Plant reproduction

• Which parts of the flower make up the carpel(f)?

  -Stigma

  -Style

  -Ovary
• Which part of the flower make up the stamen(m)?

  -Anther

  -Filament
• Where abouts in the flower are the male gametes/pollen made?

  Pollen grains in the anthers
• Where abouts in the flower are the female gametes made?

  Ovules
• List 6 features of insect pollinated flowers

  -Colourful petals

  -Scent and nectar

  -Anthers within the flower

  -Stigma within the flower

  -Small quantities of sticky, sculptured pollen

  -Produces larger pollen grains
• List 6 features of wind pollinated flowers 


  -Petals are green, usually small or absent

  -No scent or nectar

  -Anthers hanging outside the flower

  -Large, feathery stigmas hang outside the flower

  -Large quantities of smooth pollen

  -Produces smaller pollen grains
• What is cross pollination?

  Transfer of pollen from the anther of one flower to the stigma of different flower of the same species.
• What is self-pollination?

  Self-pollination is the transfer of pollen from the anther to the stigma of the same flower or plant.
• What are the 3 advantages of cross pollination?

  -Greater variation

  -Reduces chance of harmful allele combinations

  -Greater evolutionary significance: more different combinations of alleles mean some members are more likely to survive than others
• How do plants reduce self pollination?

  Stamen and stigma ripen at different times of the year
• What are the names of the two nuclei in a mature pollen grain?

  -tube nucleas

  -generative nucleas
• Which type of cell division produces two sperm nuclei from the generative nucleus?

  Mitosis
• Describe pollen tube growth

  -The pollen tube nucleus controls the growth of the pollen tube

  -The pollen tube nucleus grows out of a pollen grain in the cell wall , called a pit, and down the style , digests it’s way down the style(using protease enzymes)

  -The pollen tube grows through the gaps in the integuments, micropyle, and passes into the embryo sac
• How are meiosis and mitosis involved in gamete production in the anther?

  -In pollen sacs of the anther, diploid mother cells undergo meiosis

  -Each forms a tetrad, containing 4 haploid cells which become 4 pollen grains

  -Inside the pollen grain the haploid nucleas undergoes mitosis to produce two nuclei, a generative nucleus and a tube nucleus

  -The generative nucleas produces two male nuclei by mitosis
• Which nuclei fuse at fertilisation?

  Polar nuclei fuses with a male gamete forming a triploid cell
• What is the function of the exine?

  To help pollen be transported from anther to stigma-pits in the surface enables gas exchange
• In double fertilisation what do the gametes fuse with?

  -One male gamete and enters the embryo sac and fuses with the female gamete to produce a diploid zygote

  -The second male gamete fuses with the two polar nuclei to form a triploid endosperm nucleus