Question 1

How might spindle microtubules assist in the process of splitting centromeres?

Accepted Answer

A) the use of motor proteins to split the centromere at specific arginine residues 
B) creating tension by pulling toward opposite poles 
C) coding for enzymes involved in the process 
D) phosphorylating the centromere,which changes its conformation 
A) the use of motor proteins to split the centromere at specific arginine residues 
B) creating tension by pulling toward opposite poles 
C) coding for enzymes involved in the process 
D) phosphorylating the centromere,which changes its conformation

Question 2

The M-phase checkpoint is designed to make sure all chromosomes are attached to the mitotic spindle.If this fails to happen,in which stage of mitosis would the cells be most likely to arrest?

Accepted Answer

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

Question 3

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

Accepted Answer

A) Nothing happens. 
B) Fertilization occurs. 
C) The cells enter mitosis. 
D) Cell differentiation is triggered. 
A) Nothing happens. 
B) Fertilization occurs. 
C) The cells enter mitosis. 
D) Cell differentiation is triggered.

Question 4

Which of the following is not an effect of mitosis-promoting factor (MPF)involved in moving a cell into M phase?

Accepted Answer

A) phosphorylation of lamins,initiating breakdown of the nuclear membrane 
B) phosphorylation of microtubule associated proteins,triggering the formation of the mitotic spindle 
C) phosphorylation of an enzyme that breaks down the cyclin molecule 
D) degradation of cyclin-dependent kinase 
A) phosphorylation of lamins,initiating breakdown of the nuclear membrane 
B) phosphorylation of microtubule associated proteins,triggering the formation of the mitotic spindle 
C) phosphorylation of an enzyme that breaks down the cyclin molecule 
D) degradation of cyclin-dependent kinase

Question 5

Once researchers understood that chromosomes are moved by the spindle microtubules,the next question they wanted to answer is how the microtubules function to bring about this process.They used fluorescent labels to make the chromosomes and the microtubular structures fluoresce.When anaphase began (centromeres split),they photobleached a section of microtubules.As chromosomes moved toward the poles of the daughter cells,the photobleached sections of the microtubules remained stationary.This result suggests that

Accepted Answer

A) the microtubules elongate and shorten at the centrosome end. 
B) the microtubules overlap and slide with respect to each other,effectively shortening the microtubules without depolymerizing the actual fiber. 
C) the microtubules elongate and shorten at their kinetochore end. 
D) the microtubules are of constant length;centrosomes move farther apart to separate chromosomes. 
A) the microtubules elongate and shorten at the centrosome end. 
B) the microtubules overlap and slide with respect to each other,effectively shortening the microtubules without depolymerizing the actual fiber. 
C) the microtubules elongate and shorten at their kinetochore end. 
D) the microtubules are of constant length;centrosomes move farther apart to separate chromosomes.

Question 6

Which of the following is NOT a result of mitosis?

Accepted Answer

A) in fungi,haploid spores are produced from a diploid zygote 
B) germination of a new plant from a seed 
C) asexual reproduction of haploid yeast cells 
D) regeneration of a zebrafish fin 
E) all of the above are examples where mitosis occurs 
A) in fungi,haploid spores are produced from a diploid zygote 
B) germination of a new plant from a seed 
C) asexual reproduction of haploid yeast cells 
D) regeneration of a zebrafish fin 
E) all of the above are examples where mitosis occurs

Question 7

DNA is composed of four nucleosides: adenosine,cytidine,thymidine,and guanosine.If scientists introduced radioactive thymidine into the growth medium of the cells,it would be incorporated into the DNA molecule

Accepted Answer

A) at any point in the cell cycle. 
B) when centromeres split so the two chromosomes can be separated. 
C) during DNA replication. 
D) as the cell enters G₁ of interphase. 
A) at any point in the cell cycle. 
B) when centromeres split so the two chromosomes can be separated. 
C) during DNA replication. 
D) as the cell enters G₁ of interphase.

