Question 1

What causes the decrease in the amount of cyclin at a specific point in the cell cycle?

Accepted Answer

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 Cdk 
E) the binding of PDGF to receptors on the cell surface 
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 Cdk 
E) the binding of PDGF to receptors on the cell surface

Question 2

After which checkpoint is the cell first committed to continue the cell cycle through M?

Accepted Answer

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

Question 3

The following questions are based on the following figure.
  
-G₁ is represented by which numbered part(s)of the cycle?

Accepted Answer

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

Question 4

Why do chromosomes coil during mitosis?

Accepted Answer

A) to increase their potential energy 
B) to allow the chromosomes to move without becoming entangled and breaking 
C) to allow the chromosomes to fit within the nuclear envelope 
D) to allow the sister chromatids to remain attached 
E) to provide for the structure of the centromere 
A) to increase their potential energy 
B) to allow the chromosomes to move without becoming entangled and breaking 
C) to allow the chromosomes to fit within the nuclear envelope 
D) to allow the sister chromatids to remain attached 
E) to provide for the structure of the centromere

Question 5

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 6

A research team began a study of a cultured cell line.Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence.What could they conclude right away?

Accepted Answer

A) The cells originated in the nervous system. 
B) The cells are unable to form spindle microtubules. 
C) They have altered series of cell cycle phases. 
D) The cells show characteristics of tumours. 
E) They were originally derived from an elderly organism. 
A) The cells originated in the nervous system. 
B) The cells are unable to form spindle microtubules. 
C) They have altered series of cell cycle phases. 
D) The cells show characteristics of tumours. 
E) They were originally derived from an elderly organism.

Question 7

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 8

Scientists isolate cells in various phases of the cell cycle.They find a group of cells that have 1.5 times more DNA than G₁ phase cells.What phase of the cell cycle are these cells in?

Accepted Answer

A) between the G₁ and S phase 
B) G₂ 
C) M 
D) S 
E) Between G₂ and M 
A) between the G₁ and S phase 
B) G₂ 
C) M 
D) S 
E) Between G₂ and M

Question 9

Which of the following is a function of those spindle microtubules that do not attach to kinetochores?

Accepted Answer

A) maintaining an appropriate spacing among the moving chromosomes 
B) producing a cleavage furrow when telophase is complete 
C) providing the ATP needed by the fibres attached to kinetochores 
D) maintaining the region of overlap of microtubules in the cell's center 
E) pulling the poles of the spindles closer to one another 
A) maintaining an appropriate spacing among the moving chromosomes 
B) producing a cleavage furrow when telophase is complete 
C) providing the ATP needed by the fibres attached to kinetochores 
D) maintaining the region of overlap of microtubules in the cell's center 
E) pulling the poles of the spindles closer to one another

Question 10

Which of the following eukaryotic proteins appear to have related proteins involved in binary fission?

Accepted Answer

A) cyclins 
B) Cdks 
C) MPF 
D) actin and tubulin 
E) cohesins 
A) cyclins 
B) Cdks 
C) MPF 
D) actin and tubulin 
E) cohesins

Question 11

Which of the following most accurately describes a cyclin?

Accepted Answer

A) It is present in similar concentrations throughout the cell cycle. 
B) It is activated to phosphorylate by complexing with a Cdk. 
C) It decreases in concentration when MPF activity increases. 
D) It activates a Cdk molecule when it is in sufficient concentration. 
E) It activates a Cdk when its concentration is decreased. 
A) It is present in similar concentrations throughout the cell cycle. 
B) It is activated to phosphorylate by complexing with a Cdk. 
C) It decreases in concentration when MPF activity increases. 
D) It activates a Cdk molecule when it is in sufficient concentration. 
E) It activates a Cdk when its concentration is decreased.

Question 12

Exposure of zebrafish nuclei to meiotic cytosol resulted in phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2.NEP55 is a protein of the inner nuclear membrane,and L68 is a protein of the nuclear lamina.What is the most likely role of phosphorylation of these proteins in the process of mitosis?

Accepted Answer

A) They enable the attachment of the spindle microtubules to kinetochore regions of the centromere. 
B) They are involved in the disassembly and dispersal of the nucleolus. 
C) They are involved in the disassembly of the nuclear envelope. 
D) They assist in the movement of the centrosomes to opposite sides of the nucleus. 
E) They are part of the kinetochore. 
A) They enable the attachment of the spindle microtubules to kinetochore regions of the centromere. 
B) They are involved in the disassembly and dispersal of the nucleolus. 
C) They are involved in the disassembly of the nuclear envelope. 
D) They assist in the movement of the centrosomes to opposite sides of the nucleus. 
E) They are part of the kinetochore.

Question 13

Density-dependent inhibition depends on the binding of a cell-surface protein to its counterpart on an adjoining cell's surface.A growth inhibiting signal is sent to both cells,preventing them from dividing.Certain external physical factors can affect this inhibition mechanism.Select the statement that makes a correct prediction about natural phenomena that could occur during the cell cycle to prevent cell growth.

