Question 1

Density-dependent inhibition is explained by which of the following?

Accepted Answer

A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors. 
B) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing. 
C) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbour. 
D) As cells become more numerous, more and more of them enter the S phase of the cell cycle. 
E) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism. 
A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors. 
B) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing. 
C) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbour. 
D) As cells become more numerous, more and more of them enter the S phase of the cell cycle. 
E) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism.

Question 2

A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle.Which of the following would result if colchicine is added to a sample of cells in G₂?

Accepted Answer

A) The cells would immediately die. 
B) The cells would be unable to begin M and stay in G₂. 
C) The chromosomes would coil and shorten but have no spindle to attach to. 
D) The chromosomes would segregate but in a disorderly pattern. 
E) Each resultant daughter cell would also be unable to form a spindle. 
A) The cells would immediately die. 
B) The cells would be unable to begin M and stay in G₂. 
C) The chromosomes would coil and shorten but have no spindle to attach to. 
D) The chromosomes would segregate but in a disorderly pattern. 
E) Each resultant daughter cell would also be unable to form a spindle.

Question 3

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?

Accepted Answer

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

Question 4

Only once all kinetochores are attached to spindle microtubules can ________ proceed.

Accepted Answer

A) metaphase 
B) anaphase 
C) synthesis 
D) MPF 
E) G₀ 
A) metaphase 
B) anaphase 
C) synthesis 
D) MPF 
E) G₀

Question 5

The cyclin component of MPF is destroyed toward the end of which phase?

Accepted Answer

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

Question 6

Using which of the following techniques would enable your lab group to distinguish between a cell in G₂ and a cell from the same organism in G₁?

Accepted Answer

A) fluorescence microscopy 
B) electron microscopy 
C) spectrophotometry 
D) radioactive-labelled nucleotides 
E) labelled kinetochore proteins 
A) fluorescence microscopy 
B) electron microscopy 
C) spectrophotometry 
D) radioactive-labelled nucleotides 
E) labelled kinetochore proteins

Question 7

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 8

At the M phase checkpoint,the complex allows for what to occur?

Accepted Answer

A) Separase enzyme cleaves cohesins and allows chromatids to separate. 
B) Cohesins alter separase to allow chromatids to separate. 
C) Kinetochores are able to bind to spindle microtubules. 
D) All microtubules are made to bind to kinetochores. 
E) Daughter cells are allowed to pass into G₁. 
A) Separase enzyme cleaves cohesins and allows chromatids to separate. 
B) Cohesins alter separase to allow chromatids to separate. 
C) Kinetochores are able to bind to spindle microtubules. 
D) All microtubules are made to bind to kinetochores. 
E) Daughter cells are allowed to pass into G₁.

Question 9

Use the following information to answer the questions below.
You observe cells under the microscope and notice that,while in telophase,small vesicles line up along the middle of the cell.
-You conclude that these cells are

Accepted Answer

A) animal cells. 
B) plant cells. 
C) bacteria. 
D) diatoms. 
E) tumour cells. 
A) animal cells. 
B) plant cells. 
C) bacteria. 
D) diatoms. 
E) tumour cells.

Question 10

Use the data in the table below 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.
   
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 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. 
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.

Question 11

What is the mitotic spindle involved in?

Accepted Answer

A) cytokinesis 
B) triggering the compaction and condensation of chromosomes 
C) dissolving the nuclear membrane 
D) separation of sister chromatids 
E) replication of DNA 
A) cytokinesis 
B) triggering the compaction and condensation of chromosomes 
C) dissolving the nuclear membrane 
D) separation of sister chromatids 
E) replication of DNA

Question 12

Which of the following best describes how chromosomes move toward the poles of the spindle during mitosis?