Question 8

The term contact inhibition refers to the

Accepted Answer

A) exchange of signals between cells using cell surface receptions. 
B) cessation of cell growth when two cells touch each other. 
C) action of non-competitive inhibitors on the catalytic activity of enzymes. 
A) exchange of signals between cells using cell surface receptions. 
B) cessation of cell growth when two cells touch each other. 
C) action of non-competitive inhibitors on the catalytic activity of enzymes.

Question 9

At which stage does chromosome organization change from diffuse/uncondensed to a compact/condensed state?

Accepted Answer

A) Prophase 
B) Metaphase 
C) Interphase 
D) Anaphase 
E) Telophase 
A) Prophase 
B) Metaphase 
C) Interphase 
D) Anaphase 
E) Telophase

Question 10

Which cytoskeletal proteins are important constituents of the contractile structures that form the cleavage furrows involved in animal cell cytokinesis?

Accepted Answer

A) actin 
B) dynein 
C) tubulin 
D) elastin 
A) actin 
B) dynein 
C) tubulin 
D) elastin

Question 11

In a culture of cells,it is observed that the cell cycle has arrested (stopped)during the G1 phase.The reason for this could be that

Accepted Answer

A) not all chromosomes have been replicated. 
B) not all components needed for mitosis are present. 
C) not all components needed for DNA replication are present. 
D) not all chromosomes are attached to mitotic spindles. 
A) not all chromosomes have been replicated. 
B) not all components needed for mitosis are present. 
C) not all components needed for DNA replication are present. 
D) not all chromosomes are attached to mitotic spindles.

Question 12

Metaphase occurs prior to the splitting of centromeres.It is characterized by

Accepted Answer

A) aligning of chromosomes on the equator. 
B) duplication of centrioles. 
C) cytokinesis. 
D) disassembly of the nuclear envelope. 
A) aligning of chromosomes on the equator. 
B) duplication of centrioles. 
C) cytokinesis. 
D) disassembly of the nuclear envelope.

Question 13

Another term that could be used to describe the process of binary fission is

Accepted Answer

A) genetic recombination. 
B) fusion. 
C) recombination. 
D) cloning. 
A) genetic recombination. 
B) fusion. 
C) recombination. 
D) cloning.

Question 14

Regulatory proteins that serve to prevent a cell from entering the S phase under conditions of DNA damage are also known as

Accepted Answer

A) cyclins. 
B) cyclin-dependent kinases. 
C) antibodies. 
D) tumor suppressors. 
A) cyclins. 
B) cyclin-dependent kinases. 
C) antibodies. 
D) tumor suppressors.

Question 15

In the process of chromosome separation,how do microtubules maintain contact with the kinetochores and shorten at the same time?

Accepted Answer

A) Motor proteins move chromosomes down the microtubular structures of the mitotic spindle. 
B) Actin microfilaments cause the microtubular proteins to slide past each other. 
C) The centrosomes move apart,so the microtubular proteins do not need to shorten. 
D) The centrosomes cause the shortening and depolymerization of the microtubular proteins. 
A) Motor proteins move chromosomes down the microtubular structures of the mitotic spindle. 
B) Actin microfilaments cause the microtubular proteins to slide past each other. 
C) The centrosomes move apart,so the microtubular proteins do not need to shorten. 
D) The centrosomes cause the shortening and depolymerization of the microtubular proteins.

Question 16

Researchers pulsed rapidly dividing cultured cells for 30 minutes with radioactive thymidine.The cells were then exposed to a solution containing non-radiolabeled thymidine.Cells were analyzed at 2-hour intervals.At the 2-hour time point,no cells appeared to be dividing.Only after 4 hours did some labeled cells appear to be in M phase.This result can be explained in the following way:

Accepted Answer

A) Cultured cells all divide at the same time,and none synthesized DNA during the 30-minute labeling period. 
B) The cells were arrested in a nondividing state because of the treatment and could not enter M phase until several hours after the label was removed. 
C) Synthesis (S)phase is lengthy-about 12 hours in most cell types-and the radioactive thymidine was not present long enough for most cells to be labeled. 
D) There seems to be a gap or a lag in the cell cycle,between the synthesis of DNA and cell division. 
A) Cultured cells all divide at the same time,and none synthesized DNA during the 30-minute labeling period. 
B) The cells were arrested in a nondividing state because of the treatment and could not enter M phase until several hours after the label was removed. 
C) Synthesis (S)phase is lengthy-about 12 hours in most cell types-and the radioactive thymidine was not present long enough for most cells to be labeled. 
D) There seems to be a gap or a lag in the cell cycle,between the synthesis of DNA and cell division.

