What is the dominant generation in the angiosperm life cycle?
Sporophyte (2n)
The visible plant is a diploid sporophyte.
What structures do flowers contain in the angiosperm life cycle?
Stamens (male) and Carpels (female)
Stamens produce pollen, and carpels contain ovules.
What process occurs in the anthers of stamens?
Meiosis to produce microspores (n)
Microspores develop into male gametophytes (pollen grains).
What is formed from the megaspores in the ovules?
Female gametophytes (embryo sacs)
Megaspores develop into embryo sacs after meiosis.
What is pollination?
The transfer of pollen to the stigma of a flower
This can occur via wind, insects, or other means.
What is double fertilization?
One sperm fertilizes the egg to form a zygote, another sperm fuses with polar nuclei to form endosperm
The zygote becomes the embryo, and the endosperm provides nourishment.
What does the ovule develop into after fertilization?
Seed
The ovule matures into a seed containing the embryo.
What does the ovary mature into in the angiosperm life cycle?
Fruit
The fruit protects the seed and aids in dispersal.
What happens during germination?
The seed germinates and the embryo grows into a new sporophyte
This restarts the angiosperm life cycle.
What is the ploidy level of the sporophyte stage?
2n
The sporophyte is diploid.
What is the composition of the megagametophyte?
7 cells and 8 nuclei
The megagametophyte is also known as the embryo sac.
What are the two types of flowers based on ovary position?
Hypogynous and Epigynous
Hypogynous has a superior ovary, while epigynous has an inferior ovary.
What is a dioecious plant?
A plant with unisexual flowers on separate plants
This contrasts with monoecious plants that have both types of flowers on the same plant.
What is the role of the integument in the ovule?
Forms the seed coat
Angiosperms have two integument layers, while gymnosperms have one.
Fill in the blank: The pollen grain is the _______ of angiosperms.
male gametophyte
The pollen grain is haploid and develops from microspores.
What unique feature do angiosperms have compared to gymnosperms?
Double fertilization
This results in the formation of both an embryo and triploid endosperm.
What is the significance of pollen grains in angiosperms?
They are the only haploid stage and important for genetic diversity
Pollen grains allow for gene dispersal.
What is an inflorescence?
A cluster of flowers
Inflorescences can vary in arrangement.
What is the function of the synergid cell in the megagametophyte?
Directing/ guiding cells for the pollen tube
They help ensure successful fertilization.
What is the role of the tapetum in the anther?
Nutritive layer that surrounds the developing sporocytes
It provides extra nutrition for pollen development.
True or False: Angiosperms have archegonia.
False
Unlike gymnosperms, angiosperms do not have archegonia.