Accepted Answer

A) The chromosomes are "reeled in" by the contraction of spindle microtubules. 
B) Motor proteins of the kinetochores move the chromosomes along the spindle microtubules. 
C) Nonkinetochore spindle fibres serve to push chromosomes in the direction of the poles. 
D) The chromosomes are "reeled in" by the contraction of spindle microtubules, and motor proteins of the kinetochores move the chromosomes along the spindle microtubules. 
E) The chromosomes are "reeled in" by the contraction of spindle microtubules, motor proteins of the kinetochores move the chromosomes along the spindle microtubules, and nonkinetochore spindle fibres serve to push chromosomes in the direction of the poles. 
A) The chromosomes are "reeled in" by the contraction of spindle microtubules. 
B) Motor proteins of the kinetochores move the chromosomes along the spindle microtubules. 
C) Nonkinetochore spindle fibres serve to push chromosomes in the direction of the poles. 
D) The chromosomes are "reeled in" by the contraction of spindle microtubules, and motor proteins of the kinetochores move the chromosomes along the spindle microtubules. 
E) The chromosomes are "reeled in" by the contraction of spindle microtubules, motor proteins of the kinetochores move the chromosomes along the spindle microtubules, and nonkinetochore spindle fibres serve to push chromosomes in the direction of the poles.

Question 13

Use the following information to answer the questions below.
You observe cells under the microscope and notice that,while in telophase,small vesicles line up along the middle of the cell.
-Through a microscope,you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate.This cell is most likely

Accepted Answer

A) an animal cell in the process of cytokinesis. 
B) a plant cell in the process of cytokinesis. 
C) an animal cell in the S phase of the cell cycle. 
D) a bacterial cell dividing. 
E) a plant cell in metaphase. 
A) an animal cell in the process of cytokinesis. 
B) a plant cell in the process of cytokinesis. 
C) an animal cell in the S phase of the cell cycle. 
D) a bacterial cell dividing. 
E) a plant cell in metaphase.

Question 14

What happens if MPF (mitosis-promoting factor)is introduced into immature frog oocytes that are arrested in G₂?

Accepted Answer

A) Nothing happens. 
B) The cells undergo meiosis. 
C) The cells enter mitosis. 
D) Cell differentiation is triggered. 
E) The cells enter S phase. 
A) Nothing happens. 
B) The cells undergo meiosis. 
C) The cells enter mitosis. 
D) Cell differentiation is triggered. 
E) The cells enter S phase.

Question 15

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.

Question 16

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 17

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 at the 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 18

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

Accepted Answer

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

Question 19

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) When they stop dividing, they do so at random points in the cell cycle, and they are not subject to cell cycle controls. 
E) When they stop dividing, they do so at random points in the cell cycle; they are not subject to cell cycle controls; and they do not exhibit density-dependent inhibition when grown in culture. 
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) When they stop dividing, they do so at random points in the cell cycle, and they are not subject to cell cycle controls. 
E) When they stop dividing, they do so at random points in the cell cycle; they are not subject to cell cycle controls; and they do not exhibit density-dependent inhibition when grown in culture.

Question 20

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.
-Which of the following questions might be answered by such a method?

Accepted Answer

A) How many cells are produced by the culture per hour? 
B) What is the length of the S phase of the cell cycle? 
C) When is the S chromosome synthesized? 
D) How many picograms of DNA are made per cell cycle? 
E) When do spindle fibres attach to chromosomes? 
A) How many cells are produced by the culture per hour? 
B) What is the length of the S phase of the cell cycle? 
C) When is the S chromosome synthesized? 
D) How many picograms of DNA are made per cell cycle? 
E) When do spindle fibres attach to chromosomes?

Exam 12: The Cell Cycle

Density-dependent inhibition is explained by which of the following?

A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle.Which of the following would result if colchicine is added to a sample of cells in G₂?

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?

Only once all kinetochores are attached to spindle microtubules can ________ proceed.

The cyclin component of MPF is destroyed toward the end of which phase?

Using which of the following techniques would enable your lab group to distinguish between a cell in G₂ and a cell from the same organism in G₁?

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

At the M phase checkpoint,the complex allows for what to occur?

Use the following information to answer the questions below. You observe cells under the microscope and notice that,while in telophase,small vesicles line up along the middle of the cell. -You conclude that these cells are

What is the mitotic spindle involved in?

Which of the following best describes how chromosomes move toward the poles of the spindle during mitosis?

What happens if MPF (mitosis-promoting factor)is introduced into immature frog oocytes that are arrested in G₂?

The MPF protein complex turns itself off by

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

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

Which of the following is true concerning cancer cells?

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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