D. Continuity and Change

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the role of three enzymes used in the replication of DNA.

Describe how DNA profiling can be used to establish paternity.

This DNA sequence was used to synthesize a polypeptide.

DNA (sense strand): 3′ T A C T G A 5′

DNA (template strand): 5′ A T G A C T 3′

Which are the bases of the tRNA (anticodons)?

A. T A C   T G A

B. U A C   U G A

C. A U G   A C U

D. A T G   A C T

Describe the function of three named enzymes involved in DNA replication.

What is the reason for Taq DNA polymerase being used in the polymerase chain reaction (PCR)?

A. It does not denature at high temperatures.

B. It produces Okazaki fragments more rapidly.

C. It allows translation to proceed rapidly.

D. It works efficiently with helicase in PCR.

Outline the process of DNA profiling.

Outline the role of DNA polymerase III in DNA replication.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

Describe the processes that are carried out by enzymes that bind to DNA.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the conclusions that can be drawn from the data in the graph for the group of aphids fed for three generations on transgenic thale cress plants (T).

Outline the role of three enzymes used in the replication of DNA.

Outline the role of three enzymes used in the replication of DNA.

Describe how DNA profiling can be used to establish paternity.

Describe how DNA profiling can be used to establish paternity.

This DNA sequence was used to synthesize a polypeptide.

DNA (sense strand): 3′ T A C T G A 5′

DNA (template strand): 5′ A T G A C T 3′

Which are the bases of the tRNA (anticodons)?

A. T A C   T G A

B. U A C   U G A

C. A U G   A C U

D. A T G   A C T

Describe the function of three named enzymes involved in DNA replication.

Describe the function of three named enzymes involved in DNA replication.

What is the reason for Taq DNA polymerase being used in the polymerase chain reaction (PCR)?

A. It does not denature at high temperatures.

B. It produces Okazaki fragments more rapidly.

C. It allows translation to proceed rapidly.

D. It works efficiently with helicase in PCR.

Outline the process of DNA profiling.

Outline the role of DNA polymerase III in DNA replication.

Outline the process of DNA profiling.

Outline the role of DNA polymerase III in DNA replication.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

What is a reason that Taq polymerase is a suitable enzyme for use in the polymerase chain reaction (PCR)?

A.  It can work at a wide range of pH.

B.  It works at higher temperatures than most enzymes.

C.  It can separate two strands of DNA.

D.  It allows DNA to be replicated without the use of primers.

Describe the processes that are carried out by enzymes that bind to DNA.

Describe the processes that are carried out by enzymes that bind to DNA.

Outline the role of tRNA in hemoglobin synthesis.

Explain how polypeptides are produced by the process of translation.

DNA has regions that do not code for proteins. State two functions of these regions.

1.

2.

This DNA sequence was used to synthesize a polypeptide.

DNA (sense strand): 3′ T A C T G A 5′

DNA (template strand): 5′ A T G A C T 3′

Which are the bases of the tRNA (anticodons)?

A. T A C   T G A

B. U A C   U G A

C. A U G   A C U

D. A T G   A C T

Outline how a protein is made in a cell by the process of translation.

The diagram shows the three-dimensional structure of tRNA.

[Source: Structure reproduced with the kind permission of N.R. Voss.]

What can attach to the region marked X?

A. mRNA

B. An amino acid

C. An anticodon

D. The P site of the ribosome

What is a feature of transcription in the single-celled organism shown in the electron micrograph?

[Source: George E. Palade Electron Microscopy Slide Collection Harvey Cushing/John Hay Whitney Medical Library Yale University Library.]

A. mRNA splicing

B. Removal of introns

C. Codon-anticodon binding

D. Synthesis of RNA in a 5′ to 3′ direction

The diagram represents transcription and translation.

[Source: © International Baccalaureate Organization 2020.]

What structures do the letters X and Y represent?

The diagram shows mRNA codons.

[Source: elementix / Alamy Stock Photo]

The mRNA sequence UGGAACGUA codes for what amino acid sequence?

A. Glycine-Glutamine-Methionine

B. Methionine-Glutamine-Glycine

C. Threonine-Valine-Histidine

D. Tryptophan-Asparagine-Valine

Explain transcription.

The diagram shows the arrangement of introns and exons in a segment of pre-mRNA. Pre-mRNA is immature mRNA containing introns and exons.

Which is a mature mRNA molecule derived from the pre-mRNA by splicing?

[Source: © International Baccalaureate Organization 2019]

Explain how a single base substitution mutation in DNA can cause a change to a protein.

The diagram illustrates some of the processes involved in DNA replication.

[Source: Rohrmann, G., 2019. AcMNPV DNA replication. [diagram online] Available at:
https://www.ncbi.nlm.nih.gov/books/NBK543453/figure/ch05.F1/ [Accessed 26 October 2021].]

What is shown in the diagram?

A.  DNA polymerase bonding nucleotides in a 3’ to 5’ direction

B.  Single-stranded DNA-binding proteins on the old strands

C.  Gyrase reforming the double helix

D.  DNA ligase joining Okazaki fragments in the leading strand

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Outline the role of tRNA in hemoglobin synthesis.

Explain how polypeptides are produced by the process of translation.

Explain how polypeptides are produced by the process of translation.

DNA has regions that do not code for proteins. State two functions of these regions.

1.

2.

DNA has regions that do not code for proteins. State two functions of these regions.

1.

2.

This DNA sequence was used to synthesize a polypeptide.

DNA (sense strand): 3′ T A C T G A 5′

DNA (template strand): 5′ A T G A C T 3′

Which are the bases of the tRNA (anticodons)?

A. T A C   T G A

B. U A C   U G A

C. A U G   A C U

D. A T G   A C T

Outline how a protein is made in a cell by the process of translation.

Outline how a protein is made in a cell by the process of translation.

The diagram shows the three-dimensional structure of tRNA.

[Source: Structure reproduced with the kind permission of N.R. Voss.]

What can attach to the region marked X?

A. mRNA

B. An amino acid

C. An anticodon

D. The P site of the ribosome

What is a feature of transcription in the single-celled organism shown in the electron micrograph?

[Source: George E. Palade Electron Microscopy Slide Collection Harvey Cushing/John Hay Whitney Medical Library Yale University Library.]

A. mRNA splicing

B. Removal of introns

C. Codon-anticodon binding

D. Synthesis of RNA in a 5′ to 3′ direction

The diagram represents transcription and translation.

[Source: © International Baccalaureate Organization 2020.]

What structures do the letters X and Y represent?

The diagram shows mRNA codons.

[Source: elementix / Alamy Stock Photo]

The mRNA sequence UGGAACGUA codes for what amino acid sequence?

A. Glycine-Glutamine-Methionine

B. Methionine-Glutamine-Glycine

C. Threonine-Valine-Histidine

D. Tryptophan-Asparagine-Valine

Explain transcription.

Explain transcription.

The diagram shows the arrangement of introns and exons in a segment of pre-mRNA. Pre-mRNA is immature mRNA containing introns and exons.

Which is a mature mRNA molecule derived from the pre-mRNA by splicing?

[Source: © International Baccalaureate Organization 2019]

Explain how a single base substitution mutation in DNA can cause a change to a protein.

Explain how a single base substitution mutation in DNA can cause a change to a protein.

The diagram illustrates some of the processes involved in DNA replication.

[Source: Rohrmann, G., 2019. AcMNPV DNA replication. [diagram online] Available at:
https://www.ncbi.nlm.nih.gov/books/NBK543453/figure/ch05.F1/ [Accessed 26 October 2021].]

What is shown in the diagram?

A.  DNA polymerase bonding nucleotides in a 3’ to 5’ direction

B.  Single-stranded DNA-binding proteins on the old strands

C.  Gyrase reforming the double helix

D.  DNA ligase joining Okazaki fragments in the leading strand

All of the leaves in the image are from Solanum, a wild genus of tomato.

[Source: Courtesy: National Science Foundation, Credit Leonie Moyle.]

State one cause of variation in a plant such as the tomato.

Explain how genetic variation between the individuals in a species can be generated.

Outline how mutation can lead to cancer.

Explain the role of mutations in evolution.

Explain the effects that the environment can have on DNA in living organisms.

Outline how mutation can lead to cancer.

Explain the role of mutations in evolution.

All of the leaves in the image are from Solanum, a wild genus of tomato.

[Source: Courtesy: National Science Foundation, Credit Leonie Moyle.]

State one cause of variation in a plant such as the tomato.

All of the leaves in the image are from Solanum, a wild genus of tomato.

[Source: Courtesy: National Science Foundation, Credit Leonie Moyle.]

