Syllabus Edition

First teaching 2014

Last exams 2024

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Meiosis (DP IB Biology: SL)

Exam Questions

3 hours35 questions
1a2 marks

Outline the purpose of meiosis in living organisms.

1b2 marks

The table below contains a series of statements about meiosis in human cells.

Statement True / False
2 daughter cells are produced False
Homologous pairs of chromosomes are separated  
Daughter cells have the full number of chromosomes  
Two cycles of division take place  
DNA replication occurs before the process begins  

Complete the table by indicating whether each statement is true or false. The first row has been completed for you.

1c2 marks

The diagram below shows a simplified life cycle of a fern plant.

1-6

Identify the types of cell division taking place at the positions marked A and B.

1d1 mark

Identify the process taking place at the position marked C in the diagram in part c).

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2a2 marks

The process of meiosis was discovered in the late 1800s.

(i)

State one challenge that would have been faced by the scientists studying cell division at this time.

(ii)

Describe an observation that would have led to the discovery of meiosis.

2b3 marks

The image below shows two chromosomes.

e-2c

(i)

Identify the structures labelled X and Y.

[2]

(ii)

Structures Y and Z are identical.

State why this is the case.

[1]

2c2 marks

The two chromosomes shown in part b) can be described as homologous chromosomes.

Define the term homologous chromosome.

2d1 mark

During meiosis the homologous chromosomes shown in part b) are separated.

Identify the stage of meiosis during which the homologous chromosomes are separated.

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3a1 mark

The image below shows a summary of the events during mitosis and meiosis.

3-1

Identify the process taking place at the stage marked X.

3b2 marks

The stage marked Y on the image in part a) shows a change in the amount of genetic material in the cells.

Describe the events that take place in order for this change to occur.

3c2 marks

During division 1 shown in the image in part a) a process known as crossing over takes place.

Outline the events that take place during crossing over.

3d1 mark

Crossing over generates genetic variation.

Other than crossing over, identify one other process that generates genetic variation during sexual reproduction.

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4a1 mark

The image below shows a pair of chromosomes during meiosis.

mq3b

(i)

Identify the process taking place in the image.

[1]

(ii)

Label the image with an X to show the location of the chiasmata.

[1]

4b2 marks

State the alleles that will be present on each of the grey shaded chromatids at the end of the process shown in part a).

4c2 marks

There are many different possible combinations of chromosomes that can be found in the daughter cells produced during meiosis.

Use the formula 2n to calculate the number of possible chromosome combinations that can be generated in domestic cat gametes. Note that the adult cells of domestic cats contain 38 chromosomes.

4d2 marks

Another source of variation during meiosis is a chromosome mutation that results from an event known as chromosome non-disjunction.

(i)

State the meaning of the term non-disjunction.

[1]

(ii)

Identify one factor that increases the risk of chromosome non-disjunction occurring during meiosis.

[1]

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5a3 marks

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

Draw an annotated diagram of a cell in telophase I. The chromosomes should be clearly defined in your diagram.

5b5 marks

Outline the production of a karyogram for the purpose of screening the chromosomes of a developing embryo.

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1a2 marks

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

biology-q1a-sq-ib-hl-3-2

1b1 mark

Pisum sativum (garden pea) has a diploid chromosome number of 14. 

Calculate how many different chromosomal combinations can result during meiosis, assuming no crossing over occurs.

1c2 marks

Discuss the significance of meiosis in the life cycle of Pisum sativum (garden pea).

1d2 marks

Chlamydosaurus kingii (Australian Frillneck lizard) is a diurnal (active during the day) lizard whose distribution extends across northern Australia and into Papua New Guinea. If the lizard is startled it opens its mouth and flexes the muscles in its frill (a large fold of skin surrounding its throat) causing it to be raised. Scientists believe that the frill is used to deter predators and to attract females. 

The graphs below show the variation in the frill length of 164 male lizards from two different sites 150 km apart.

biology-3-2-q1d-sq-ib-hl

Explain how meiosis may have caused the variation shown in these graphs.

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2a2 marks

Complete the table using ‘yes’ / ‘no’ or numbers to compare mitosis and meiosis.

