Syllabus Edition

First teaching 2014

Last exams 2024

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Meiosis (DP IB Biology: HL)

Exam Questions

3 hours35 questions
1a1 mark

The diagram below summarises the processes of mitosis and meiosis.

3-3

Identify the process marked X in the diagram.

1b1 mark

Identify the stage of the cell cycle during which the process marked X in part a) takes place.

1c2 marks

Describe one way in which the process marked X in part a) can increase genetic variation.

1d2 marks

Describe the chromosome activity taking place at the stage marked Y in the diagram in part a).

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2a3 marks

The diagram below shows two chromosomes during meiosis.

crossing-over-structure-sq

Identify structures X-Z.

2b3 marks

Outline the events shown in the diagram in part a).

2c3 marks

At the end of meiosis the chromosomes shown in part a) form four new chromosomes, as illustrated in the diagram below.

Annotate the four new chromosomes below to show the results of the events shown in part a). The first chromosome has been annotated for you.

chromosomes-after-crossing-over-sq

2d2 marks

Outline the importance of the process shown in part a) to living organisms.

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3a2 marks

The diagram below shows a cell in anaphase of meiosis I.

Meiosis anaphase I

State how it is possible to know the following:

(i)

That the cell is in anaphase.

[1]

(ii)

That the cell is in meiosis I.

[1]
3b1 mark

Meiosis I is described as reduction division.

State why this is the case.

3c2 marks

Meiosis I generates genetic variation due to the process of crossing over.

Outline one other process during meiosis I that generates genetic variation.

3d
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2 marks

Rice, Oryza sativa, has a chromosome number of 24.

Use the formula 2n to calculate the number of different chromosome combinations that can be generated when rice cells undergo meiosis I. Note that the term n here denotes the number of pairs of chromosomes.

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4a2 marks

The diagram below shows chromosomes from a garden pea plant, Pisum sativum, during meiosis.

mq5a

Identify, with a reason, the meiotic division that is occurring in the diagram.

4b1 mark

Mendel's law of independent assortment states that:

'Characteristics are inherited completely independently of each other'

While the chromosomes in part a) will undergo independent assortment during meiosis, this law of Mendel's cannot be correctly applied to the characteristics for which genes A and B code.

Explain why this is the case.

4c2 marks

At the end of meiosis, the chromosomes were distributed to the pea plant pollen grains as shown below.

mq5b

Explain how the chromosomes in part a) gave rise to the new allele combinations shown above.

4d1 mark

The process in part c) and independent assortment both contribute to genetic variation.

State one other process that contributes to genetic variation.

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5a3 marks

One mark is available for clarity of communication throughout this question. 

Draw an annotated diagram of chromosomal synapsis.

5b5 marks

Outline the events that take place during the second division of meiosis.

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1a2 marks

The following image shows a cell undergoing cell division.

q1a_10-1_meiosis_medium_ib_hl_biology_sq
 

Identify, with a reason, the type of cell division shown in the image.

1b2 marks

The image below illustrates the formation of sperm cells, also known as spermatozoa.q1b_10-1_meiosis_medium_ib_hl_biology_sq

State and explain the change in chromosome number taking place during division I. 

1c2 marks

A sperm-producing cell in the testes has 46 chromosomes in its nucleus.

Calculate the number of chromatids that would be in the nucleus of this cell after it has undergone meiosis I.

1d2 marks

Outline the first steps in the process of meiosis, known as prophase I.

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2a1 mark

The image below shows a pair of chromosomes during meiosis, taking place in a testis of Drosophila melanogaster (a fruit fly). The position of the alleles of some genes is indicated.q2a_10-1_meiosis_medium_ib_hl_biology_sq

State the name of the arrangement of chromosomes shown in the image above.

2b2 marks

The diagram below shows two of the gamete nuclei that formed at the end of the meiosis process shown in part a). Assume that the parent cell only contains 2 chromosomes.q2b_9-2_transport_in_the_phloem_of_plants_medium_ib_hl_biology_sq

Draw the chromosomes in each of the nuclei shown in the diagram to give their appearance at the end of meiosis.

2c2 marks

Outline the events that occur during anaphase I of meiosis.

2d2 marks

Explain how independent assortment contributes to genetic variation in gametes.

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3a2 marks

European rabbits (Oryctolagus cuniculus) have a diploid (2n) chromosome number of 44.

The number of possible chromosome combinations that are possible as the result of independent assortment can be calculated using the formula 2n, where n is the haploid chromosome number.

Calculate the number of different possible chromosome combinations in the gametes of rabbits.

3b2 marks

The graph below shows how the mass of DNA changes over time during two different types of cell division of a diploid organism.

q3b_10-1_meiosis_medium_ib_hl_biology_sq
Identify, with a reason, which of the division types represents meiosis.

3c2 marks

Describe the two processes represented by the letters X and Y in the graph in part b).

3d2 marks

The fruit fly (Drosophila melanogaster) has a diploid number (2n) of 8.

The image below shows some cells from different organisms undergoing cell division.

q3d_10-1_meiosis_medium_ib_hl_biology_sq

   

Identify, with a reason, the cell which would represent a fruit fly cell that has just completed meiosis I.

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4a2 marks

Explain what is meant by the phrase ‘non-Mendelian ratio’.

4b2 marks

Explain how the work of Thomas Hunt Morgan provided a possible explanation for non-Mendelian ratios.

4c2 marks

Hydra are small, freshwater invertebrates that can reproduce by forming buds on their cylinder-shaped bodies. These buds grow over time, developing tentacles like the adult hydra, and eventually detaching from the parent hydra’s body.

Suggest why meiosis would not occur in Hydra during the process described above.