State one cause of variation in a plant such as the tomato.

Explain how genetic variation between the individuals in a species can be generated.

Explain how genetic variation between the individuals in a species can be generated.

Outline how mutation can lead to cancer.

Explain the role of mutations in evolution.

Outline how mutation can lead to cancer.

Explain the role of mutations in evolution.

Explain the effects that the environment can have on DNA in living organisms.

Explain the effects that the environment can have on DNA in living organisms.

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

State the role of cyclins in the cell cycle.

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.

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

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.

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

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.

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

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

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]

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.

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]

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

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.

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

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

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

Advantage:

Disadvantage:

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.

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

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

At which stage of meiosis are bivalents formed?

A. Interphase

B. Prophase I

C. Prophase II

D. Metaphase II

In which stage of the cell cycle are chromosomes duplicated?

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

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

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

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 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.

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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

State the role of cyclins in the cell cycle.

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.

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

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.

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.

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.

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 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]

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.

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]

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

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.

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

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

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

Advantage:

Disadvantage:

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

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

Advantage:

Disadvantage:

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.

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

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

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.

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

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

At which stage of meiosis are bivalents formed?

A. Interphase

B. Prophase I

C. Prophase II

D. Metaphase II

In which stage of the cell cycle are chromosomes duplicated?

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

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

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

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.

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 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

Insulin is produced in β cells of the pancreas and not in other cells of the human body. Explain how differentiation of cells and regulation of gene expression allow proteins such as insulin to be produced in only certain types of body cell.

What is the difference between the DNA of adult identical (monozygotic) twins?

A. Order of genes

B. Sequence of nucleotides

C. Methylation pattern

D. Ratio of complementary base pairs

The micrograph of a section through a plant stem shows at least ten different types of cells.

[Source: Joan Carles Juarez / Shutterstock.com.]

What explains the differences between these cells?

A. Only one gene is expressed in each cell type.

B. Different genes are expressed in each cell type.

C. Only useful genes remain in the DNA of each cell type.

D. Changes in the DNA sequence take place when these cells develop.

Which statement correctly describes genome and proteome?

A. Only the genome but not the proteome can be analysed using gel electrophoresis.

B. The genome and the proteome are the same in all tissues in an organism.

C. In cells of different tissues, the genome is the same while the proteome varies.

D. Only mutations in the proteome but not in the genome cause any variability.

Outline how nucleosomes affect the transcription of DNA.

State one reason that identical twins may show different methylation patterns as they grow older.

The graph shows the effect of methylation on the expression of MT1E, a gene involved in the control of prostate cancer development. Patients with a reduced expression of this gene are more likely to develop prostate cancer.

_{[Source: © 2017 Demidenko et al. 2017. Decreased expression of MT1E is a potential biomarker of
prostate cancer progression. Oncotarget, 8, pp. 61709–61718. Distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0). Image redrawn and reannotated.]}

What are effects of MT1E methylation?

A.  It reduces transcription of MT1E, increasing the risk of prostate cancer.

B.  It increases translation of MT1E, reducing the risk of prostate cancer.

C.  It reduces replication of MT1E, reducing the risk of prostate cancer.

D.  It increases the chances of mutation in proto-oncogenes, increasing the risk of prostate cancer.

DNA methylation profiles in zebrafish (Danio rerio) gametes were determined. The methylated areas were divided into three groups according to the amount of methylation: high, medium and low methylation.

^{[Source: Potok, M.E., Nix, D.A., Parnell, T.J. and Cairns, B.R., 2013.
Reprogramming the Maternal Zebrafish Genome afterFertilization to
Match the Paternal Methylation Pattern.
Cell, [e-journal] 153(4), pp. 759–772. http://dx.doi.org/10.1016/j.
cell.2013.04.030.]}

Methylation of DNA in sperm and egg is removed immediately after fertilization. What is the reason for this?

A.  Methylation allows RNA polymerase to join the promoter.

B.  It is needed to form homologous pairs of chromosomes.

C.  It allows expression of genes linked to early development.

D.  Transcription of promoters only occurs in methylated genes.

The graph shows the effect of methylation on the expression of MT1E, a gene involved in the control of prostate cancer development. Patients with a reduced expression of this gene are more likely to develop prostate cancer.

_{[Source: © 2017 Demidenko et al. 2017. Decreased expression of MT1E is a potential biomarker of
prostate cancer progression. Oncotarget, 8, pp. 61709–61718. Distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0). Image redrawn and reannotated.]}

What are effects of MT1E methylation?

A.  It reduces transcription of MT1E, increasing the risk of prostate cancer.

B.  It increases translation of MT1E, reducing the risk of prostate cancer.

C.  It reduces replication of MT1E, reducing the risk of prostate cancer.

D.  It increases the chances of mutation in proto-oncogenes, increasing the risk of prostate cancer.

The graph shows the effect of methylation on the expression of MT1E, a gene involved in the control of prostate cancer development. Patients with a reduced expression of this gene are more likely to develop prostate cancer.

_{[Source: © 2017 Demidenko et al. 2017. Decreased expression of MT1E is a potential biomarker of
prostate cancer progression. Oncotarget, 8, pp. 61709–61718. Distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0). Image redrawn and reannotated.]}

What are effects of MT1E methylation?

A.  It reduces transcription of MT1E, increasing the risk of prostate cancer.

B.  It increases translation of MT1E, reducing the risk of prostate cancer.

C.  It reduces replication of MT1E, reducing the risk of prostate cancer.

D.  It increases the chances of mutation in proto-oncogenes, increasing the risk of prostate cancer.

Insulin is produced in β cells of the pancreas and not in other cells of the human body. Explain how differentiation of cells and regulation of gene expression allow proteins such as insulin to be produced in only certain types of body cell.

Insulin is produced in β cells of the pancreas and not in other cells of the human body. Explain how differentiation of cells and regulation of gene expression allow proteins such as insulin to be produced in only certain types of body cell.

What is the difference between the DNA of adult identical (monozygotic) twins?

A. Order of genes

B. Sequence of nucleotides

C. Methylation pattern

D. Ratio of complementary base pairs

The micrograph of a section through a plant stem shows at least ten different types of cells.

[Source: Joan Carles Juarez / Shutterstock.com.]

What explains the differences between these cells?

A. Only one gene is expressed in each cell type.

B. Different genes are expressed in each cell type.

C. Only useful genes remain in the DNA of each cell type.

D. Changes in the DNA sequence take place when these cells develop.

Which statement correctly describes genome and proteome?

A. Only the genome but not the proteome can be analysed using gel electrophoresis.

B. The genome and the proteome are the same in all tissues in an organism.

C. In cells of different tissues, the genome is the same while the proteome varies.

D. Only mutations in the proteome but not in the genome cause any variability.

Outline how nucleosomes affect the transcription of DNA.

State one reason that identical twins may show different methylation patterns as they grow older.

Outline how nucleosomes affect the transcription of DNA.

State one reason that identical twins may show different methylation patterns as they grow older.

The graph shows the effect of methylation on the expression of MT1E, a gene involved in the control of prostate cancer development. Patients with a reduced expression of this gene are more likely to develop prostate cancer.

_{[Source: © 2017 Demidenko et al. 2017. Decreased expression of MT1E is a potential biomarker of
prostate cancer progression. Oncotarget, 8, pp. 61709–61718. Distributed under the terms of the Creative Commons Attribution License 3.0 (CC BY 3.0). Image redrawn and reannotated.]}

What are effects of MT1E methylation?

A.  It reduces transcription of MT1E, increasing the risk of prostate cancer.

B.  It increases translation of MT1E, reducing the risk of prostate cancer.

C.  It reduces replication of MT1E, reducing the risk of prostate cancer.

D.  It increases the chances of mutation in proto-oncogenes, increasing the risk of prostate cancer.

DNA methylation profiles in zebrafish (Danio rerio) gametes were determined. The methylated areas were divided into three groups according to the amount of methylation: high, medium and low methylation.

^{[Source: Potok, M.E., Nix, D.A., Parnell, T.J. and Cairns, B.R., 2013.
Reprogramming the Maternal Zebrafish Genome afterFertilization to
Match the Paternal Methylation Pattern.
Cell, [e-journal] 153(4), pp. 759–772. http://dx.doi.org/10.1016/j.
cell.2013.04.030.]}

Methylation of DNA in sperm and egg is removed immediately after fertilization. What is the reason for this?

A.  Methylation allows RNA polymerase to join the promoter.

B.  It is needed to form homologous pairs of chromosomes.

C.  It allows expression of genes linked to early development.

D.  Transcription of promoters only occurs in methylated genes.

The image shows human red blood cells.