Feature Meiosis Mitosis
Number of nuclear divisions    
Number of daughter cells produced    
Genetically different daughter cells are produced    
Crossing over occurs    
Homologous chromosomes pair up    
2b2 marks

Explain how the diagram below illustrates that the resulting daughter cells will be genetically different. Give evidence from the diagram to support your answer

biology-3-2-q2b-ib-hl-sq

2c2 marks

The diagram below shows a pair of chromosomes during meiosis in a cell in a Drosophila melanogaster (fruit fly) testis. The position of the alleles of some genes is indicated.

biology-3-2-q2c-sq-ib-hl

Explain whether the chromosomes are homologous or non-homologous.  

2d3 marks

At the end of meiosis, each of the chromosomes shown in the diagram from part (c) will be in a different haploid cell.

biology-q2d-3-2-sq-ib-hl

Label the diagram above to show the combinations of alleles that would be present on each chromosome inside the haploid daughter cells.

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3a1 mark

The diagram shows the chromosomes found in a parent cell and the daughter cells produced after meiosis

biology-3-2-q3a-sq-ib-hl

Identify the daughter cell(s) that contain a chromosome mutation by circling the cell(s).

3b2 marks

Explain how the spontaneous chromosome mutation shown in part (a) arose in the daughter cells during meiosis. 

3c1 mark

The risk of a non-disjunction mutation increases with age. The table shows how the Down syndrome risk increases with age.

Mothers Age (Years) Chance of conceiving a baby with Down syndrome
25-29 1 in 1250
30-34 1 in 1000
35-39 1 in 400
40-44 1 in 100
45+ 1 in 30

Calculate how much more likely it is that a child is conceived with Down Syndrome for a mother who is 41 compared to a mother who is 26.

3d3 marks

Describe how the process of amniocentesis can be used to obtain cells which can be used for chromosome analysis.

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4a1 mark

The diagram below shows the life cycle of Calvatia gigantea (giant puffball). In this life cycle, only the zygote and mature puffball are diploid. All the cells in all the other stages of the life cycle of the puffball are haploid, including the spores.

biology-q4a-ib-hl-sq-png

Identify which letter in the diagram shows where meiosis occurs in the life cycle of Calvatia gigantea

4b4 marks

The micrographs below show cells undergoing meiosis.

biology-q4b-3-2-ib-hl-sq

Identify, with a reason, the stages of meiosis shown in each micrograph.

4c2 marks

A Pisum sativum (garden pea) pollen cell is undergoing meiosis. During the initial phase of meiosis a pair of homologous chromosomes located in these cells can be represented by the chromosomes shown below. The two different letters represent two different genes.

biology-3-2-q4c-sq-ib-hl

At the end of meiosis the chromosomes were distributed to the four pollen grains as shown in the gametes below.

Figure 2biology-3-2-q4c2-sq-ib-hl-png

Describe how the new allele combinations seen in these gametes were formed during meiosis. 

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5a4 marks

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

Draw a labelled diagram to show a cell in the following stages of meiosis:

  • Metaphase I
  • Prophase I
5b4 marks

Outline how developments in scientific methods facilitated the discovery of meiosis.

5c7 marks

Explain how genetic variation may be introduced into a population.

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1a4 marks

Rotifers are multicellular, aquatic animals that range in size from 50 μm to 3 mm. Their reproduction can be either asexual, resulting in the production of genetically identical females, or sexual, resulting in the production of eggs that can remain dormant for many years. A representation of a rotifer life cycle is shown in the diagram below.ph4-WAAe_h-1a

Annotate the diagram as follows:

(i)
Use the letter A to indicate one location within the asexual phase where mitosis is occurring.

[1]

(ii)

Use the letter B to indicate one location within the sexual phase where mitosis is occurring.

[1]

(iii)
Use the letter C to indicate two locations where meiosis is occurring.

[1]

(iv)

Use the letter D to indicate one location where fertilisation is occurring.

[1]

1b2 marks

Explain why meiosis is essential for sexual reproduction.

1c3 marks

Rotifers mainly reproduce asexually, switching to sexual reproduction for brief periods. The X in the diagram in part a) indicates the occurrence of a stimulus that shifts the rotifers from asexual to sexual reproduction. This stimulus could be a change in the environmental conditions, such as a drought that reduces the size of their habitat.

Use the information provided here and in part a) to explain why it is advantageous to rotifers to switch to sexual reproduction when environmental conditions change.

