D2.1 Cell and nuclear division

A two-cell sea urchin (Echinoidea) embryo was physically separated by scientists into two cells. Each cell, through further embryonic development, became an adult sea urchin.

[Source: Clker-Free-Vector-Images/Pixabay.]

What is the relationship between the two adult sea urchins?

A. They are equivalent to non-identical twins.

B. Half of the genes would be the same.

C. Both adults would have haploid cells.

D. They are clones.

By referring to both graphs, evaluate the hypothesis that vinblastine targets cells in mitosis and prevents them from completing the process.

A two-cell sea urchin (Echinoidea) embryo was physically separated by scientists into two cells. Each cell, through further embryonic development, became an adult sea urchin.

[Source: Clker-Free-Vector-Images/Pixabay.]

What is the relationship between the two adult sea urchins?

A. They are equivalent to non-identical twins.

B. Half of the genes would be the same.

C. Both adults would have haploid cells.

D. They are clones.

By referring to both graphs, evaluate the hypothesis that vinblastine targets cells in mitosis and prevents them from completing the process.

By referring to both graphs, evaluate the hypothesis that vinblastine targets cells in mitosis and prevents them from completing the process.

Explain the need for halving the chromosome number during a sexual life cycle and how this is done.

Distinguish between the outcomes of a cell dividing either by mitosis or meiosis.

Explain the need for halving the chromosome number during a sexual life cycle and how this is done.

Explain the need for halving the chromosome number during a sexual life cycle and how this is done.

Distinguish between the outcomes of a cell dividing either by mitosis or meiosis.

Distinguish between the outcomes of a cell dividing either by mitosis or meiosis.

Using the letter C, label the stage on the diagram where chromosome supercoiling occurs.

Using the letter M, label the stage on the diagram where sister chromatids migrate to opposite poles.

Using the letter C, label the stage on the diagram where chromosome supercoiling occurs.

Using the letter M, label the stage on the diagram where sister chromatids migrate to opposite poles.

Using the letter C, label the stage on the diagram where chromosome supercoiling occurs.

Using the letter M, label the stage on the diagram where sister chromatids migrate to opposite poles.

Identify, with a reason, the stage shown at X.

Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]

In the micrograph, which letter points to a cell in anaphase?

[Source: Berkshire Community College Bioscience Image Library,
https://commons.wikimedia.org/wiki/File:Mitotic_Stages_in_Apical_Meristem_of_Allium_Root_Tip_(36762516673).jpg,
licensed under Creative Commons CC0 1.0 Universal Public Domain Dedication]

The image shows a micrograph of a cell.

[Source: © 2014, https://commons.wikimedia.org/wiki/File:Mitosis_(261_13)_Pressed;_root_meristem_of_onion_(cells_
in_prophase,_metaphase,_anaphase,_telophase).jpg by Doc. RNDr. Josef Reischig, CSc.]

What explains the appearance of the cell in the micrograph?

A. The cell is dying.

B. The DNA is replicating.

C. The cell is in metaphase.

D. The cell is in telophase.

Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]

The diagram shows a stage in cell division.

[Source: © International Baccalaureate Organization 2019]

What is the stage shown?

A. Anaphase I of mitosis

B. Anaphase II of mitosis

C. Anaphase I of meiosis

D. Anaphase II of meiosis

The image shows a cell from the root tip of an onion (Allium cepa) (2n = 16) during late prophase of mitosis.

_{[Source: Davidson, M.W. and Molecular Expressions at Florida State University, n.d. Late prophase. [image online]
Available at: https://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html [Accessed 5 October 2021].]}

How many chromatids are present in the cell?

A.  8

B.  16

C.  32

D.  64

The image shows a cell from the root tip of an onion (Allium cepa) (2n = 16) during late prophase of mitosis.

_{[Source: Davidson, M.W. and Molecular Expressions at Florida State University, n.d. Late prophase. [image online]
Available at: https://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html [Accessed 5 October 2021].]}

How many chromatids are present in the cell?

A.  8

B.  16

C.  32

D.  64

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify, with a reason, the stage shown at X.

Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]

Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]

In the micrograph, which letter points to a cell in anaphase?

