Meiosis Flashcards
Meiosis
it is the process of cell division to produce gametes
Location
int the sexual glands
Importance
for conservation of species
phases of meioses
meioses 1 and meiosis 2
what is meiosis 1 called? why?
it is called reductional division since the number of chromosomes is reduced into half
what is meiosis 2 called? why?
it is called equational division since the number of the chromosomes remains the same
number of chromatids in the beg and end of meiosis 1 1
beg: 2 chromatids
end: 2 chromatids each
number of chromatids in the beg and in the end of meiosis 2
beg: 2 chromatids
end: 1 chromatid each
prophase 1
- centromere duplicates and changes into 2 asters
- chromatin condenses to become chromosome
- the 2 homologous chromosomes are pairing up or synapsing to form tetrads where crossing over takes place for exchange of genetic material
- nuclear membrane disappears
Metaphase 1
- asters occupy different poles and achromatic spindle fibers extend between both poles
- tetrads (homo. chromosomes) line up at the equator forming an equatorial plate
Anaphase 1
- the homologous chromosomes separate and migrate to different poles
- each chromosome contains half of the number of chrs of the mother cell
- there is polar ascension
Telophase 1
- a constriction in the middle of the cytoplasm divides the cell into 2 daughter cells
- each daughter cell contain half the number of chrs of the mother cell and each chromosome is made up of 2 chromatids
Prophase 2
- nuclear membrane is disappearing
- chromosomes of 2 chromatids each is visible
Metaphase 2
- chromosomes of 2 chromatids line up at the equator forming an equatorial plate
Anaphase 2
chromosomes of 2 chromatids separate and migrate to different poles( polar ascension)
