CAIE IGCSE Biology 16.3 Sexual Reproduction in Plants Questions

Practise plant reproduction questions by labelling flower parts, comparing pollination adaptations and sequencing pollen-tube fertilisation.

Exam points

label flower structures and compare insect- and wind-pollinated adaptations using petals, nectar, anther/stigma position and pollen features
define pollination as anther-to-stigma transfer, distinguish it from fertilisation, and trace pollen-tube growth and nuclear fusion in the ovule
distinguish self- from cross-pollination and compare their effects on variation, adaptation and reliance on pollinators
interpret seed-germination investigations using water, oxygen and suitable temperature requirements

Covered syllabus points

16.3.1—Draw the following parts 16.3.2—Functions of the structures listed 16.3.3—Describe the anthers and stigmas 16.3.4—Pollen grains of insect-pollinated 16.3.5—Pollination as the transfer of pollen 16.3.9—Self-pollination as the transfer 16.3.10—Cross-pollination as the transfer 16.3.11—Potential effects of self-pollination 16.3.6—Fertilisation occurs when a pollen 16.3.7—Structural adaptations 16.3.8—Environmental conditions that affect 16.3.12—Growth of the pollen tube and its

[Maximum number: 7]

(a)

Fig. 6.1 is a half-flower drawing of pride of Barbados, Caesalpinia pulcherrima.

Fig. 6.1

Complete Table 6.1 by stating the letter from Fig. 6.1 that indicates the organ where each function occurs and the name of the organ.

Table 6.1

[ 4 ]

process / event	letter from Fig. 6.1	name of the organ
meiosis to produce pollen grains	C	anther
pollination	D	stigma
development of seeds	E	ovary
protection of flower in the bud	A	sepal

(b)

Fig. 6.2 is a scanning electron micrograph of some pollen grains from wind-pollinated flowers and insect-pollinated flowers.

Fig. 6.2

[ 2 ]

(i)

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

[ 2 ]

(c)

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

[ 1 ]

(i)

One of these male gamete nuclei fuses with the female gamete.

State the part of the flower that contains the female gamete.

[ 1 ]

[Maximum number: 1]

The diagram shows a flower.
In which structure do seeds develop?

Figure for Question 2 — CAIE IGCSE Biology

[Maximum number: 13]

(a)

Fig. 3.1 shows part of a classification diagram for plants.

[ 2 ]

(i)

Complete Fig. 3.1.

Fig. 3.1

[ 2 ]

(b)

Fig. 3.2 shows the life cycle of a fern. The life cycle of a fern has some similarities and some differences compared with the life cycles of other plants.

The letters represent processes that occur during the life cycle.
The haploid stages of the life cycle are represented by (n).
The diploid stages of the life cycle are represented by (2 n).

Fig. 3.2

[ 4 ]

(i)

Identify and describe process A in Fig. 3.2.

[ 3 ]

(ii)

State the name of process D in Fig. 3.2.

[ 1 ]

(c)

Fig. 3.3 shows the parts of two flowers from two different plants of the same species.

Fig. 3.3

[ 7 ]

(i)

Annotate Fig. 3.3 to show the mechanism of cross-pollination by:
- labelling the structures involved
- drawing an arrow to show the pathway of pollen.

[ 3 ]

(ii)

Draw an X on Fig. 3.3 to show where fertilisation occurs.

[ 1 ]

(iii)

Explain the disadvantages of cross-pollination compared with self-pollination.

[ 3 ]

[Maximum number: 2]

Fig. 6.2 is a scanning electron micrograph of some pollen grains from wind-pollinated flowers and insect-pollinated flowers.

Fig. 6.2

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

[Maximum number: 3]

Fig. 3.2

Identify and describe process A in Fig. 3.2.

[Maximum number: 1]

Which row describes self-pollination?

pollen transferred from an anther to the stigma of a different flower on the same plant

pollen transferred from an anther to the stigma of a flower on a different plant of the same species

pollen transferred from an anther to the stigma of the same flower

key ✓ = yes $\boldsymbol{x}=$ no

✓

$\boldsymbol{\chi}$

✓

[Maximum number: 2]

Fig. 2.1 is a photograph of a spider plant, Chlorophytum comosum. Spider plants can reproduce by producing an identical plantlet, which grows away from the single parent plant.

Fig. 2.1

The hazel tree uses cross-pollination rather than self-pollination.

Describe cross-pollination.

[Maximum number: 3]

Fig. 3.3 shows the parts of two flowers from two different plants of the same species.

Fig. 3.3

Explain the disadvantages of cross-pollination compared with self-pollination.

[Maximum number: 2]

Fig. 2.1 is a photograph of a spider plant, Chlorophytum comosum. Spider plants can reproduce by producing an identical plantlet, which grows away from the single parent plant.

Fig. 2.1

(a)

Fig. 2.2 shows pollen that has been released from the flowers of a hazel tree, Corylus avellana. These flowers are wind-pollinated.

Fig. 2.2

[ 2 ]

(i)

Explain why a hazel tree has to produce very large amounts of pollen.

[ 1 ]

(ii)

Describe how a stigma from a wind-pollinated plant is adapted for pollination.

[ 1 ]

[Maximum number: 3]

Acid rain has negative effects on many ecosystems.

(a)

Two groups of students were asked to investigate the effects of acid rain on the germination of pine tree seeds.

[ 2 ]

(i)

The students provided the environmental conditions that seeds need to germinate.

State two of these environmental conditions.

1
2

[ 2 ]

(b)

One group of students recorded the change in temperature as the seeds germinated in five insulated flasks, labelled A to E.

[ 1 ]

(i)

The students sterilised the seeds before their investigation.

Their teacher told them to use a sterilising solution to wash the seeds because steam would kill the seeds and prevent the seeds from germinating.

Explain why steam sterilisation would prevent seed germination.

The results from this group of students are shown in Table 5.1.

Table 5.1

[ 1 ]

[Maximum number: 4]

Fig. 2.1 is a photograph of a spider plant, Chlorophytum comosum. Spider plants can reproduce by producing an identical plantlet, which grows away from the single parent plant.

Fig. 2.1

Outline the events that occur in the flower after pollination.

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