[Source: Berkshire Community College Bioscience Image Library,
https://commons.wikimedia.org/wiki/File:Mitotic_Stages_in_Apical_Meristem_of_Allium_Root_Tip_(36762516673).jpg,
licensed under Creative Commons CC0 1.0 Universal Public Domain Dedication]

The image shows a micrograph of a cell.

[Source: © 2014, https://commons.wikimedia.org/wiki/File:Mitosis_(261_13)_Pressed;_root_meristem_of_onion_(cells_
in_prophase,_metaphase,_anaphase,_telophase).jpg by Doc. RNDr. Josef Reischig, CSc.]

What explains the appearance of the cell in the micrograph?

A. The cell is dying.

B. The DNA is replicating.

C. The cell is in metaphase.

D. The cell is in telophase.

Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]

Identify the stage of mitosis labelled X in the image, giving a reason.

[Source: Copyright 2002, The Trustees of Indiana University]

The diagram shows a stage in cell division.

[Source: © International Baccalaureate Organization 2019]

What is the stage shown?

A. Anaphase I of mitosis

B. Anaphase II of mitosis

C. Anaphase I of meiosis

D. Anaphase II of meiosis

The image shows a cell from the root tip of an onion (Allium cepa) (2n = 16) during late prophase of mitosis.

_{[Source: Davidson, M.W. and Molecular Expressions at Florida State University, n.d. Late prophase. [image online]
Available at: https://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html [Accessed 5 October 2021].]}

How many chromatids are present in the cell?

A.  8

B.  16

C.  32

D.  64

The image shows a cell from the root tip of an onion (Allium cepa) (2n = 16) during late prophase of mitosis.

_{[Source: Davidson, M.W. and Molecular Expressions at Florida State University, n.d. Late prophase. [image online]
Available at: https://micro.magnet.fsu.edu/micro/gallery/mitosis/mitosis.html [Accessed 5 October 2021].]}

How many chromatids are present in the cell?

A.  8

B.  16

C.  32

D.  64

The image shows tetrads in the anther of a lily. A tetrad is a group of four cells, produced when one mother cell divides by meiosis. The tetrad indicated by the arrow contains a total of 48 chromosomes.

[Source: [Tetrad], 2012. [image online] Available at: https://www.iasprr.org/old/iasprr-pix/lily/tetrad.jpg [accessed: 4 April 2019]. Photo courtesy of Professor Scott D. Russell.]

What is the diploid number of the plant?

A. 12

B. 24

C. 48

D. 96

Outline what occurs in cells in the first division of meiosis.

Testing the chromosomes of a girl with Turner syndrome produced the following karyogram.

[Source: Turner’s syndrome karyotype 45,XO. This female lacks the second X chromosome present in the
normal karyotype. Symptoms include short stature, neck webbing, elbow deformity, widely spaced nipples with shield chest, primary amenorrhea, sexual infantilism and sterility. The ovaries are reduced to fibrous streaks. Also known as XO syndrome or ovarian short-stature syndrome. Credit: Wessex Reg. Genetics Centre. Attribution 4.0 International (CC BY 4.0).]

The condition can result from non-disjunction occurring in anaphase I of meiosis in an egg cell. Two cells result from the first division, one of which would lead to Turner syndrome. Which chromosomes will be in the other cell (polar body) at the end of meiosis I?

A. 44 autosomes and X

B. 44 autosomes and XX

C. 22 autosomes and X

D. 22 autosomes and XX

The micrograph shows a cross section of a lily (Lilium longiflorum) anther.

^{[Source: Sinhyu / iStock.]}

What can be found in X?

A.  Haploid nuclei produced by meiosis

B.  Diploid nuclei produced by fertilization

C.  Haploid nuclei produced by mitosis

D.  Diploid nuclei produced by pollination

The image shows tetrads in the anther of a lily. A tetrad is a group of four cells, produced when one mother cell divides by meiosis. The tetrad indicated by the arrow contains a total of 48 chromosomes.

[Source: [Tetrad], 2012. [image online] Available at: https://www.iasprr.org/old/iasprr-pix/lily/tetrad.jpg [accessed: 4 April 2019]. Photo courtesy of Professor Scott D. Russell.]

What is the diploid number of the plant?

A. 12

B. 24

C. 48

D. 96

Outline what occurs in cells in the first division of meiosis.

Outline what occurs in cells in the first division of meiosis.

Testing the chromosomes of a girl with Turner syndrome produced the following karyogram.