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5a7 marks

One mark is available for clarity of communication throughout this question. 

Describe the process of crossing over in prophase I.

5b5 marks

Compare and contrast meiosis II and mitosis.

5c3 marks

Draw a diagram to show how chiasmata are formed.

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1a3 marks

The graph below shows changes in the mass of DNA over the course of a cell cycle.

meiosis-mass-of-dna-graph-sq

Explain the role of the process, represented by this graph, in living organisms.

1b3 marks

Annotate the graph in part a) to show the approximate points at which the following events are taking place:

(i)

G2

[1]

(ii)

Cytokinesis I

[1]

(iii)

Metaphase II

[1]

1c2 marks

Variation is introduced at the points labelled X and Y in the graph in part a).

Identify processes that could introduce variation at points X and Y.

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2a1 mark

The diagram below illustrates the life cycle of the pea aphid, Acyrthosiphon pisum. Note that the term autosome refers to any chromosome that is not a sex chromosome.

aphid-life-cycle-sq

Identify the biological sex of the individuals labelled P and Q.

2b4 marks

The diagram in part a) shows that aphids use a different type of reproduction in the spring and summer to the type used in the autumn.

(i)

Identify the type of reproduction used by aphids in the spring and summer, and in the autumn.

[1]

(ii)

Explain your answer to part i).

[2]

(iii)

Suggest the advantage to the aphids of switching their method of reproduction in the autumn.

[1]

2c2 marks

Most eukaryotic chromosomes are described as being monocentric. Aphids have unusual chromosomes known as holocentric chromosomes. A holocentric chromosome after DNA replication is shown in the diagram below.

chromosome-structure-aphid-holocentric-sq

Contrast holocentric chromosomes with normal monocentric chromosomes.

2d4 marks

While scientific understanding of aphid meiosis is still limited, the holocentric nature of their chromosomes means that aphids are thought to carry out a form of meiosis known as inverted meiosis. The possible behaviour of a homologous pair of aphid chromosomes during metaphase I is shown in the diagram below.

-iDx-gkr_inverted-meiosis-homologous-pairs-crossing-over-sq

Suggest, with reasons, two ways in which meiosis in aphids could be different to conventional meiosis.

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3a3 marks

The spider mite Eutetranychus africanus has very few chromosomes (2n = 4).

The diagram below shows a series of cells undergoing cell division.

q3d_10-1_meiosis_medium_ib_hl_biology_sq

Identify, with reasons, which of the cells in the diagram above belong to E. africanus.

3b
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3 marks

A sample of cells was taken from the reproductive organs of E. africanus and the mass of DNA in each cell was determined. Some of the cells’ DNA had a mass of 1.7 arbitrary units (a.u.) whilst other cells' DNA had a mass of 3.4 or 6.8 a.u..

Use your knowledge of the cell cycle to explain this observation.

3c3 marks

A species of false spider mite, Brevipalpus phoenicis, is the only animal to have so far been identified as having exclusively haploid cells throughout its life cycle. B. phoenicis populations are entirely female, producing eggs which hatch into more females.

The discovery of the haploid nature of B. phoenicis was a surprise to scientists, who believed that being diploid was essential due to the evolutionary advantage that it provides.

(i)

Identify the type of cell division by which B. pheonicis produces eggs.

[1]

(ii)

Suggest why scientists might think that diploidy provides an evolutionary advantage.

[1]

(iii)

B. phoenicis is a highly successful pest of citrus, tea, and palm plantations. Suggest how B. phoenicis might have evolved to become such a successful pest despite the points covered in parts i) and ii) above.

[1]

3d3 marks

While studying the cells of B. phoenicis scientists discovered that the cells of all individuals contained bacteria. Treatment with antibiotics caused female B. phoenicis to lay eggs that hatched into haploid males.

(i)

Suggest the experimental measure that the scientists would need to take in order to demonstrate that the link between antibiotic treatment and male egg development is causal.

[1]

(ii)
Suggest why treatment with antibiotics might have enabled the production of male offspring.

[2]

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4a3 marks

The diagram below shows three cells in different stages of cell division. Note that all of the cells shown have the same 2n chromosome number.

gene-loci-drosophila-mendelian-ratios-crossing-over-sq

Identify the cell(s) in the diagram above that show the following:

(i)

Homologous chromosomes

[1]

(ii)

Meiosis

[1]

(iii)

Reduction division

[1]

4b
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2 marks

Fruit flies, Drosophila melanogaster, are frequently used in scientific studies. The diagram below shows the gene loci and alleles of two genes on a pair of chromosomes in a male and female D. melanogaster individual. Note that the dominant alleles are long legs and red eyes.

314f7eef-f727-43d6-b876-d08e09ce2d77

A cross was carried out between the two individuals shown above. The table below shows the number of offspring with short/long legs and brown/red eyes produced from the cross.

Characteristics Number of offspring
Short legs and brown eyes 545
Long legs and red eyes 182
Short legs and red eyes 14
Long legs and brown eyes 12

Calculate the offspring ratios for the cross shown. Give your answers to the nearest whole number.

4c3 marks

Explain the offspring ratios shown in part b).

4d2 marks

The diagram below shows the gene loci and alleles for a third gene on the chromosomes of the individuals in part b). Note that the grey body allele is dominant to the black body allele.

7c6274ff-8092-4386-b9a9-054d31f59e1a

Suggest, with a reason, how the numbers of offspring with short/long legs and black/grey bodies would differ from the numbers with short/long legs and brown/red eyes shown in part b).

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5a8 marks

One mark is available for clarity of communication throughout this question. 

Compare and contrast meiosis I and meiosis II.

5b6 marks

Use named examples to describe the roles of mitosis and meiosis in living organisms.

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