BIOL 102 EXAM 2 Essay Question #4
What then happens to the ovule?
It becomes a seed which then becomes a fruit
What happens to the microspores?
They become pollen grains with a sperm nucleus
What do microsporocytes produce and how?
4 haploid microspores through meiosis
What do the microsporocytes of a flowering plant produce and how?
4 haploid microspores through meiosis
What happens to the 4 haploid megaspores?
3 degenerate by random and the 4th one goes through mitosis to produce two diploid egg nuclei.
What do megasporocytes produce and how?
4 haploid megaspores through meiosis
What does each megasporangia contain?
A diploid megasporocyte
What do microspores develop into?
A single haploid pollen grain with non-flagellated sperm & nucleus
What results from triple fusion?
A triploid endosperm for food storage
What is the result of a sperm fertilizing an egg?
Diploid zygote
What do the microsporangia of a flowering plant possess?
Hundreds of diploid microsprocytes
What happens to the sperm nucleus?
It goes through mitosis to produce two sperm nuclei
What happens to the seed of a conifer?
It is eventually released from the cone, lands, and germinates to become a pine seedling
What do anthers possess?
Microsporangia
What exist inside a staminate cone?
Numerous microsporangia cavities containing hundreds of diploid microsporocytes
What are the two sperm nuclei used for?
One for fertilization and the other is saved for triple fusion
What are the two egg nuclei used for?
One is used for fertilization and the other is used for food storage
What do ovulate cones possess?
Ovule cones that have numerous diploid megasporocytes
What happens to the seeds?
They are eaten by animals and are either left behind or excreted and germinate
How do pollen grains get sperm into the ovule?
They inject a tube into the style of a flower, where they find their way to an ovule
How do pollen grains get from a staminate cone to an ovulate cone?
Wind
What happens when an ovule becomes fertilized?
becomes a diploid zygote
What happens to the 4 haploid megaspores?
3 degenerate by random, and the 4th one goes through mitosis three times to produce 8 egg nuclei
What does the megasporocyte produce and how?
4 haploid megaspores through meiosis.
How does pollen get to an ovary for flowering plants?
It is transferred to the stigma of a flower by an animal
How does the sperm get to an egg?
The pollen grain inserts a tube at the base of an ovule, injecting its sperm & eventually fertilizing an egg
The ovule then becomes a
seed
What are the cones of a pine called?
Staminate and ovulate cones
What are the 8 egg nuclei used for?
Only one is used for fertilization, 2 are synergyds that help the sperm find the egg, 3 are antipodal cells with unknown functions, and the last two are polar nuclei saved for triple fusion later on.
What do ovaries of flowering plants possess?
Megasporangia