[Source: Turner’s syndrome karyotype 45,XO. This female lacks the second X chromosome present in the
normal karyotype. Symptoms include short stature, neck webbing, elbow deformity, widely spaced nipples with shield chest, primary amenorrhea, sexual infantilism and sterility. The ovaries are reduced to fibrous streaks. Also known as XO syndrome or ovarian short-stature syndrome. Credit: Wessex Reg. Genetics Centre. Attribution 4.0 International (CC BY 4.0).]

The condition can result from non-disjunction occurring in anaphase I of meiosis in an egg cell. Two cells result from the first division, one of which would lead to Turner syndrome. Which chromosomes will be in the other cell (polar body) at the end of meiosis I?

A. 44 autosomes and X

B. 44 autosomes and XX

C. 22 autosomes and X

D. 22 autosomes and XX

The micrograph shows a cross section of a lily (Lilium longiflorum) anther.

^{[Source: Sinhyu / iStock.]}

What can be found in X?

A.  Haploid nuclei produced by meiosis

B.  Diploid nuclei produced by fertilization

C.  Haploid nuclei produced by mitosis

D.  Diploid nuclei produced by pollination

The karyogram shown belongs to a human being.

[Source: Reproduced from Tennakoon J, Kandasamy Y, Alcock G, Koh TH. Edwards syndrome with double trisomy. Singapore Med J. 2008 Jul;49(7):e190-1. PMID: 18695855.]

What can be deduced from this karyogram?

A. The person is a male with Down syndrome.

B. The person is a female with Down syndrome.

C. The person is a male with a genetic disorder.

D. The person is a female with a missing chromosome.

The graph shows the incidence of trisomy resulting from non-disjunction in pregnancies at different maternal ages.

[Source: Center for Disease Control]

What can be inferred from the graph?

A. The incidence of three copies of a chromosome increases directly in proportion with the age of the mother.

B. The incidence of three sets of chromosomes increases from age 20.

C. The incidence of three copies of a chromosome increases the most from age 35.

D. The incidence of three sets of chromosomes increases the most from age 30.

The karyogram shown belongs to a human being.

[Source: Reproduced from Tennakoon J, Kandasamy Y, Alcock G, Koh TH. Edwards syndrome with double trisomy. Singapore Med J. 2008 Jul;49(7):e190-1. PMID: 18695855.]

What can be deduced from this karyogram?

A. The person is a male with Down syndrome.

B. The person is a female with Down syndrome.

C. The person is a male with a genetic disorder.

D. The person is a female with a missing chromosome.

The graph shows the incidence of trisomy resulting from non-disjunction in pregnancies at different maternal ages.

[Source: Center for Disease Control]

What can be inferred from the graph?

A. The incidence of three copies of a chromosome increases directly in proportion with the age of the mother.

B. The incidence of three sets of chromosomes increases from age 20.

C. The incidence of three copies of a chromosome increases the most from age 35.

D. The incidence of three sets of chromosomes increases the most from age 30.

The diagram shows the chromosomes derived from a single homologous pair following meiosis in a diploid cell.

Which diagram represents the homologous pair from which these chromosomes were derived?

[Source: © International Baccalaureate Organization 2019]

At which stage of meiosis are bivalents formed?

A. Interphase

B. Prophase I

C. Prophase II

D. Metaphase II

The diagram shows the chromosomes derived from a single homologous pair following meiosis in a diploid cell.

Which diagram represents the homologous pair from which these chromosomes were derived?

[Source: © International Baccalaureate Organization 2019]

At which stage of meiosis are bivalents formed?

A. Interphase

B. Prophase I

C. Prophase II

D. Metaphase II

Based on the information, suggest with a reason which of the labelled cell types will become more common in Allium root tips treated with ZDV.

Allium root tips continue to show some growth even at high concentrations of NVP. Suggest a possible reason for the growth seen in root tips with 800μmol NVP.

In the chimpanzee (Pan troglodytes), the haploid number of chromosomes is 24. How many sister chromatids are present in the G2 phase of a somatic cell, such as a cell in the bone marrow of the chimpanzee?

A. 12

B. 24

C. 48

D. 96

State processes occurring during interphase.

Using the letter C, label the stage on the diagram where chromosome supercoiling occurs.