[Source: someoneice/123rf.com.]

Outline what will happen to human red blood cells if transferred to distilled water.

Red blood cells from a small mammal were immersed in NaCl (sodium chloride) solutions of different concentrations for 2 hours. The graph shows the percentage of hemolysed (ruptured) red blood cells at each concentration.

Describe transport across cell membranes by osmosis.

Using the graph, estimate isotonic sucrose solutions for potato tissue and carrot tissue.

Potato:

Carrot:

Which process(es) occur(s) by osmosis?

I. Uptake of water by cells in the wall of the intestine

II. Loss of water from a plant cell in a hypertonic environment

III. Evaporation of water from sweat on the skin surface

A. I only

B. I and II only

C. II and III only

D. I, II and III

In an experiment on osmosis, red blood cells were immersed in a salt solution for two hours. The micrographs show the appearance of these cells before and after immersion in the salt solution.

Onion (Allium cepa) epidermis was placed in pure water and observed with a light microscope using high magnification.

What would happen to these cells if they were transferred to a hypertonic solution?

A.  Cells would gain mass.

B.  Cells would take in water by osmosis and swell.

C.  Cells would burst open, releasing their content.

D.  Cell membranes would detach from walls at some points.

Onion (Allium cepa) epidermis was placed in pure water and observed with a light microscope using high magnification.

What would happen to these cells if they were transferred to a hypertonic solution?

A.  Cells would gain mass.

B.  Cells would take in water by osmosis and swell.

C.  Cells would burst open, releasing their content.

D.  Cell membranes would detach from walls at some points.

The image shows human red blood cells.

[Source: someoneice/123rf.com.]

Outline what will happen to human red blood cells if transferred to distilled water.

The image shows human red blood cells.

[Source: someoneice/123rf.com.]

Outline what will happen to human red blood cells if transferred to distilled water.

Red blood cells from a small mammal were immersed in NaCl (sodium chloride) solutions of different concentrations for 2 hours. The graph shows the percentage of hemolysed (ruptured) red blood cells at each concentration.

Describe transport across cell membranes by osmosis.

Describe transport across cell membranes by osmosis.

Using the graph, estimate isotonic sucrose solutions for potato tissue and carrot tissue.

Potato:

Carrot:

Which process(es) occur(s) by osmosis?

I. Uptake of water by cells in the wall of the intestine

II. Loss of water from a plant cell in a hypertonic environment

III. Evaporation of water from sweat on the skin surface

A. I only

B. I and II only

C. II and III only

D. I, II and III

In an experiment on osmosis, red blood cells were immersed in a salt solution for two hours. The micrographs show the appearance of these cells before and after immersion in the salt solution.

Onion (Allium cepa) epidermis was placed in pure water and observed with a light microscope using high magnification.

What would happen to these cells if they were transferred to a hypertonic solution?

A.  Cells would gain mass.

B.  Cells would take in water by osmosis and swell.

C.  Cells would burst open, releasing their content.

D.  Cell membranes would detach from walls at some points.

Onion (Allium cepa) epidermis was placed in pure water and observed with a light microscope using high magnification.

What would happen to these cells if they were transferred to a hypertonic solution?

A.  Cells would gain mass.

B.  Cells would take in water by osmosis and swell.

C.  Cells would burst open, releasing their content.

D.  Cell membranes would detach from walls at some points.

Outline how sperm are produced from diploid cells in the testis and how this production can be sustained over many decades of adult life.

Explain the mechanism that prevents polyspermy during fertilization.

The graph shows the blood levels of hormones associated with the menstrual cycle.

The diagram shows the human male reproductive system.

[Source: logika600/Shutterstock]

Which numbers indicate a gland providing fluid for sperm and a tube that transports sperm only?

The diagram shows the human female reproductive system.

[Source: © International Baccalaureate Organization 2019]

What is produced by structure X?

A. FSH

B. X chromosomes

C. Fertilized eggs

D. Estrogen and progesterone

Draw a half-view of an animal-pollinated flower.

State one use of monoclonal antibodies.

The pregnancy test for humans is based on detection of the hormone HCG. What is the reason for detection of this hormone indicating pregnancy?

A. HCG is involved in milk production.

B. HCG production is blocked by negative feedback during menstruation.

C. HCG is produced by an embryo.

D. HCG is released during the acrosome reaction.

Describe the genetic and hormonal control of male sexual characteristics in a human.

What function is maintained as a result of the release of HCG?

A. Production of milk by the mammary glands

B. Release of oxytocin by the posterior pituitary gland

C. Production of FSH by the anterior pituitary gland

D. Production of progesterone by the ovary

What is a function of luteinizing hormone (LH) in the female menstrual cycle?

A. To promote secondary sexual characteristics

B. To inhibit progesterone secretion

C. To stimulate the follicle to release estrogen

D. To trigger ovulation

The image shows a cross-section of a flower.

[Source: © International Baccalaureate Organization 2019]

Where does production of haploid gametes occur?

A. I and II only

B. III and IV only

C. I and III only

D. II and IV only

The diagram shows the human female reproductive system

[Source: © International Baccalaureate Organization 2019]

Which labels indicate where fertilization occurs and where luteinizing hormone (LH) acts?

Describe the hormone feedback mechanisms that help to prepare a woman’s body for pregnancy, sustain the pregnancy and then give birth.

State the name and function of structures I and II.

Structure I name and function: ..............................................................................................................

..........................................................................................................................................................

Structure II name and function: .............................................................................................................

..........................................................................................................................................................

Structure III is the ovary. Outline the processes that occur in the ovary.

Pangolins are unique among mammals in having evolved scales, which are a recognition feature of reptiles. Explain which features you expect pangolins to have, which would show that they are mammals, not reptiles.

Outline how sperm are produced from diploid cells in the testis and how this production can be sustained over many decades of adult life.

Outline how sperm are produced from diploid cells in the testis and how this production can be sustained over many decades of adult life.

Explain the mechanism that prevents polyspermy during fertilization.

Explain the mechanism that prevents polyspermy during fertilization.

The graph shows the blood levels of hormones associated with the menstrual cycle.

The diagram shows the human male reproductive system.

[Source: logika600/Shutterstock]

Which numbers indicate a gland providing fluid for sperm and a tube that transports sperm only?

The diagram shows the human female reproductive system.

[Source: © International Baccalaureate Organization 2019]

What is produced by structure X?

A. FSH

B. X chromosomes

C. Fertilized eggs

D. Estrogen and progesterone

Draw a half-view of an animal-pollinated flower.

State one use of monoclonal antibodies.

State one use of monoclonal antibodies.

The pregnancy test for humans is based on detection of the hormone HCG. What is the reason for detection of this hormone indicating pregnancy?

A. HCG is involved in milk production.

B. HCG production is blocked by negative feedback during menstruation.

C. HCG is produced by an embryo.

D. HCG is released during the acrosome reaction.

Describe the genetic and hormonal control of male sexual characteristics in a human.

Describe the genetic and hormonal control of male sexual characteristics in a human.

What function is maintained as a result of the release of HCG?

A. Production of milk by the mammary glands

B. Release of oxytocin by the posterior pituitary gland

C. Production of FSH by the anterior pituitary gland

D. Production of progesterone by the ovary

What is a function of luteinizing hormone (LH) in the female menstrual cycle?

A. To promote secondary sexual characteristics

B. To inhibit progesterone secretion

C. To stimulate the follicle to release estrogen

D. To trigger ovulation

The image shows a cross-section of a flower.

[Source: © International Baccalaureate Organization 2019]

Where does production of haploid gametes occur?

A. I and II only

B. III and IV only

C. I and III only

D. II and IV only

The diagram shows the human female reproductive system

[Source: © International Baccalaureate Organization 2019]

Which labels indicate where fertilization occurs and where luteinizing hormone (LH) acts?

Describe the hormone feedback mechanisms that help to prepare a woman’s body for pregnancy, sustain the pregnancy and then give birth.

Describe the hormone feedback mechanisms that help to prepare a woman’s body for pregnancy, sustain the pregnancy and then give birth.

State the name and function of structures I and II.

Structure I name and function: ..............................................................................................................

..........................................................................................................................................................

Structure II name and function: .............................................................................................................

..........................................................................................................................................................

Structure III is the ovary. Outline the processes that occur in the ovary.

State the name and function of structures I and II.

Structure I name and function: ..............................................................................................................

..........................................................................................................................................................

Structure II name and function: .............................................................................................................

..........................................................................................................................................................

Structure III is the ovary. Outline the processes that occur in the ovary.

