Summary
Sexual reproduction in plants involves the fusion of haploid nuclei to form a diploid zygote, resulting in genetically diverse offspring. The flower is the sexual organ of a plant, containing both male and female parts, and pollination is the transfer of pollen from the male part to the female part.
- Pollination — transfer of pollen grains from the anther to the stigma. Example: Insect-pollination and wind-pollination.
- Gamete — a sex cell with a haploid nucleus. Example: Pollen in plants.
- Zygote — a fertilized egg cell with a diploid nucleus. Example: Formed when pollen nucleus fuses with ovule.
- Insect-pollinated flower — flowers with features to attract insects. Example: Bright petals and nectar.
- Wind-pollinated flower — flowers adapted to disperse pollen by wind. Example: Long anthers and feathery stigmas.
- Self-pollination — pollen from a flower lands on its own stigma. Example: Reduces genetic variety.
- Cross-pollination — pollen from one plant lands on the stigma of another. Example: Increases genetic variation.
Exam Tips
Key Definitions to Remember
- Pollination: Transfer of pollen from anther to stigma.
- Gamete: A sex cell with a haploid nucleus.
- Zygote: A fertilized egg cell with a diploid nucleus.
Common Confusions
- Confusing self-pollination with cross-pollination.
- Mixing up insect-pollinated and wind-pollinated flower features.
Typical Exam Questions
- What is pollination? Transfer of pollen from the anther to the stigma.
- How do insect-pollinated flowers attract insects? With bright petals and nectar.
- What is the advantage of cross-pollination? It increases genetic variation.
What Examiners Usually Test
- Differences between self-pollination and cross-pollination.
- Features of insect-pollinated versus wind-pollinated flowers.