Using the letter M, label the stage on the diagram where sister chromatids migrate to opposite poles.

In which stage of the cell cycle are chromosomes duplicated?

Based on the information, suggest with a reason which of the labelled cell types will become more common in Allium root tips treated with ZDV.

Allium root tips continue to show some growth even at high concentrations of NVP. Suggest a possible reason for the growth seen in root tips with 800μmol NVP.

Based on the information, suggest with a reason which of the labelled cell types will become more common in Allium root tips treated with ZDV.

Allium root tips continue to show some growth even at high concentrations of NVP. Suggest a possible reason for the growth seen in root tips with 800μmol NVP.

In the chimpanzee (Pan troglodytes), the haploid number of chromosomes is 24. How many sister chromatids are present in the G2 phase of a somatic cell, such as a cell in the bone marrow of the chimpanzee?

A. 12

B. 24

C. 48

D. 96

State processes occurring during interphase.

Using the letter C, label the stage on the diagram where chromosome supercoiling occurs.

Using the letter M, label the stage on the diagram where sister chromatids migrate to opposite poles.

State processes occurring during interphase.

Using the letter C, label the stage on the diagram where chromosome supercoiling occurs.

Using the letter M, label the stage on the diagram where sister chromatids migrate to opposite poles.

In which stage of the cell cycle are chromosomes duplicated?

State the role of cyclins in the cell cycle.

Explain how changes to the cell cycle can result in tumour formation.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

State the role of cyclins in the cell cycle.

Explain how changes to the cell cycle can result in tumour formation.

Explain how changes to the cell cycle can result in tumour formation.

The graph shows the mitotic index in the roots of lentil plants at different distances from the end of the root.

[Source: Physiologia Plantarum, Volume 105, Issue 1, January 1999, Pages 171–178, Effect of microgravity on the cell cycle
in the lentil root F. Yu, D. Driss-Ecole, J. Rembur, V. Legué, G. Perbal Wiley Online Library: https://onlinelibrary.wiley.
com/doi/abs/10.1034/j.1399-3054.1999.105125.x]

What can be deduced from the graph?

A. As the distance from the end of the root increases, more cells are undergoing mitosis.

B. At 0.5 mm from the end of the root, most of the cells are in prophase.

C. There were fewer cells observed at 1.5 mm than at 0.5 mm.

D. As the distance from the end of the root increases, the percentage of cells in interphase increases.

Discuss one advantage and one disadvantage of using plant tissue to investigate drugs intended to treat cancer in humans.

Advantage:

Disadvantage:

The mitotic index is an important prognostic tool for predicting the response of cancer cells to chemotherapy. Outline how the mitotic index is calculated.

Suggest one difference between tissue taken from a lung cancer tumour and normal lung tissue that might be seen in micrographs.

The graph shows the mitotic index in the roots of lentil plants at different distances from the end of the root.

[Source: Physiologia Plantarum, Volume 105, Issue 1, January 1999, Pages 171–178, Effect of microgravity on the cell cycle
in the lentil root F. Yu, D. Driss-Ecole, J. Rembur, V. Legué, G. Perbal Wiley Online Library: https://onlinelibrary.wiley.
com/doi/abs/10.1034/j.1399-3054.1999.105125.x]

What can be deduced from the graph?

A. As the distance from the end of the root increases, more cells are undergoing mitosis.

B. At 0.5 mm from the end of the root, most of the cells are in prophase.

C. There were fewer cells observed at 1.5 mm than at 0.5 mm.

D. As the distance from the end of the root increases, the percentage of cells in interphase increases.

Discuss one advantage and one disadvantage of using plant tissue to investigate drugs intended to treat cancer in humans.

Advantage:

Disadvantage:

Discuss one advantage and one disadvantage of using plant tissue to investigate drugs intended to treat cancer in humans.

Advantage:

Disadvantage:

The mitotic index is an important prognostic tool for predicting the response of cancer cells to chemotherapy. Outline how the mitotic index is calculated.

The mitotic index is an important prognostic tool for predicting the response of cancer cells to chemotherapy. Outline how the mitotic index is calculated.

Suggest one difference between tissue taken from a lung cancer tumour and normal lung tissue that might be seen in micrographs.

Suggest one difference between tissue taken from a lung cancer tumour and normal lung tissue that might be seen in micrographs.