Pangolins are unique among mammals in having evolved scales, which are a recognition feature of reptiles. Explain which features you expect pangolins to have, which would show that they are mammals, not reptiles.

Pangolins are unique among mammals in having evolved scales, which are a recognition feature of reptiles. Explain which features you expect pangolins to have, which would show that they are mammals, not reptiles.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

The pedigree chart shows a family affected by cystic fibrosis.

[Source: © International Baccalaureate Organization 2019]

What is the genotype of the affected boy’s father?

A. AA only

B. Either AA or Aa

C. Aa only

D. aa only

Autosomal genes are located in chromosomes that are not sex chromosomes. The inheritance of autosomal genes is affected by whether the genes are linked or unlinked. Explain the two types of inheritance, using the example of parents that are heterozygous for two genes A and B.

Draw a Punnett square to show all the possible genotypes of Queen Victoria’s children.

Explain gene linkage and its effects on inheritance.

Which pedigree chart is consistent with the inheritance of red-green colour blindness?

[Source: © International Baccalaureate Organization 2019]

William Bateson and Reginald Punnett used the sweet pea (Lathyrus odoratus) in genetics studies in the early 20^th century. Pure-breeding plants that produced purple flowers and long pollen grains were crossed with pure-breeding plants that produced red flowers and round pollen grains. The resulting offspring all produced purple flowers and long pollen grains. Two of the F₁ generation plants were crossed. The table shows the ratio of phenotypes in the F₂ generation. 

What is an explanation for these experimental results?

A. Purple flowers and long pollen grains are dominant and the alleles have assorted independently.

B. The genes for flower colour and pollen shape are linked and all plants producing long pollen grains are recombinants.

C. The genes for flower colour and pollen shape are linked and all plants producing red flowers are recombinants.

D. Plants producing purple flowers and round pollen grains arose through crossing over.

A pair of alleles controls the secretion of antigens corresponding to blood group in saliva. Examine the pedigree chart.

[Source: © International Baccalaureate Organization 2019]

Based on this pedigree chart, which best describes the allele conferring antigen secretion in saliva?

A. Dominant

B. Recessive

C. Sex-linked

D. Co-dominant

Explain the reasons for variation in human height.

Congenital lactase deficiency is a type of lactose intolerance that occurs in infants. It is inherited in an autosomal recessive pattern. Calculate the chance of congenital lactose intolerance in a child whose parents are both carriers for the disorder, showing fully how you reached your answer.

A family has a history of hemophilia that is caused by a sex-linked recessive allele. A woman from this family is a carrier and marries a man who does not have the allele. Showing your working, determine the probability of their children having the disease.

Creeper in chickens is a condition in which the chickens are born with very short legs. The creeper allele (C) is dominant over the normal allele (c). Embryos which are homozygous for the dominant allele fail to develop into viable chickens and die before they hatch. What phenotypic ratio would you expect in the live offspring of a cross between two creeper chickens?

A. All creeper

B. 1 creeper; 2 normal

C. 2 creeper; 1 normal

D. 3 creeper; 1 normal

The pedigree chart shows the inheritance of hemophilia in some of the descendants of Queen Victoria. Which letter points to a family member certain to be heterozygous?

[Source: © International Baccalaureate Organization 2019]

In fruit flies (Drosophila melanogaster), grey bodies (b⁺) are dominant to black bodies (b) and normal wings (vg⁺) are dominant to vestigial wings (vg). Homozygous vestigial winged, black bodied flies were crossed with individuals that were heterozygous for both traits. 2300 individuals were counted and the phenotypes observed were recorded as shown.

965 normal wings, grey bodies
944 vestigial wings, black bodies
206 vestigial wings, grey bodies
185 normal wings, black bodies

Which statement is valid?

A. The predicted phenotypic ratio was 9:3:3: 1.

B. There is independent assortment of wings but not body colour.

C. The expected number of vestigial winged, grey bodied flies was 575.

D. The traits are on different chromosomes.

Outline the inheritance of blood types in the ABO blood system in humans.

The system of sex determination in chimpanzees (Pan troglodytes) is the same as in other mammals. A chimpanzee has 48 chromosomes in the nuclei of its body cells.

What can be deduced from this information?

A. The sex of the chimpanzee

B. The number of genes in each chromosome

C. Whether non-disjunction has occurred

D. The number of autosomes in a diploid cell

Draw the symbol for individual X on the diagram.

Calculate the probability of male Y having an allele for the disorder.

A couple have four children whose blood groups are A, B and AB. What is the likely combination of the parents’ genotypes?

A.  I^Ai and I^Bi

B.  I^Ai and I^BI^B

C.  I^AI^B and ii

D.  I^AI^A and I^BI^B

Explain whether these results fit the predicted Mendelian ratios for this cross.

Outline one example of a human disease caused by an autosomal recessive allele.

Deduce reasons for the difference between the results of Cross 2 and Cross 3.

Identify, using one recognition feature visible in the photo, the phylum in which D. plantarius is classified.

Deduce reasons for the difference between the results of Cross 2 and Cross 3.

Explain how the presence of a Y chromosome in the cells of a human embryo causes it to develop as a male.

Using a Punnett grid, explain the results of this cross.

Suggest a reason for the F₂ generation not corresponding exactly to the expected ratio of purple-flowered and white-flowered plants.

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

A total of 271 164 people were tested for blood groups in Mexico. The pie chart summarizes the ABO blood group distribution.

^{[Source: Canizalez-Román, A. et al., 2018. Blood Groups Distribution and Gene Diversity
of the ABO and Rh (D) Loci in the Mexican Population.
BioMed Research International, (Article ID 1925619).
http://dx.doi.org/10.1155/2018/1925619. Public domain.]}

What can be concluded from the ABO blood group distribution in Mexico?

A.  Allele frequencies are not the same for all blood group alleles.

B.  The majority of the Mexican population shows a co-dominant phenotype.

C.  Most of the Mexican population can receive blood from all blood groups.

D.  Only 2 % of the Mexican population have a heterozygous genotype for blood groups.

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

Explain whether these results fit the predicted Mendelian ratios for this cross.

Outline one example of a human disease caused by an autosomal recessive allele.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

Explain the reasons for none of the females in the pedigree chart having hemophilia.

The pedigree chart shows a family affected by cystic fibrosis.

[Source: © International Baccalaureate Organization 2019]

What is the genotype of the affected boy’s father?

A. AA only

B. Either AA or Aa

C. Aa only

D. aa only

Autosomal genes are located in chromosomes that are not sex chromosomes. The inheritance of autosomal genes is affected by whether the genes are linked or unlinked. Explain the two types of inheritance, using the example of parents that are heterozygous for two genes A and B.

Autosomal genes are located in chromosomes that are not sex chromosomes. The inheritance of autosomal genes is affected by whether the genes are linked or unlinked. Explain the two types of inheritance, using the example of parents that are heterozygous for two genes A and B.

Draw a Punnett square to show all the possible genotypes of Queen Victoria’s children.

Explain gene linkage and its effects on inheritance.

Draw a Punnett square to show all the possible genotypes of Queen Victoria’s children.

Explain gene linkage and its effects on inheritance.

Which pedigree chart is consistent with the inheritance of red-green colour blindness?

[Source: © International Baccalaureate Organization 2019]

William Bateson and Reginald Punnett used the sweet pea (Lathyrus odoratus) in genetics studies in the early 20^th century. Pure-breeding plants that produced purple flowers and long pollen grains were crossed with pure-breeding plants that produced red flowers and round pollen grains. The resulting offspring all produced purple flowers and long pollen grains. Two of the F₁ generation plants were crossed. The table shows the ratio of phenotypes in the F₂ generation. 

What is an explanation for these experimental results?

A. Purple flowers and long pollen grains are dominant and the alleles have assorted independently.

B. The genes for flower colour and pollen shape are linked and all plants producing long pollen grains are recombinants.

C. The genes for flower colour and pollen shape are linked and all plants producing red flowers are recombinants.

D. Plants producing purple flowers and round pollen grains arose through crossing over.

A pair of alleles controls the secretion of antigens corresponding to blood group in saliva. Examine the pedigree chart.

[Source: © International Baccalaureate Organization 2019]

Based on this pedigree chart, which best describes the allele conferring antigen secretion in saliva?

A. Dominant

B. Recessive

C. Sex-linked

D. Co-dominant

Explain the reasons for variation in human height.

Explain the reasons for variation in human height.

Congenital lactase deficiency is a type of lactose intolerance that occurs in infants. It is inherited in an autosomal recessive pattern. Calculate the chance of congenital lactose intolerance in a child whose parents are both carriers for the disorder, showing fully how you reached your answer.

