Summary of Key Points (Leaving Cert Biology): Flashcards
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No. of pollen sacs in anther
No. of pollen sacs in anther
Four
Microspore mother cell (2n) division produces
Microspore mother cell (2n) division produces
4 haploid pollen grains (tetrad)
Two nuclei formed when pollen grain divides by mitosis
Two nuclei formed when pollen grain divides by mitosis
Generative nucleus & tube nucleus
Megaspore mother cell (2n) meiosis produces how many cells?
Megaspore mother cell (2n) meiosis produces how many cells?
4 haploid cells
Fate of 4 haploid cells in ovule
Fate of 4 haploid cells in ovule
3 die (degenerate), 1 becomes embryo sac
Distribution of 8 nuclei in embryo sac
Distribution of 8 nuclei in embryo sac
5 degenerate, 2 polar nuclei, 1 egg cell
Pollination definition
Pollination definition
Transfer of pollen from anther to stigma (same species)
Fertilisation definition
Fertilisation definition
Union of male & female gametes to form diploid zygote
1st fusion in double fertilisation produces
1st fusion in double fertilisation produces
Sperm nucleus (n) + egg (n) = zygote (2n)
2nd fusion in double fertilisation produces
2nd fusion in double fertilisation produces
Sperm (n) + 2 polar nuclei (n) = endosperm (3n)
3 necessary conditions for germination
3 necessary conditions for germination
Water, oxygen, suitable temperature
Radicle growth direction & tropism type
Radicle growth direction & tropism type
Grows down (geotropism)
Dry mass change during germination
Dry mass change during germination
Falls (respiration), then increases (photosynthesis)