)  the cleavage furrow of eukaryotic animal cells 
B)  the cell plate of eukaryotic plant cells 
C)  the mitotic spindle of eukaryotic cells 
D)  the microtubule-organizing center of eukaryotic cells 
A)  the cleavage furrow of eukaryotic animal cells 
B)  the cell plate of eukaryotic plant cells 
C)  the mitotic spindle of eukaryotic cells 
D)  the microtubule-organizing center of eukaryotic cells

Question 7

Cyclin-dependent kinase (Cdk) is ________.

Accepted Answer

A)  inactive, or "turned off," in the presence of cyclin 
B)  present only during the S phase of the cell cycle 
C)  an enzyme that removes hydroxyl groups from growth hormones 
D)  the enzyme that catalyzes the attachment of chromosomes to microtubules 
E)  an enzyme that attaches phosphate groups to other proteins 
A)  inactive, or "turned off," in the presence of cyclin 
B)  present only during the S phase of the cell cycle 
C)  an enzyme that removes hydroxyl groups from growth hormones 
D)  the enzyme that catalyzes the attachment of chromosomes to microtubules 
E)  an enzyme that attaches phosphate groups to other proteins

Question 8

Tumor suppressor genes ________.

Accepted Answer

A)  are frequently overexpressed in cancerous cells 
B)  are cancer-causing genes introduced into cells by viruses 
C)  encode proteins that help prevent uncontrolled cell growth 
D)  often encode proteins that stimulate the cell cycle 
A)  are frequently overexpressed in cancerous cells 
B)  are cancer-causing genes introduced into cells by viruses 
C)  encode proteins that help prevent uncontrolled cell growth 
D)  often encode proteins that stimulate the cell cycle

Question 9

Mitosis separates chromosomes. Cytoplasm is divided between two daughter cells by ________.

Accepted Answer

A)  cloning 
B)  cytokinesis 
C)  binary fission 
D)  the formation of kinetochores 
A)  cloning 
B)  cytokinesis 
C)  binary fission 
D)  the formation of kinetochores

Question 10

The mitotic spindle is a microtubular structure that is involved in ________.

Accepted Answer

A)  splitting of the cell (cytokinesis) following mitosis 
B)  triggering the compaction and condensation of chromosomes 
C)  dissolving the nuclear membrane 
D)  separation of sister chromatids 
A)  splitting of the cell (cytokinesis) following mitosis 
B)  triggering the compaction and condensation of chromosomes 
C)  dissolving the nuclear membrane 
D)  separation of sister chromatids

Question 11

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 Cdk 
C)  the degradation of cyclin 
D)  the accumulation of cyclin 
E)  synthesis of DNA 
A)  the destruction of the protein kinase Cdk 
B)  decreased synthesis of Cdk 
C)  the degradation of cyclin 
D)  the accumulation of cyclin 
E)  synthesis of DNA

Question 12

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 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

Question 13

Use the following information to answer the question(s) below.
The unlettered circle at the top of the accompanying figure 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 to E show various combinations of these chromosomes.  
-What is the correct chromosomal condition at prometaphase of mitosis?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 14

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

Question 15

Use the following information to answer the question(s) below.
The unlettered circle at the top of the accompanying figure 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 to E show various combinations of these chromosomes.  
-What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
E)  E 
A)  A 
B)  B 
C)  C 
D)  D 
E)  E

Question 16

The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does NOT happen, cells would most likely be arrested in ________.

Accepted Answer

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

Question 17

During which phase of mitosis do the chromatids become chromosomes?

Accepted Answer

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

Question 18

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?

Accepted Answer

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

Question 19

Forms of the Ras protein found in tumors usually cause which of the following?

Accepted Answer

A)  DNA replication to stop 
B)  DNA replication to be hyperactive 
C)  cell-to-cell adhesion to be nonfunctional 
D)  cell division to cease 
E)  excessive cell division 
A)  DNA replication to stop 
B)  DNA replication to be hyperactive 
C)  cell-to-cell adhesion to be nonfunctional 
D)  cell division to cease 
E)  excessive cell division

Question 20

The first gap in the cell cycle (G1) corresponds to ________.

Accepted Answer

A)  normal growth and cell function 
B)  the phase in which DNA is being replicated 
C)  the beginning of mitosis 
D)  the phase between DNA replication and the M phase 
A)  normal growth and cell function 
B)  the phase in which DNA is being replicated 
C)  the beginning of mitosis 
D)  the phase between DNA replication and the M phase

Exam 12: The Cell Cycle

BRCA1 and BRCA2 are considered to be tumor suppressor genes because ________.

The MPF protein complex turns itself off by ________.

How is plant cell cytokinesis different from animal cell cytokinesis?

The following question(s) are based on the accompanying figure. -In the figure, mitosis is represented by which numbered part(s) of the cycle?

Neurons and some other specialized cells divide infrequently because they ________.

FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis. Its function is analogous to ________.

Cyclin-dependent kinase (Cdk) is ________.

Tumor suppressor genes ________.

Mitosis separates chromosomes. Cytoplasm is divided between two daughter cells by ________.

The mitotic spindle is a microtubular structure that is involved in ________.

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

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 G2?

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 M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does NOT happen, cells would most likely be arrested in ________.

During which phase of mitosis do the chromatids become chromosomes?

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?

Forms of the Ras protein found in tumors usually cause which of the following?

The first gap in the cell cycle (G1) corresponds to ________.

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Ecosystems and Global Ecology

Lipids, Membranes, and the First Cells

Inside the Cell

Energy and Enzymes: an Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cellcell Interactions

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, Rna Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

The Molecular Revolution: Biotechnology and Beyond

Genes, Development, and Evolution

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

Bacteria and Archaea

Protists

Green Algae and Land Plants

Fungi

An Introduction to Animals

Protostome Animals

Deuterostome Animals

Viruses

Plant Form and Function

Water and Sugar Transport in Plants

Plant Nutrition

Plant Sensory Systems, Signals, and Responses

Plant Reproduction and Development

Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Animal Nervous Systems

Animal Sensory Systems

Animal Movement

Chemical Signals in Animals

Animal Reproduction and Development

The Immune System in Animals

An Introduction to Ecology

Behavioral Ecology

Population Ecology

Community Ecology

Biodiversity and Conservation Biology

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