Congenital lactase deficiency is a type of lactose intolerance that occurs in infants. It is inherited in an autosomal recessive pattern. Calculate the chance of congenital lactose intolerance in a child whose parents are both carriers for the disorder, showing fully how you reached your answer.

A family has a history of hemophilia that is caused by a sex-linked recessive allele. A woman from this family is a carrier and marries a man who does not have the allele. Showing your working, determine the probability of their children having the disease.

A family has a history of hemophilia that is caused by a sex-linked recessive allele. A woman from this family is a carrier and marries a man who does not have the allele. Showing your working, determine the probability of their children having the disease.

Creeper in chickens is a condition in which the chickens are born with very short legs. The creeper allele (C) is dominant over the normal allele (c). Embryos which are homozygous for the dominant allele fail to develop into viable chickens and die before they hatch. What phenotypic ratio would you expect in the live offspring of a cross between two creeper chickens?

A. All creeper

B. 1 creeper; 2 normal

C. 2 creeper; 1 normal

D. 3 creeper; 1 normal

The pedigree chart shows the inheritance of hemophilia in some of the descendants of Queen Victoria. Which letter points to a family member certain to be heterozygous?

[Source: © International Baccalaureate Organization 2019]

In fruit flies (Drosophila melanogaster), grey bodies (b⁺) are dominant to black bodies (b) and normal wings (vg⁺) are dominant to vestigial wings (vg). Homozygous vestigial winged, black bodied flies were crossed with individuals that were heterozygous for both traits. 2300 individuals were counted and the phenotypes observed were recorded as shown.

965 normal wings, grey bodies
944 vestigial wings, black bodies
206 vestigial wings, grey bodies
185 normal wings, black bodies

Which statement is valid?

A. The predicted phenotypic ratio was 9:3:3: 1.

B. There is independent assortment of wings but not body colour.

C. The expected number of vestigial winged, grey bodied flies was 575.

D. The traits are on different chromosomes.

Outline the inheritance of blood types in the ABO blood system in humans.

Outline the inheritance of blood types in the ABO blood system in humans.

The system of sex determination in chimpanzees (Pan troglodytes) is the same as in other mammals. A chimpanzee has 48 chromosomes in the nuclei of its body cells.

What can be deduced from this information?

A. The sex of the chimpanzee

B. The number of genes in each chromosome

C. Whether non-disjunction has occurred

D. The number of autosomes in a diploid cell

Draw the symbol for individual X on the diagram.

Calculate the probability of male Y having an allele for the disorder.

Draw the symbol for individual X on the diagram.

Calculate the probability of male Y having an allele for the disorder.

A couple have four children whose blood groups are A, B and AB. What is the likely combination of the parents’ genotypes?

A.  I^Ai and I^Bi

B.  I^Ai and I^BI^B

C.  I^AI^B and ii

D.  I^AI^A and I^BI^B

Explain whether these results fit the predicted Mendelian ratios for this cross.

Explain whether these results fit the predicted Mendelian ratios for this cross.

Outline one example of a human disease caused by an autosomal recessive allele.

Outline one example of a human disease caused by an autosomal recessive allele.

Deduce reasons for the difference between the results of Cross 2 and Cross 3.

Identify, using one recognition feature visible in the photo, the phylum in which D. plantarius is classified.

Deduce reasons for the difference between the results of Cross 2 and Cross 3.

Identify, using one recognition feature visible in the photo, the phylum in which D. plantarius is classified.

Deduce reasons for the difference between the results of Cross 2 and Cross 3.

Deduce reasons for the difference between the results of Cross 2 and Cross 3.

Explain how the presence of a Y chromosome in the cells of a human embryo causes it to develop as a male.

Explain how the presence of a Y chromosome in the cells of a human embryo causes it to develop as a male.

Using a Punnett grid, explain the results of this cross.

Suggest a reason for the F₂ generation not corresponding exactly to the expected ratio of purple-flowered and white-flowered plants.

Using a Punnett grid, explain the results of this cross.

Suggest a reason for the F₂ generation not corresponding exactly to the expected ratio of purple-flowered and white-flowered plants.

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

A total of 271 164 people were tested for blood groups in Mexico. The pie chart summarizes the ABO blood group distribution.

^{[Source: Canizalez-Román, A. et al., 2018. Blood Groups Distribution and Gene Diversity
of the ABO and Rh (D) Loci in the Mexican Population.
BioMed Research International, (Article ID 1925619).
http://dx.doi.org/10.1155/2018/1925619. Public domain.]}

What can be concluded from the ABO blood group distribution in Mexico?

A.  Allele frequencies are not the same for all blood group alleles.

B.  The majority of the Mexican population shows a co-dominant phenotype.

C.  Most of the Mexican population can receive blood from all blood groups.

D.  Only 2 % of the Mexican population have a heterozygous genotype for blood groups.

Scientists sequenced the genes in each chromosome of chimpanzees (Pan troglodytes) and humans (Homo sapiens). The graph shows the mean divergence between the genes of these species by chromosome.

_{[Source: Material from: Mikkelsen, T.S. et al, Initial sequence of the chimpanzee genome and 
comparison with the human genome, 2005 Nature, reproduced with permission of SNCSC.]}

What can be deduced from this data?

A.  Autosomes are more similar than Y chromosomes.

B.  There is the same number of chromosomes in humans and chimpanzees.

C.  Humans are more closely related to chimpanzees than to other species.

D.  Smaller chromosomes are more similar than larger chromosomes.

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

The pedigree chart shows the inheritance of three generations of Duane syndrome, a condition caused by a dominant allele that affects alignment of the eyes.

_{[Source: Yang, M.-M., Ho, M. et al., 2013. Pedigree of a Chinese family with Duane retraction syndrome. [diagram online]
Available at: https://www.researchgate.net/figure/Pedigree-of-a-Chinese-family-with-Duane-retraction-syndrome-
Squares-men-circles_fig1_236921765 [Accessed 5 October 2021]. Public domain.]}

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

A.  25 %

B.  50 %

C.  75 %

D.  100 %

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

State one feature of the sloth that would indicate it is a mammal.

Explain what happens in a person when they develop type I diabetes.

Compare the data for plasma insulin levels before and after the study diet.

State which cells secrete insulin.

The hypothesis made before the study was that saturated fats in the diet affected the risk of coronary artery blockage and diabetes. Using all the data in question 1, evaluate whether this hypothesis is supported by the study.

The micrograph shows a glomerulus and Bowman’s capsule, where ultrafiltration takes place in the kidney.

[Source: MICROSCAPE/SCIENCE PHOTO LIBRARY.]

What facilitates the formation of glomerular filtrate?

A. Many fenestrations in walls of capillaries in the glomerulus

B. High pressure in the Bowman’s capsule

C. ADH secreted by the pituitary gland

D. Osmosis caused by a high concentration of urea in the blood

Discuss the control of blood glucose levels and the consequences if they are not maintained.

Explain how water balance is restored in mammals when they are dehydrated.

Humans need to balance water and solute concentrations and also excrete nitrogenous wastes. Explain how the different parts of the kidney carry out these processes.

Explain the role of the kidney in osmoregulation.

Where in the nephron is most glucose reabsorbed?

[Source: National Institute of Diabetes and Digestive and Kidney Diseases, n.d. [Nephron]. [diagram online] Available at:
https://www.niddk.nih.gov/news/media-library/9164 [Accessed 23 March 2020].]

The image shows a transverse section through a collecting duct in a vertebrate kidney.

[Source: Professor Peter Takizawa, Yale University]

How is the movement of materials across the wall of the collecting duct affected by the release of ADH from the pituitary gland?

A. There is increased movement of water in the direction of arrow I.

B. There is increased movement of sodium in the direction of arrow I.

C. There is increased movement of water in the direction of arrow II.

D. There is increased movement of sodium in the direction of arrow II.

State the region of the kidney in which the loop of Henle is situated.

Explain the role of the hormone ADH in osmoregulation.

What life function is illustrated?

A.  Nutrition

B.  Homeostasis

C.  Endocytosis

D.  Response

Explain the mechanisms involved in thermoregulation in humans.

With reference to the diagram, explain how water in sweat evaporates.

Outline the role of ADH in osmoregulation.

With reference to the diagram, explain how water in sweat evaporates.

The concentration of urea in blood plasma is typically about 30 mg per 100 ml. In urine it can be as high as 1800 mg per 100 ml. Explain how this increase in concentration is achieved.

Merriam’s kangaroo rat (Dipodomys merriami) is a small mammal found in desert biomes in the southwestern USA and Mexico. What would help these kangaroo rats to conserve water in order to survive high temperatures in desert biomes?