1d1 mark

Rotifers can be observed using an optical microscope.

Explain why this is the case.

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2a2 marks

Polyploidy is a condition in which cells have a chromosome number that is greater than the normal diploid (2n) number. Polyploidy is considered to be a useful characteristic in crop plants as it gives rise to bigger plant organs and provides cells which contain a larger variety of alleles for breeding programmes. While polyploidy can occur naturally in plants, it can also be induced artificially using a chemical called colchicine. Colchicine works by preventing the formation of the microtubules that make up the spindle fibres inside cells.

Suggest how colchicine gives rise to tetraploid (4n) cells after mitosis in plants.

2b3 marks

Plant scientists have been able to breed seedless watermelons by crossing tetraploid watermelons with regular, diploid plants to produce infertile, triploid (3n) plants. The diagram below illustrates this process. Note that diploid watermelons contain 22 chromosomes.

ZnD6VAIq_h-2b

Suggest why the offspring of the tetraploid-diploid cross are infertile.

2c3 marks

For the triploid offspring shown in part b) to start producing fruits, the triploid plants must be pollinated with pollen from diploid plants. Pollination involves the transfer of a plant gamete, pollen, from the flower of one plant to the flower of another. While the diploid pollen does not fertilise the triploid plants (they are infertile), it does trigger fruit production, and the resulting watermelon fruits are seedless. The graphic below shows a recommended planting plan for farmers that will ensure pollination of the triploid plants with pollen from diploid plants.

qD7~79a9_h-2c

(i)

State why diploid plants need to be used for pollination rather than other triploid plants.

[1]

(ii)

Suggest two disadvantages to farmers of the method described here and in part b) for growing seedless watermelons.

[2]

2d3 marks

A watermelon variety that naturally produces fewer seeds has been identified by scientists, and observation of its cells indicates that an event known as reciprocal translocation of chromosomes occurs in the cells of the watermelon variety. Reciprocal translocation of chromosomes involves the exchange of entire sections of chromosomes between non-homologous chromosomes during meiosis.

(i)

Contrast reciprocal translocation of chromosomes and crossing over with each other.

[1]

(ii)

Suggest how reciprocal translocation of chromosomes could result in a watermelon plant that produces fruits containing fewer seeds.

[2]

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3a2 marks

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

PIC42T3s_7

State what is happening at the following stages in the graph:

(i)

Stage X

[1]

(ii)
Stage Y

[1]

3b2 marks

Use the information provided in the graph in part a) to state, with a reason, which of the division types represents meiosis.

3c2 marks

The image below shows a diploid cell containing several chromosomes.

c3QwJ8r3_8

Draw the possible appearance of four different gametes that could be produced from this diploid cell during meiosis.

3d
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3 marks

A diploid cell contains 26 chromosomes.

(i)

Calculate the number of different combinations of chromosomes that could be generated when this cell divides by meiosis.

[1]

(ii)

Explain why the number calculated in part i) is not a true representation of the amount of genetic variation that can be generated from this cell during sexual reproduction.

[2]

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4a3 marks

Edwards syndrome is a rare but serious condition that influences birth weight and development. Death rates during infancy are high. The image below shows the karyogram of an individual with Edwards syndrome.

2-3

(i)

Use the karyogram to suggest the cause of Edwards syndrome.

[1]

(ii)

Describe the events that have led to the feature noted in part i).

[2]

4b2 marks

Edwards syndrome affects every cell in the body.

Explain why this is the case.

4c3 marks

One of the life-threatening complications that babies with Edwards syndrome can be born with is a structural abnormality in the heart. The image below shows a heart abnormality that can be seen in babies born with Edwards syndrome.

ELI7wUyq_3-2

Explain why the abnormality shown in the image can be life-threatening.

4d3 marks

The graph below shows the number of pregnancies affected by Edwards syndrome between 1985 and 2008.

Age and non disjunction graph Edwards syndrome

(i)

In the year marked X there were 1 100 000 pregnancies, and in the year marked Y there were 700 000 pregnancies.

Calculate the number of affected pregnancies at the times marked X and Y.

[2]

(ii)

Suggest one reason for the difference in affected pregnancies between times X and Y.

[1]

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5a8 marks

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

Describe the process of meiosis.

5b5 marks

Explain the link between meiosis and evolution.

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