Accepted Answer

A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to allow cell growth. 
B) As cells become more numerous, the protein kinases they produce begin to compete with each other until only one cell has the proteins necessary for growth. 
C) As cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth. 
D) As cells become more numerous, more and more of them enter the synthesis part of the cell cycle and duplicate DNA to inhibit cell growth. 
E) As cells become more numerous, they can detect the DNA fragments outside the cell. 
A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to allow cell growth. 
B) As cells become more numerous, the protein kinases they produce begin to compete with each other until only one cell has the proteins necessary for growth. 
C) As cells become more numerous, the amount of required growth factors and nutrients per cell becomes insufficient to allow for cell growth. 
D) As cells become more numerous, more and more of them enter the synthesis part of the cell cycle and duplicate DNA to inhibit cell growth. 
E) As cells become more numerous, they can detect the DNA fragments outside the cell.

Question 14

FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis.What is its function 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 
E) the aster in 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 
E) the aster in eukaryotic cells

Question 15

Use the following information to answer the questions below.
The lettered circle in the figure below 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 grey.The chromosomes in the unlettered circle have not yet replicated.Choose the correct chromosomal conditions for the following stages.
  
-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

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. 
E) Plant cells undertake cytokinesis during anaphase; animal cells undertake cytokinesis during telophase. 
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. 
E) Plant cells undertake cytokinesis during anaphase; animal cells undertake cytokinesis during telophase.

Question 17

In which group of eukaryotic organisms does the nuclear envelope remain intact during mitosis?

Accepted Answer

A) seedless plants 
B) dinoflagellates 
C) diatoms 
D) dinoflagellates and diatoms only 
E) seedless plants, dinoflagellates, and diatoms 
A) seedless plants 
B) dinoflagellates 
C) diatoms 
D) dinoflagellates and diatoms only 
E) seedless plants, dinoflagellates, and diatoms

Question 18

A particular cyclin called cyclin E forms a complex with Cdk 2 (cyclin-dependent kinase 2).This complex is important for the progression of the cell from G₁ into the S phase of the cell cycle.Which of the following statements is correct?

Accepted Answer

A) The amount of free cyclin E is greatest during the S phase. 
B) The amount of free Cdk 2 is greater during G₁ compared to the S phase. 
C) The amount of free cyclin E is highest during G₁. 
D) The amount of free Cdk 2 is greatest during G₁. 
E) The activity of the cyclin E/Cdk 2 complex is highest during G₂. 
A) The amount of free cyclin E is greatest during the S phase. 
B) The amount of free Cdk 2 is greater during G₁ compared to the S phase. 
C) The amount of free cyclin E is highest during G₁. 
D) The amount of free Cdk 2 is greatest during G₁. 
E) The activity of the cyclin E/Cdk 2 complex is highest during G₂.

Question 19

Nucleotides can be radiolabelled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation.In a set of experiments,a student-faculty research team used labelled T nucleotides and introduced these into the culture of dividing human cells at specific times.
-Once they had determined which cells were dividing,the team wanted to use a non-radioactive method to track whether various physiological factors (such as food or body temperature)affected the action of the pathogen.Which of the following would be effective,simple,and safe?

Accepted Answer

A) measuring picograms of DNA 
B) measuring numbers of chromosomes 
C) measuring numbers of chromatids 
D) counting the frequency of cells in mitosis 
E) counting newly formed plasma membranes 
A) measuring picograms of DNA 
B) measuring numbers of chromosomes 
C) measuring numbers of chromatids 
D) counting the frequency of cells in mitosis 
E) counting newly formed plasma membranes

Question 20

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.

Exam 12: The Cell Cycle

What causes the decrease in the amount of cyclin at a specific point in the cell cycle?

After which checkpoint is the cell first committed to continue the cell cycle through M?

The following questions are based on the following figure. -G₁ is represented by which numbered part(s)of the cycle?

Why do chromosomes coil during mitosis?

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?

A research team began a study of a cultured cell line.Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence.What could they conclude right away?

The centromere is a region in which

Scientists isolate cells in various phases of the cell cycle.They find a group of cells that have 1.5 times more DNA than G₁ phase cells.What phase of the cell cycle are these cells in?

Which of the following is a function of those spindle microtubules that do not attach to kinetochores?

Which of the following eukaryotic proteins appear to have related proteins involved in binary fission?

Which of the following most accurately describes a cyclin?

FtsZ is a bacterial cytoskeletal protein that forms a contractile ring involved in bacterial cytokinesis.What is its function analogous to?

How is plant cell cytokinesis different from animal cell cytokinesis?

In which group of eukaryotic organisms does the nuclear envelope remain intact during mitosis?

A particular cyclin called cyclin E forms a complex with Cdk 2 (cyclin-dependent kinase 2).This complex is important for the progression of the cell from G₁ into the S phase of the cell cycle.Which of the following statements is correct?

For anaphase to begin,which of the following must occur?

Introduction: Evolution and Themes of Biology

The Chemical Context of Life

Water and Life

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 and Fermentation

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

Regulation of Gene Expression

Viruses

DNA Tools and 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 Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure,Growth,and Development

Resource Acquisition and 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 Signalling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behaviour

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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