A.  Increased sweating

B.  A long loop of Henle

C.  Decreased secretion of ADH

D.  Decreased reabsorption from the collecting duct

Explain the mechanisms involved in thermoregulation in humans.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

State one feature of the sloth that would indicate it is a mammal.

State one feature of the sloth that would indicate it is a mammal.

Explain what happens in a person when they develop type I diabetes.

Explain what happens in a person when they develop type I diabetes.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Explain the change in heart rate during the period of hibernation.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

State one feature of the sloth that would indicate it is a mammal.

State one feature of the sloth that would indicate it is a mammal.

Explain what happens in a person when they develop type I diabetes.

Explain what happens in a person when they develop type I diabetes.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

State one feature of the sloth that would indicate it is a mammal.

State one feature of the sloth that would indicate it is a mammal.

Explain what happens in a person when they develop type I diabetes.

Explain what happens in a person when they develop type I diabetes.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

State one feature of the sloth that would indicate it is a mammal.

State one feature of the sloth that would indicate it is a mammal.

Explain what happens in a person when they develop type I diabetes.

Explain what happens in a person when they develop type I diabetes.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

Explain the change in heart rate during the period of hibernation.

Describe what is happening to the bone during hibernation.

Suggest how the graph would differ for a human during a long period of inactivity.

Calculate the percentage increase in the mean concentration of osteocalcin from pre-hibernation to hibernation.

A hypothesis has been proposed that an increase in parathyroid hormone concentration causes an increase in osteocalcin in bears. Evaluate the evidence for this hypothesis provided by the data.

State one feature of the sloth that would indicate it is a mammal.

State one feature of the sloth that would indicate it is a mammal.

Explain what happens in a person when they develop type I diabetes.

Explain what happens in a person when they develop type I diabetes.

Compare the data for plasma insulin levels before and after the study diet.

State which cells secrete insulin.

The hypothesis made before the study was that saturated fats in the diet affected the risk of coronary artery blockage and diabetes. Using all the data in question 1, evaluate whether this hypothesis is supported by the study.

Compare the data for plasma insulin levels before and after the study diet.

State which cells secrete insulin.

The hypothesis made before the study was that saturated fats in the diet affected the risk of coronary artery blockage and diabetes. Using all the data in question 1, evaluate whether this hypothesis is supported by the study.

The micrograph shows a glomerulus and Bowman’s capsule, where ultrafiltration takes place in the kidney.

[Source: MICROSCAPE/SCIENCE PHOTO LIBRARY.]

What facilitates the formation of glomerular filtrate?

A. Many fenestrations in walls of capillaries in the glomerulus

B. High pressure in the Bowman’s capsule

C. ADH secreted by the pituitary gland

D. Osmosis caused by a high concentration of urea in the blood

Discuss the control of blood glucose levels and the consequences if they are not maintained.

Discuss the control of blood glucose levels and the consequences if they are not maintained.

Explain how water balance is restored in mammals when they are dehydrated.

Explain how water balance is restored in mammals when they are dehydrated.

Humans need to balance water and solute concentrations and also excrete nitrogenous wastes. Explain how the different parts of the kidney carry out these processes.

Humans need to balance water and solute concentrations and also excrete nitrogenous wastes. Explain how the different parts of the kidney carry out these processes.

Explain the role of the kidney in osmoregulation.

Explain the role of the kidney in osmoregulation.

Where in the nephron is most glucose reabsorbed?

[Source: National Institute of Diabetes and Digestive and Kidney Diseases, n.d. [Nephron]. [diagram online] Available at:
https://www.niddk.nih.gov/news/media-library/9164 [Accessed 23 March 2020].]

The image shows a transverse section through a collecting duct in a vertebrate kidney.

[Source: Professor Peter Takizawa, Yale University]

How is the movement of materials across the wall of the collecting duct affected by the release of ADH from the pituitary gland?

A. There is increased movement of water in the direction of arrow I.

B. There is increased movement of sodium in the direction of arrow I.

C. There is increased movement of water in the direction of arrow II.

D. There is increased movement of sodium in the direction of arrow II.

State the region of the kidney in which the loop of Henle is situated.

Explain the role of the hormone ADH in osmoregulation.

State the region of the kidney in which the loop of Henle is situated.

Explain the role of the hormone ADH in osmoregulation.

What life function is illustrated?

A.  Nutrition

B.  Homeostasis

C.  Endocytosis

D.  Response

Explain the mechanisms involved in thermoregulation in humans.

Explain the mechanisms involved in thermoregulation in humans.

With reference to the diagram, explain how water in sweat evaporates.

With reference to the diagram, explain how water in sweat evaporates.

Outline the role of ADH in osmoregulation.

Outline the role of ADH in osmoregulation.

With reference to the diagram, explain how water in sweat evaporates.

With reference to the diagram, explain how water in sweat evaporates.

The concentration of urea in blood plasma is typically about 30 mg per 100 ml. In urine it can be as high as 1800 mg per 100 ml. Explain how this increase in concentration is achieved.

The concentration of urea in blood plasma is typically about 30 mg per 100 ml. In urine it can be as high as 1800 mg per 100 ml. Explain how this increase in concentration is achieved.

Merriam’s kangaroo rat (Dipodomys merriami) is a small mammal found in desert biomes in the southwestern USA and Mexico. What would help these kangaroo rats to conserve water in order to survive high temperatures in desert biomes?

A.  Increased sweating

B.  A long loop of Henle

C.  Decreased secretion of ADH

D.  Decreased reabsorption from the collecting duct

The graph shows the proportion of a bacterial population of Neisseria gonorrhoeae, displaying resistance to the antibiotic tetracycline.

[Source: © All rights reserved. Canadian Antimicrobial Resistance Surveillance System Report, 2016. Public Health Agency of Canada. Adapted and reproduced with permission from the Minister of Health, 2022.]

What can be deduced from this graph?

A. Bacteria with beneficial adaptations survive and pass on their genes.

B. Immunity to tetracycline is triggered by over-use of the antibiotic.

C. Genetic variation in this bacterial population is increasing.

D. Use of tetracycline inhibits the growth of antibiotic-resistant N. gonorrhoeae.

Explain how natural selection can cause mate selection behaviour patterns to develop in a species such as eastern bluebirds.

Explain how natural selection can cause traits such as drought resistance to develop in wild plants.

By the end of the 19th century in England, the dark form of the moth Biston betularia formed up to 98$$% of the total population in industrial areas. From 1970, the percentage of dark forms decreased significantly. What is an explanation for the decrease?

A.  An increase in environmental pollution killed the dark forms more than the light forms.

B.  Reduction of pollution resulted in greater camouflage for light forms of the moth.

C.  Dark forms could no longer find mates.

D.  Light forms had superior feeding mechanisms.

Domestic dogs (Canis familiaris) have evolved from grey wolves (Canis lupus). Evidence suggests that the domestication of dogs first occurred around 30 000 years ago. Which best describes the evolution giving rise to the domestic dog?

A.  The wolf produced offspring in large numbers which underwent natural selection.

B.  Variations in the wolf population that resembled modern dogs favoured wolf survival.

C.  Wolves showing favourable traits were selected for breeding.

D.  Dogs were better suited to changes in the natural environment than wolves.

Explain how natural selection could increase the prevalence of an antibiotic resistance gene in a species of soil bacterium.

Suggest two reasons, other than mate selection, for variation in plumage colouration in red knots.

The graphs show how the frequency (f) of a trait within a population changes when subjected to selection pressures. Which graph shows stabilizing selection?

Domestic dogs (Canis familiaris) have evolved from grey wolves (Canis lupus). Evidence suggests that the domestication of dogs first occurred around 30 000 years ago. Which best describes the evolution giving rise to the domestic dog?

A.  The wolf produced offspring in large numbers which underwent natural selection.

B.  Variations in the wolf population that resembled modern dogs favoured wolf survival.

C.  Wolves showing favourable traits were selected for breeding.

D.  Dogs were better suited to changes in the natural environment than wolves.

Domestic dogs (Canis familiaris) have evolved from grey wolves (Canis lupus). Evidence suggests that the domestication of dogs first occurred around 30 000 years ago. Which best describes the evolution giving rise to the domestic dog?

A.  The wolf produced offspring in large numbers which underwent natural selection.

B.  Variations in the wolf population that resembled modern dogs favoured wolf survival.

C.  Wolves showing favourable traits were selected for breeding.

D.  Dogs were better suited to changes in the natural environment than wolves.

The graph shows the proportion of a bacterial population of Neisseria gonorrhoeae, displaying resistance to the antibiotic tetracycline.

