Sexual Reproduction in Plants (Cambridge O Level Biology)

Exam Questions

1 hour15 questions
1a
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5 marks

The boxes on the left contain the names of flower parts.

The boxes on the right contain descriptions of the functions of the flower parts.

Draw one straight line from each box on the left to one box on the right to link the flower part to its function.

Draw five lines.

097031-may-2019-paper-3-q1a-flower-parts---sq

1b
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2 marks

Pollen grains from wind-pollinated flowers and insect-pollinated flowers are different.

State two ways in which a pollen grain from a wind-pollinated flower is different to a pollen grain from an insect-pollinated flower.

1c
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6 marks

Complete the sentences about seeds.

Use words from the list.

Each word may be used once, more than once, or not at all.

asexual  carbon dioxide gravity  hormones
light  mineral ions oxygen  sexual
vitamins  water    

 

Plants produce seeds as a result of .............................................. reproduction. Seeds germinate if they have the correct conditions. These conditions include a suitable temperature and also .............................................. and .............................................. .

The germinating seed produces a young root which grows downwards in response to .............................................. . The young root absorbs .............................................. and .............................................. from the soil as well as keeping the young plant in a stable position.

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1a
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2 marks

Define the term pollination.

1b
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2 marks

Fig. 1 shows a flower that reproduces using wind-pollination.

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Fig. 1

Describe two ways in which the flower in Fig. 1 is adapted for wind-pollination.

1c
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3 marks

Fig. 2 shows two photomicrographs of pollen.

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Fig. 2

Describe, using your knowledge and the information in Fig. 2, how pollen from an insect-pollinated flower is different to pollen from a wind-pollinated flower.

1d
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3 marks

Sexual reproduction in plants results in seeds being formed.

State three conditions needed for the germination of seeds.

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2a
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8 marks

Fig. 1 shows a section through a flower.

cie-igcse-2020-specimen-p3-q7a-flowerFig. 1

(i)

Write one letter from Fig. 1 to identify each of the following.

You may use each letter once, more than once, or not at all.

 Petal  
 Anther  
 Stigma  
 A male part of the flower  
 A part of the carpel  
 Sepal  

[6]

(ii)
Describe the evidence that this flower is pollinated by insects.
[2]
2b
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2 marks

Fig. 2 shows pollen grains from the flowers of several different species, labelled with the letters KQ.

cie-igcse-2020-specimen-p3-q7b-pollen

Fig. 2

State the letters of the pollen grains that come from insect-pollinated flowers.

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3a
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4 marks

Fig. 1 shows sections of two flowers, K and L, from the same species.

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Fig. 1

(i)
On flower L in Fig. 1, identify and label an ovule and a petal.

[2]

(ii)

State the names of the parts in Fig. 1 that: 

  • produce ovules
  • protect the bud of the flower
[2]
3b
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2 marks

On Fig. 1, draw an arrow to represent the transfer of pollen from flower K to flower L during pollination.

3c
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2 marks

A student said, “Flowers K and L are pollinated by insects.”

Describe two structures in flowers K and L that support this statement. 

Use features that are visible in Fig. 1. 

3d
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4 marks

Describe the pathway water takes in a plant, as it moves from the soil to a leaf.

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4a
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4 marks

Fig. 1 is a half-flower drawing of pride of Barbados, Caesalpinia pulcherrima.

cie-igcse-2018-s3-p4-q6a

Fig. 1

Complete Table 1 by stating the letter from Fig. 1 that indicates the organ where each function occurs and the name of the organ.

Table 1

function letter from Fig. 1 name of the organ
meiosis to produce pollen grains    
pollination    
development of seeds    
protection of flower in the bud    

4b
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4 marks

Extended Only

Fig. 2 is a scanning electron micrograph of some pollen grains from wind-pollinated flowers and insect-pollinated flowers.

cie-igcse-2018-s3-p4-q6b

Fig. 2

(i)

Write the formula that would be used to calculate the actual diameter of pollen grain H.

[1]

(ii)

The actual diameter of pollen grain H is 0.082mm.

Convert this value to micrometres (μm).

[1]
(iii)

Explain how the pollen grain labelled J is adapted for insect pollination.

[2]
4c
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3 marks

Extended Only

Pollen grains grow tubes, which contain haploid male gamete nuclei.

(i)

One of these male gamete nuclei fuses with the female gamete. State the part of the flower that contains the female gamete

[1]

(ii)

Define the term haploid nucleus.

[1]
(iii)

Explain why it is important for gametes to be haploid.

[1]

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1a
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2 marks

Explain the difference between self-pollination and cross-pollination.

1b
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4 marks

Some plant species are self-pollinated.

Discuss the long-term effects of self-pollination on the evolution of these plant species.

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2a
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4 marks

Some students investigated the conditions needed for the germination of maize seeds. They used maize seeds from a packet of seeds they had purchased in a shop.

Three dishes were used, each containing cotton wool and the same number of maize seeds, as shown in Fig. 1.

061032-oct-2018-paper-3-q2a-maize-seeds---sq

Fig. 1

Table 1 shows the conditions provided for each dish. 

Table 1

conditions dish
A B C
treatment of cotton wool damp dry damp
temperature / °C 20 20 3
light or dark light light dark

The seeds were left for five days and then observed.

The results are shown in Table 2

Table 2

dish results
A all seeds germinated
B no seeds germinated
C no seeds germinated

(i)
Explain why the seeds in dishes B and C did not germinate.

[2]

(ii)

In a second investigation, maize seeds were placed in a dish containing damp cotton wool.

This dish was left in the dark for five days at 20°C.

Predict and explain the results.

[2]

2b
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3 marks

A student gathered 70 maize seeds from plants growing in a field. The seeds were placed in dishes containing damp cotton wool.

After five days, only 64 seeds had germinated. 

(i)

Calculate the percentage of seeds that germinated.

Show your working.

Give your answer to the nearest whole number. 

[2]

(ii)

Suggest a reason why some of the seeds did not germinate.

[1]

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3a8 marks

Fig.1 shows a photomicrograph of a pollen grain with a pollen tube growing from it.q3a-16-3-sexual-reproduction-in-plants-hard-sq-cie-o-level-biology

Fig. 1

A student placed pollen grains from the same type of plant in sucrose solutions of different concentrations for a fixed amount of time. After this time, the student used a microscope to examine the grains and tubes.

Table 1 shows the results of the investigation.

Table 1

% sucrose
concentration
% of pollen grains
germinated
mean pollen tube
length / mm
1 6 0.005
2 13 0.008
4 25 0.015
8 56 0.040
10 31 0.030
20 25 0.018
40 13 0.006

 

(i)
A total of 12 pollen grains were placed in the 20% sucrose solution.

Using the information in Table 1, calculate the number of pollen grains that germinated to produce a pollen tube in the 20% sucrose solution.

[1]

(ii)
Suggest why the mean pollen tube length was calculated for each sucrose concentration.

 [1]

(iii)
Using the information in Table 1, identify the optimum (best) concentration of sucrose solution for pollen grain germination and pollen tube growth.

 [1]

(iv)
Explain how you used the information in Table 1 to answer (iii).  

[2]

(v)
The germination of a pollen grain requires the movement of water into the pollen grain to form a pollen tube.

Suggest why placing a pollen grain in a solution with a higher sucrose concentration than in your answer to (a)(iii) may result in a lower percentage of germination.

[3] 

3b4 marks

Describe the route taken by a growing pollen tube in a plant and explain the importance of this route in plant reproduction.          

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