Sexual Reproduction in Plants Flashcards
What does hermaphrodite mean?
Both male and female reproductive organs
What are the carpels?
The female structures
What structures are in the carpel?
Stigma, style and ovary
What is the stigma?
The platform upon which pollen grains may land
What is the style?
Supports the stigma
What is the ovule?
Contains the female gametes
What is the stamen?
The male structures
What does the stamen consist of?
Anther and a filament
What does the anther do?
Produces the pollen grains that contain the male gametes
What does the filament do?
Supports the anther in a position that will eventually enable it to shed its pollen grains
What is the nucellus?
The central mass of tissue in the ovule
What is the megaspore mother cell?
Diploid cell in the middle of the nucellus
What are integuments?
Layers of cell surrounding the megaspore mother cell
What is the micropyle?
The hole between the integuments
What are megaspores?
Haploid cells produced by the meiosis of the megaspore mother cell
Explain the formation of the female gametes
Megaspore mother cell divides by meiosis to form 4 haploid megaspores. 3 disintegrate, 1 left to grow. divides by mitosis 3 times to form 8 haploid nuclei in a cell called an immature embryo sac. Cytoplasm divides and form 7 cells. 3-2-3 formation of antipodal, polar nuclei then synergid cells and ovum
How many lobes does an anther have?
Two or four
What haploid nuclei are formed from the mitosis of the microspores?
Tube nucleus and the generative nucleus
What is the pollen grain?
A microspore containing two nuclei
What is pollination?
Transfer of pollen from an anther to a stigma of a plant of the same species
What is self-pollination?
Pollen goes from anther to stigma of the same plant
What is cross-pollination?
Anther to stigma of different plants
How can plants be cross pollinated?
Animals, insects, wind etc
What is needed for a pollen grain to germinate?
Pollen grain has to have complementary cell surface protrusions as the stigma
Explain the formation of the male gametes
Microspore mother cell divides by meiosis to form four haploid microspores. Each of these divides by mitosis once to form two nuclei: generative and tube nucleus