[Source: © All rights reserved. Canadian Antimicrobial Resistance Surveillance System Report, 2016. Public Health Agency of Canada. Adapted and reproduced with permission from the Minister of Health, 2022.]

What can be deduced from this graph?

A. Bacteria with beneficial adaptations survive and pass on their genes.

B. Immunity to tetracycline is triggered by over-use of the antibiotic.

C. Genetic variation in this bacterial population is increasing.

D. Use of tetracycline inhibits the growth of antibiotic-resistant N. gonorrhoeae.

The graph shows the proportion of a bacterial population of Neisseria gonorrhoeae, displaying resistance to the antibiotic tetracycline.

[Source: © All rights reserved. Canadian Antimicrobial Resistance Surveillance System Report, 2016. Public Health Agency of Canada. Adapted and reproduced with permission from the Minister of Health, 2022.]

What can be deduced from this graph?

A. Bacteria with beneficial adaptations survive and pass on their genes.

B. Immunity to tetracycline is triggered by over-use of the antibiotic.

C. Genetic variation in this bacterial population is increasing.

D. Use of tetracycline inhibits the growth of antibiotic-resistant N. gonorrhoeae.

The graph shows the proportion of a bacterial population of Neisseria gonorrhoeae, displaying resistance to the antibiotic tetracycline.

[Source: © All rights reserved. Canadian Antimicrobial Resistance Surveillance System Report, 2016. Public Health Agency of Canada. Adapted and reproduced with permission from the Minister of Health, 2022.]

What can be deduced from this graph?

A. Bacteria with beneficial adaptations survive and pass on their genes.

B. Immunity to tetracycline is triggered by over-use of the antibiotic.

C. Genetic variation in this bacterial population is increasing.

D. Use of tetracycline inhibits the growth of antibiotic-resistant N. gonorrhoeae.

The graph shows the proportion of a bacterial population of Neisseria gonorrhoeae, displaying resistance to the antibiotic tetracycline.

[Source: © All rights reserved. Canadian Antimicrobial Resistance Surveillance System Report, 2016. Public Health Agency of Canada. Adapted and reproduced with permission from the Minister of Health, 2022.]

What can be deduced from this graph?

A. Bacteria with beneficial adaptations survive and pass on their genes.

B. Immunity to tetracycline is triggered by over-use of the antibiotic.

C. Genetic variation in this bacterial population is increasing.

D. Use of tetracycline inhibits the growth of antibiotic-resistant N. gonorrhoeae.

The graph shows the proportion of a bacterial population of Neisseria gonorrhoeae, displaying resistance to the antibiotic tetracycline.

[Source: © All rights reserved. Canadian Antimicrobial Resistance Surveillance System Report, 2016. Public Health Agency of Canada. Adapted and reproduced with permission from the Minister of Health, 2022.]

What can be deduced from this graph?

A. Bacteria with beneficial adaptations survive and pass on their genes.

B. Immunity to tetracycline is triggered by over-use of the antibiotic.

C. Genetic variation in this bacterial population is increasing.

D. Use of tetracycline inhibits the growth of antibiotic-resistant N. gonorrhoeae.

Explain how natural selection can cause mate selection behaviour patterns to develop in a species such as eastern bluebirds.

Explain how natural selection can cause traits such as drought resistance to develop in wild plants.

Explain how natural selection can cause traits such as drought resistance to develop in wild plants.

By the end of the 19th century in England, the dark form of the moth Biston betularia formed up to 98$$% of the total population in industrial areas. From 1970, the percentage of dark forms decreased significantly. What is an explanation for the decrease?

A.  An increase in environmental pollution killed the dark forms more than the light forms.

B.  Reduction of pollution resulted in greater camouflage for light forms of the moth.

C.  Dark forms could no longer find mates.

D.  Light forms had superior feeding mechanisms.

Domestic dogs (Canis familiaris) have evolved from grey wolves (Canis lupus). Evidence suggests that the domestication of dogs first occurred around 30 000 years ago. Which best describes the evolution giving rise to the domestic dog?

A.  The wolf produced offspring in large numbers which underwent natural selection.

B.  Variations in the wolf population that resembled modern dogs favoured wolf survival.

C.  Wolves showing favourable traits were selected for breeding.

D.  Dogs were better suited to changes in the natural environment than wolves.

Explain how natural selection could increase the prevalence of an antibiotic resistance gene in a species of soil bacterium.

Explain how natural selection could increase the prevalence of an antibiotic resistance gene in a species of soil bacterium.

Suggest two reasons, other than mate selection, for variation in plumage colouration in red knots.

The graphs show how the frequency (f) of a trait within a population changes when subjected to selection pressures. Which graph shows stabilizing selection?

Describe how ingested plastics can cause problems to marine birds.

Sea otters are considered keystone species in this environment. Suggest how the presence of sea otters could affect the algae population.

State the distance from the city centre at which the highest proportion of plants sampled contained HCN.

Outline the relationship shown in the graph.

Deduce whether the pattern of cyanogenesis was the same in all of the areas around all four cities.

Using all of the data so far, suggest whether exposure to freezing temperatures in the four cities is supported as a reason for the differences in HCN production in T. repens.

Describe the effect of temperature on the total biomass.

Compare and contrast the effects of temperature on the biomass of autotrophs and heterotrophs with added nutrients.

Explain the effect of temperature on the rate of photosynthesis in this mesocosm.

Suggest reasons for the decreases in biomass of autotrophs as temperature rises, despite the increases in photosynthesis.

Suggest two abiotic factors, other than temperature and nutrient supply, that may affect the production of biomass of the grasslands.

Explain the movement of energy and inorganic nutrients in an ecosystem.

Compare and contrast the design of both mesocosms (vertical flow and horizontal flow).

Describe how toxins such as DDT might concentrate in the bodies of birds.

Outline how the prickly pear cactus may become an ecological problem in Kruger National Park.

Label with a P on the $x$-axis the level of commercial sea fishing activity that would result in maximum sustainability.

State two variables measured by the probes.

1: 

2: 

Outline the requirements for sustainability within a sealed mesocosm.

Deduce, giving reasons, which brown pelican population decreased the most in the years following the study.

Outline the biomagnification of DDE in brown pelicans.

Duckweed (Lemna gibba) is a plant that grows on the surface of water. It was grown in cultures and the percentage increase in total area covered per day was obtained. The graph shows the specific growth rates per day for duckweed measured over 22 days.

^{Material from: Mkandawire, M. and Dudel, E.G., Assignment of Lemna gibba L. (duckweed) bioassay for in situ
ecotoxicity assessment, published 2005, Aquatic Ecology, reproduced with permission of SNCSC.}

Suggest reasons for the slowing down of duckweed population growth after day 6.

Suggest two reasons, other than elevation, for the differences in nitrogen concentration in leaves of pitcher plants.

Describe how toxins such as DDT might concentrate in the bodies of birds.

Describe how ingested plastics can cause problems to marine birds.

Sea otters are considered keystone species in this environment. Suggest how the presence of sea otters could affect the algae population.

State the distance from the city centre at which the highest proportion of plants sampled contained HCN.

Outline the relationship shown in the graph.

Deduce whether the pattern of cyanogenesis was the same in all of the areas around all four cities.

Using all of the data so far, suggest whether exposure to freezing temperatures in the four cities is supported as a reason for the differences in HCN production in T. repens.

State the distance from the city centre at which the highest proportion of plants sampled contained HCN.

Outline the relationship shown in the graph.

Deduce whether the pattern of cyanogenesis was the same in all of the areas around all four cities.

Using all of the data so far, suggest whether exposure to freezing temperatures in the four cities is supported as a reason for the differences in HCN production in T. repens.

Describe the effect of temperature on the total biomass.

Compare and contrast the effects of temperature on the biomass of autotrophs and heterotrophs with added nutrients.

Explain the effect of temperature on the rate of photosynthesis in this mesocosm.

Suggest reasons for the decreases in biomass of autotrophs as temperature rises, despite the increases in photosynthesis.

Suggest two abiotic factors, other than temperature and nutrient supply, that may affect the production of biomass of the grasslands.

Describe the effect of temperature on the total biomass.

Compare and contrast the effects of temperature on the biomass of autotrophs and heterotrophs with added nutrients.

Explain the effect of temperature on the rate of photosynthesis in this mesocosm.

Suggest reasons for the decreases in biomass of autotrophs as temperature rises, despite the increases in photosynthesis.

Suggest two abiotic factors, other than temperature and nutrient supply, that may affect the production of biomass of the grasslands.

