plant sex Flashcards
What is one possible theory explaining the origins of sexual reproduction that I presented in
class.
Mitochondria did it
used oxygen to create reactive oxygen species that can cause damage to DNA so sexual reproduction evolved to provide a backup set of genome (extra one) so that cells would not immediately die if their DNA was damaged.
Describe alternation of generations in angiosperms. Be sure to include: where the male and female gametophytes are located, where meiosis and mitosis takes place, what is the sporophyte, where does fertilization take place.
Angiosperms alternate between a distinct haploid and diploid stage. The gametophytes are haploid and go through mitosis to make gametes. These haploid gametes then fuse to form a diploid zygote and this is where fertilization takes place. The zygote grows into a sporophyte, which makes haploid spores through meiosis. These spores can be either macrospores (female) or micro spores (male). Finally, the spores grow into gametophytes through mitosis and can be anthers (which hold the male gametophyte) or ovules (which hold the female gametophyte), and then the cycle is repeated.
Identify the parts of an idealized flower
Have sepals, petals, stamens and carpels
Male parts = stamens = anther and filament
Female parts = carpel = stigma, style, pollen tube, ovary, and ovule
Inside the ovule, identify (label) the antipodal cells, polar nuclei, egg, synergids, and micropyle.
Describe each of their primary functions in a sentence.
antipodal cells help nourish the growing embryo of the plant, polar nuclei allow for double fertilization, and formation of endosperm, synergids stop pollen tube growth and help release sperm cells, and the egg holds genetic material for the new daughter plant, and the micropyle is where the pollen tube enters the ovule
Explain what is meant by double fertilization and explain why its important
one sperm fertilzes the egg, the second fertilizes the polar nuclei
Important because each ovule develops into a seed after double fertilization and the fertilization of the polar nuclei creates the endosperm
Which parts of the carpel develops into the seed and the fruit?
The ovule develops into a seed and the ovary develops into the fruit
Where does the endosperm come from?
The fertilization of the polar nuclei
Provide examples of how plants prevent self-fertilization
Physical distance between or different maturity times of their stamens and carpels and self-incompatibility in which they are able to recognize and reject their own pollen
zygote
Result of fertilization of egg cell by sperm cell (diploid)
microspore
Male spore that gives rise to male gametophyte
macrospore (megaspore)
Female spore in ovule that becomes female gametophyte
anther
Produce pollen and hole male gametophyte
carpel
Female parts of plant, include ovary, ovule, and stigma
stigma
Where pollen grains land
style
Tube that leads from stigma to ovary
