lesson 6 Flashcards
(32 cards)
What are the four floral whorls in a complete flower?
Calyx, corolla, androecium, and gynoecium.
What is the function of the calyx?
Protects the flower bud.
What is the main function of the corolla
Attract pollinators.
What structures make up the androecium?
Stamens, each with a filament and anther.
What does the gynoecium consist of?
Carpels, each with an ovary, style, and stigma.
What is the significance of bilateral symmetry in flowers?
It is considered more advanced than radial symmetry and may enhance pollination efficiency.
What are the male and female gametophytes in angiosperms?
Male: pollen grain (microgametophyte);
Female: embryo sac (megagametophyte).
How is pollen formed?
Microspore mother cells in anther undergo meiosis → microspores → mitosis → pollen grains with tube cell + generative cell.
What does the generative cell in pollen do?
Divides to form two sperm cells.
What is the embryo sac made of?
7 cells and 8 nuclei: 1 egg, 2 synergids, 3 antipodal cells, and 1 central cell with 2 polar nuclei.
What is the significance of pollen wall structure?
Species-specific features aid in identification and are resistant to degradation.
What is pollination
Transfer of pollen to the stigma.
What is self-pollination?
Pollen comes from the same flower or plant.
Why is self-pollination sometimes advantageous?
Ensures reproduction when pollinators are scarce; offspring are genetically similar to parent.
What is cross-pollination and its benefit?
Pollen from a different plant promotes genetic variation.
What does monoecious mean?
Male and female flowers on the same plant.
What does dioecious mean?
Male and female flowers on separate plants.
What is dichogamy?
Stamens and carpels mature at different times in the same flower.
What is self-incompatibility?
Pollen tube growth is blocked if pollen is genetically related to the stigma.
What is mutualism in pollination?
Pollinators get food; plants achieve fertilization.
Which colors attract bees?
Yellow and blue.
Which pollinators prefer red, tubular flowers?
Hummingbirds.
What is double fertilization?
One sperm fertilizes egg → zygote; other sperm joins polar nuclei → triploid endosperm.
What does the suspensor do?
Links the embryo to the nutrient tissue in the seed.