Explain the movement of energy and inorganic nutrients in an ecosystem.

Compare and contrast the design of both mesocosms (vertical flow and horizontal flow).

Describe how toxins such as DDT might concentrate in the bodies of birds.

Describe how toxins such as DDT might concentrate in the bodies of birds.

Outline how the prickly pear cactus may become an ecological problem in Kruger National Park.

Label with a P on the $x$-axis the level of commercial sea fishing activity that would result in maximum sustainability.

State two variables measured by the probes.

1: 

2: 

Outline the requirements for sustainability within a sealed mesocosm.

Deduce, giving reasons, which brown pelican population decreased the most in the years following the study.

Outline the biomagnification of DDE in brown pelicans.

Duckweed (Lemna gibba) is a plant that grows on the surface of water. It was grown in cultures and the percentage increase in total area covered per day was obtained. The graph shows the specific growth rates per day for duckweed measured over 22 days.

^{Material from: Mkandawire, M. and Dudel, E.G., Assignment of Lemna gibba L. (duckweed) bioassay for in situ
ecotoxicity assessment, published 2005, Aquatic Ecology, reproduced with permission of SNCSC.}

Suggest reasons for the slowing down of duckweed population growth after day 6.

Suggest two reasons, other than elevation, for the differences in nitrogen concentration in leaves of pitcher plants.

Explain how energy enters, flows through and is lost from marine food chains.

Calculate the increase in mean global temperature between 1880 and 2010.

.......... °C

Explain how increased carbon dioxide in the air leads to the greenhouse effect.

Describe the evidence that is provided by the data in the table for the harmful effects of rising sea temperatures on corals.

The researchers concluded that there was a threshold coral cover percentage, below which infection rates tended to remain fairly low. Using the data in the table, identify this threshold level.

Suggest a reason for a larger percentage of corals being infected with white syndrome on reefs with a higher cover of corals.

Compare and contrast the data for 1998–1999 and 2002–2003.

Some scientists predict that, if humans continue to produce carbon dioxide at the current rate, the pH of the oceans will become more acidic. Suggest possible effects on the coral reefs.

Which gases have made the most significant contributions to global warming?

A. Water and carbon dioxide

B. Carbon dioxide and methane

C. Methane and nitrous oxide

D. Carbon dioxide and ozone

Discuss the relationship between atmospheric carbon dioxide concentration and global temperatures.

The map shows the widespread distribution of coral reef ecosystems (indicated by black dots) in the world’s oceans. Death of coral reefs is related to increasing atmospheric carbon dioxide concentrations.

[Source: National Oceanic and Atmospheric Administration, 2021. Where Reef Building Corals Found. [map online] Available at: https://oceanservice.noaa.gov/education/tutorial_corals/media/supp_coral05a.html [Accessed 20 May 2021].]

Explain how increased atmospheric carbon dioxide concentrations can lead to coral death.

It has been argued that variation in the global mean surface temperature has been caused by variation in energy from the Sun. Analyse whether evidence from the graphs supports this argument.

Explain how increased levels of atmospheric carbon dioxide contribute to global warming.

Suggest reasons for the differences in LAI between the boreal and equatorial zones.

Analyse the data shown in the graph for evidence of a relationship between LAI and El Niño events.

State the trend.

Global ecosystem modelling suggests that most of the change in LAI is due to increases in atmospheric carbon dioxide. Explain how rising atmospheric carbon dioxide (CO₂) concentration could cause the observed change in LAI.

State the effect of elevated CO₂ on net primary production in these young, developing forests.

Outline one benefit of conducting similar FACE experiments in multiple locations.

Evaluate the evidence from the bar chart that increases in carbon dioxide cause increases in carbon storage in young, developing forests.

Describe how human activities have caused average surface air temperatures on Earth to increase.

Explain how energy enters, flows through and is lost from marine food chains.

Explain how energy enters, flows through and is lost from marine food chains.

Calculate the increase in mean global temperature between 1880 and 2010.

.......... °C

Explain how increased carbon dioxide in the air leads to the greenhouse effect.

Calculate the increase in mean global temperature between 1880 and 2010.

.......... °C

Explain how increased carbon dioxide in the air leads to the greenhouse effect.

Describe the evidence that is provided by the data in the table for the harmful effects of rising sea temperatures on corals.

The researchers concluded that there was a threshold coral cover percentage, below which infection rates tended to remain fairly low. Using the data in the table, identify this threshold level.

Suggest a reason for a larger percentage of corals being infected with white syndrome on reefs with a higher cover of corals.

Compare and contrast the data for 1998–1999 and 2002–2003.

Some scientists predict that, if humans continue to produce carbon dioxide at the current rate, the pH of the oceans will become more acidic. Suggest possible effects on the coral reefs.

Describe the evidence that is provided by the data in the table for the harmful effects of rising sea temperatures on corals.

The researchers concluded that there was a threshold coral cover percentage, below which infection rates tended to remain fairly low. Using the data in the table, identify this threshold level.

Suggest a reason for a larger percentage of corals being infected with white syndrome on reefs with a higher cover of corals.

Compare and contrast the data for 1998–1999 and 2002–2003.

Some scientists predict that, if humans continue to produce carbon dioxide at the current rate, the pH of the oceans will become more acidic. Suggest possible effects on the coral reefs.

Which gases have made the most significant contributions to global warming?

A. Water and carbon dioxide

B. Carbon dioxide and methane

C. Methane and nitrous oxide

D. Carbon dioxide and ozone

Discuss the relationship between atmospheric carbon dioxide concentration and global temperatures.

Discuss the relationship between atmospheric carbon dioxide concentration and global temperatures.

The map shows the widespread distribution of coral reef ecosystems (indicated by black dots) in the world’s oceans. Death of coral reefs is related to increasing atmospheric carbon dioxide concentrations.

[Source: National Oceanic and Atmospheric Administration, 2021. Where Reef Building Corals Found. [map online] Available at: https://oceanservice.noaa.gov/education/tutorial_corals/media/supp_coral05a.html [Accessed 20 May 2021].]

Explain how increased atmospheric carbon dioxide concentrations can lead to coral death.

The map shows the widespread distribution of coral reef ecosystems (indicated by black dots) in the world’s oceans. Death of coral reefs is related to increasing atmospheric carbon dioxide concentrations.

[Source: National Oceanic and Atmospheric Administration, 2021. Where Reef Building Corals Found. [map online] Available at: https://oceanservice.noaa.gov/education/tutorial_corals/media/supp_coral05a.html [Accessed 20 May 2021].]

Explain how increased atmospheric carbon dioxide concentrations can lead to coral death.

It has been argued that variation in the global mean surface temperature has been caused by variation in energy from the Sun. Analyse whether evidence from the graphs supports this argument.

Explain how increased levels of atmospheric carbon dioxide contribute to global warming.

It has been argued that variation in the global mean surface temperature has been caused by variation in energy from the Sun. Analyse whether evidence from the graphs supports this argument.

Explain how increased levels of atmospheric carbon dioxide contribute to global warming.

Suggest reasons for the differences in LAI between the boreal and equatorial zones.

Analyse the data shown in the graph for evidence of a relationship between LAI and El Niño events.

State the trend.

Global ecosystem modelling suggests that most of the change in LAI is due to increases in atmospheric carbon dioxide. Explain how rising atmospheric carbon dioxide (CO₂) concentration could cause the observed change in LAI.

State the effect of elevated CO₂ on net primary production in these young, developing forests.

Outline one benefit of conducting similar FACE experiments in multiple locations.

Evaluate the evidence from the bar chart that increases in carbon dioxide cause increases in carbon storage in young, developing forests.

Suggest reasons for the differences in LAI between the boreal and equatorial zones.

Analyse the data shown in the graph for evidence of a relationship between LAI and El Niño events.

State the trend.

Global ecosystem modelling suggests that most of the change in LAI is due to increases in atmospheric carbon dioxide. Explain how rising atmospheric carbon dioxide (CO₂) concentration could cause the observed change in LAI.

State the trend.

Global ecosystem modelling suggests that most of the change in LAI is due to increases in atmospheric carbon dioxide. Explain how rising atmospheric carbon dioxide (CO₂) concentration could cause the observed change in LAI.

State the effect of elevated CO₂ on net primary production in these young, developing forests.

Outline one benefit of conducting similar FACE experiments in multiple locations.

Evaluate the evidence from the bar chart that increases in carbon dioxide cause increases in carbon storage in young, developing forests.

Describe how human activities have caused average surface air temperatures on Earth to increase.

Describe how human activities have caused average surface air temperatures on Earth to increase.