Question 17

Cancer-causing mutated tumour suppressor genes result from which of the following?

Accepted Answer

A) programmed cell death 
B) mutations in genes encoding proteins that normally inhibit progression through the cell cycle 
C) mutations that cause overexpression of genes encoding proteins that normally stimulate progression through the cell cycle 
D) cell-contact inhibition 
A) programmed cell death 
B) mutations in genes encoding proteins that normally inhibit progression through the cell cycle 
C) mutations that cause overexpression of genes encoding proteins that normally stimulate progression through the cell cycle 
D) cell-contact inhibition

Question 18

In human and many other eukaryotic species' cells,the nuclear membrane has to disappear in order for what to take place?

Accepted Answer

A) cytokinesis 
B) attachment of mitotic spindle to kinetochores 
C) splitting of the centrosomes 
D) disassembly of the nucleolus 
A) cytokinesis 
B) attachment of mitotic spindle to kinetochores 
C) splitting of the centrosomes 
D) disassembly of the nucleolus

Question 19

A parent cell divides to form two genetically identical daughter cells in the process of mitosis.For mitosis to take place

Accepted Answer

A) the parent cell must first be fertilized. 
B) the parent cell must replicate its entire genome prior to mitosis. 
C) the parent cell must reproduce its DNA during telophase. 
D) the parent cell must divide its DNA in half so each daughter cell gets only the genes needed to carry out its functions.In this way,differentiation occurs. 
A) the parent cell must first be fertilized. 
B) the parent cell must replicate its entire genome prior to mitosis. 
C) the parent cell must reproduce its DNA during telophase. 
D) the parent cell must divide its DNA in half so each daughter cell gets only the genes needed to carry out its functions.In this way,differentiation occurs.

Exam 11: The Cell Cycle

How might spindle microtubules assist in the process of splitting centromeres?

The M-phase checkpoint is designed to make sure all chromosomes are attached to the mitotic spindle.If this fails to happen,in which stage of mitosis would the cells be most likely to arrest?

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

Which of the following is not an effect of mitosis-promoting factor (MPF)involved in moving a cell into M phase?

Which of the following is NOT a result of mitosis?

DNA is composed of four nucleosides: adenosine,cytidine,thymidine,and guanosine.If scientists introduced radioactive thymidine into the growth medium of the cells,it would be incorporated into the DNA molecule

The term contact inhibition refers to the

At which stage does chromosome organization change from diffuse/uncondensed to a compact/condensed state?

Which cytoskeletal proteins are important constituents of the contractile structures that form the cleavage furrows involved in animal cell cytokinesis?

In a culture of cells,it is observed that the cell cycle has arrested (stopped)during the G1 phase.The reason for this could be that

Metaphase occurs prior to the splitting of centromeres.It is characterized by

Another term that could be used to describe the process of binary fission is

Regulatory proteins that serve to prevent a cell from entering the S phase under conditions of DNA damage are also known as

In the process of chromosome separation,how do microtubules maintain contact with the kinetochores and shorten at the same time?

Cancer-causing mutated tumour suppressor genes result from which of the following?

In human and many other eukaryotic species' cells,the nuclear membrane has to disappear in order for what to take place?

A parent cell divides to form two genetically identical daughter cells in the process of mitosis.For mitosis to take place

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

Lipids, membranes, and the First Cells

Inside the Cell

Cell-Cell Interactions

Cellular Respiration and Fermentation

Photosynthesis

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

Analyzing and Engineering Genes

Genomics

Principles of Development

An Introduction to Animal Development

An Introduction to Plant Development

Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

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Protists

Green Algae and Land Plants

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An Introduction to Animals

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Viruses

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Water and Sugar Transport in Plants

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Plant Sensory Systems, signals, and Responses

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Animal Form and Function

Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Electrical Signals in Animals

Animal Sensory Systems and Movement

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